research

There are two days left and Rae-Anne needs your support for her documentary film, Stable Island, The Beauty of the Free!

So far she has 102 backers who pledged $13,318; so close to her goal of $15,000!!! Just a small donation and she’ll be off to film a great documentary about our amazing wild horses on Sable Island.

If you haven’t already, check out Rae-Anne’s Kickstart for her documentary, Stable Island:

“The connections I have developed from my project are amazing. I feel so grateful to receive the support I have so far. It is truly beautiful to have others share my dream. I always wanted to work in a field where I could create positive change. Sable Island has a beauty too fragile for all to explore and a history too extraordinary to be hidden.” – Rae-Anne, Horse Journals

Visit StableIsland.com and share the dream!

Caspian horses are cute little riding horses that are becoming popular mounts for children. Even though they are small (9-12hh) they are referred to as horses as they are more similar in phenotype (how they look) to horses than ponies. They are reported to be a versatile, hardy and intelligent horse that is biddable and willing to work with people.

The breed originated when Louise Firouz sought out ponies for children to ride. She selected the small horses as foundation animals from various herds and locations around Northern Iran with the physical attributes she was looking for. Eventually she started a breeding program and called these horses Caspians because of their original locations near the Caspian Sea.

Because of the phenotype of the Caspian they were thought to be descendents of the original small horses in the area who are depicted on historical artifacts and drawings from the time of King Darius, the Persian ruler from 586 to 522 BC. Many believe Caspians to be ancestral to other breeds of horses. It is nice to believe that this new breed is actually directly descended from the foundation stock of the Persian Empire and have managed to remain relatively unaltered genetically.

So why are the Caspian horses different and how did they retain their genetic identity for over two thousand years while they mixed freely throughout various herds in Iran? The answer may be that they are not a breed at all, but rather a group defined by a genetic abnormality creating small horses from regular sized horses. This idea is supported by the work of Dr. Ardeshir Nejati of the University of Tehran,a genomic researcher looking at various native Iranian breeds.

Horse breeds can generally be classified as a set of individuals with distinct qualities and who produce similar offspring having the same distinct qualities. Inbreeding is consistently defined as an inbreeding coefficient (IBC) of 0.0333 (3.33%) or higher (a 3-3 match). The acceptable cutoff for inbreeding tends to be 0.0667 (6.67%). Linebreeding would be an IBC between 0.018 (1.8%) and 0.0333 (3.33%). Less than 0.018 (1.8%) is considered outbreeding, or a Hybrid.

In the paper, “Molecular Marker Genotypes and Measuring their Relationship with Caspian Horses”, they found that extreme heterozygosity existed between the Caspian horses tested, with an inbreeding coefficient of -0.0634 (-6.34%). These numbers indicate that Caspian horses can in fact be considered hybrids, meaning they have a great genetic variance. So even though they look similar (phenotype) they are actually genetically diverse, which makes sense as they were originally collected because of a similar phenotype but from distinct herds throughout the region.

Further research may indicate that the phenotypic similarities actually come from a set of genes that cause miniaturization. This is distinct from dwarfism and may be unique to this group of horses. It has been speculated that cross breeding throughout the region could have spread the genetics between the groups.

The good news is that the hybridization is beneficial for a population, usually accompanied with both health and performance benefits. Also of interest is that it should be possible to segregate the genes and create small versions of any horse breed. But despite their genetic background, the Caspian horse is becoming more popular as a child’s mount, which is the original purpose tfor which Louise Firouz sought them out.





Research is continuing and I will update this information as I get it! Kerri-Jo Stewart, MSc

Something to chew on

Forage is a staple in any horse’s diet, and the best sources are natural grasses and hay. But if your horse has special needs, here are 8 alternatives for consideration.

by Kerri-Jo Stewart, BPE, MSc
as published in Equine Wellness, Vol 7, issue 1; Jan/Feb 2012

Horses rely on a fairly continuous source of forage as their sustenance. In fact, at least 50% of their diet needs to consist of forage. Natural grasses and legumes can fill all the nutritional requirements for horses, and the fiber is needed to maintain a healthy digestive system. Hay is the common alternative when natural forage is unavailable. Unfortunately, good quality hay is not always easy to find, which means forage substitutes may be required.

The most difficult challenge with a forage substitute is to ensure adequate fiber and roughage. It appears there’s a relationship between behavioral issues and the time a horse spends chewing. Usually, the first problem to develop is wood chewing; tail chewing is also not uncommon. It’s believed that a certain amount of saliva production is necessary to act as a buffer in the hindgut. Reduced saliva production from decreased chewing time means digestive tract functionality is compromised.
Here are eight possible alternatives to feeding hay, along with their pros and cons.

1. Hay cubes

Hay is forage that is cut, sun cured and baled. For hay cubes, the forage can be either sun cured or dehydrated. Typically using timothy, alfalfa, or a combination of both, the forage is cut at an early stage of maturity and only partially dried in the field before being shipped to the processing plant and dehydrated. Then, instead of baling, it is coarsely chopped, mixed with a binder, compressed and set into a form. Different manufacturers use different supplements and binders which are listed on the label. Types and amounts of protein, minerals, molasses and oils all vary between brands, as does the caloric content. Check for the mixture that best matches your feeding needs.
There are some noted advantages to feeding the cubes over hay1. The processed cubes have lower moisture content, less mold and spores, and stay better longer, retaining their nutritional profile. They are easier to store and can generate less waste than hay. The nutritional profile is more uniform and the values are displayed on each bag. They can also be easier for older horses to chew, and may be more digestible. Soaking the cubes for easier chewing or for highly sensitive animals is also simpler than soaking hay, and may result in less dust and mold. For horses on special regulated feeding programs, it’s easier to monitor how much has been consumed with pellets or cubes than it is with hay.

On the downside, cubes are more expensive than hay because of processing costs, and horses finish them faster so spend less time chewing. It’s suggested that an appropriate type of hay is fed along with the cubes to prolong the feeding (a half to one pound daily). Also, you can’t see the purity of the feed because everything is ground together and looks the same. While some horses don’t like the texture of cubes, others may wolf them down, which means those predisposed to choke or digestive problems should have their food soaked. Because cubes are in a compact form, you need to guard against overconsumption.

In several research studies at Rutgers, Ralston reports good results from using hay cubes as the sole source of fiber2. Although they found an increased incidence of wood chewing in every study, Russell and Johnson3 reported that cubes made from coarsely chopped hay appeared to eliminate wood chewing.

Care needs to be taken when switching over from hay to a cubed feed. As with any change of feeding regime, it needs to be done slowly over time. In general, the cubed feed can be fed in the same amounts as hay, based on weight. Start by gradually adding the new feed in, and eventually feed up to 75% to 80% cubes over hay by weight5.

2. Hay pellets

Pellets go through the same manufacturing process as cubes, but they also go through a more intense grinding process. Again, different manufacturers use different mixes, binders and supplements as detailed on the labels. However, because of the smaller particle size of pellets, they have not been found to maintain a healthy digestive system. Pellets have also been linked to behavioral issues such as wood chewing and tail biting2 as well as increased searching and non-restful behavior6. A minimal recommendation is to feed 1% of the horse’s body weight per day with hay; however, that may not be sufficient. Pellets are not recommended as a complete forage substitute6.

3. Haylage

When creating haylage, forages are harvested at moisture levels between 45% to 70%, then stored in a container such as a plastic bag. The exclusion of air and the resulting low pH is required for preserving high-moisture forage. However, the risk of spoilage and toxic development during fermentation is very high for horses. Horses that are going to be fed haylage should be vaccinated against botulism2. Many people have used haylage to feed their horses, but how many fatalities there have been isn’t known. Research is also lacking about the effects of feeding a highly acidic feed to horses.

When haylage is exposed to air for feeding, it needs to be quickly consumed and should be monitored to ensure there is no mold or spore development3. Moving bales must be done carefully, as any tears or holes in the bag will cause a secondary fermentation and spoilage. Haylage should be used very cautiously if it is needed as a forage replacement. Also, because of the high moisture content, more haylage needs to be fed on a per weight basis than compared to hay.

4. Beet pulp

Beet pulp is a very digestible source of fiber. Because of the high fiber content it is considered a long-stemmed forage substitute. It is a popular supplement because of its low sugar content, high calcium and moderate protein levels (8%). In general, one pound of beet pulp is fed for every one-and-a-half pounds of hay that it replaces.

When used as a hay substitute, beet pulp shouldn’t make up more than 40% of the total forage. That’s because it doesn’t provide the long-stemmed forage component required for gut health. The traditional form has to be soaked, but the new pelleted form doesn’t. Up to ten pounds (dry weight) of beet pulp can be fed to an average mature horse, but he will also need a balanced vitamin/mineral supplement since beet pulp doesn’t contain vitamins. Some horses will also require additional protein.

5. Bran

Although wheat bran is often fed as a fiber supplement, it is not beneficial to horses, especially in large quantities over long periods of time. Bran has an inverted calcium to phosphorous ratio that can cause imbalances, as well as debilitating problems from the high phosphorous content. Rice bran has also been promoted as a source of fiber and energy (fat) for horses. However, rice bran has an even higher concentration of phosphorous than wheat bran. Neither rice nor wheat bran are recommended as a forage substitute2.

6. Chaff

Chopped hay and straw is known as chaff. Chaff can provide indigestible fiber essential in maintaining digestive tract health. It may also be used as something the horse can chew for an extended period of time. The quality of chaff can often be a concern, so it is important to check that it’s not contaminated with any molds or other substances that could be toxic to horses.

7. Complete feeds

Concentrates are sold as “complete feed” and some are labeled as a complete forage substitute. They can contain a mixture of hays, grains, beet pulp, and vitamin and mineral supplements, and are developed around various standard nutritional profiles (i.e., growth, maintenance, performance, broodmare). However, complete feeds don’t have the required fiber to maintain a horse’s health. It’s better to use them as a supplement to forage, not as a complete replacement.

8. Straw

Straw is the stalks remaining after harvesting a grain crop. It contains very little nutritional value but can be a good source of fiber. Straw may satiate a horse’s desire to chew when he is restricted from adequate sources of long-stemmed forage or sufficient fiber. Straw is not a source of nutrition.

Summary

The only true forage substitute for hay is hay cubes. The best hay cubes for supplementation are the ones with long-stem fiber of at least an inch in length. Pelleted feed, beet pulp and complete feed can be great nutritional products but don’t replace the long-stemmed fiber required for intestinal health. Straw can be added as a fiber source if no hay is available.

The increased consumption of dense, higher energy forage substitutes over hay can be a benefit or a drawback depending on the type of feeding requirements your horse has. Overweight horses on a restricted diet need sufficient nutrients. Processed feeds with nutrient details on the labels make it easier to manage and monitor nutrient intake.

At the other end of the scale, hard keepers are more likely to consume more feed overall with cubes or pellets (up to 25% more over hay3), and better maintain their weight. An animal unable to maintain a healthy body condition can be having dental or other problems to do with his ability to intake feed (pituitary problems, pain, or herd competition7), all of which should be looked into. Soaked hay cubes, beet pulp and/or complete feed can add needed nutrition in an easier to consume form.

References
1. Kentucky Equine Research, Inc, “Nutrition and Convenience in Cube Form”, Equinews, vol.9:2, www.ker.com/library/equinews/v9n2/v9n203.pdf.
2. Ralston, SL, Wright, B., Forage Substitutes For Horses, Government of Ontario, Ministry of Agriculture, Food and Rural Affairs, 2008, www.omafra.gov.on.ca/english/livestock/horses/facts/05-055.htm.
3. Russell, Mark A., Department of Animal Sciences and Johnson, Keith D., Department of Agronomy, Cooperative Extension Service, Purdue University, Selecting Quality Hay for Horses, http://www.agry.p­urdue.edu/ext/forages/publications/ID-190.htm
4. Coleman, RJ, Lawrence, LM, Henning, JC., Alfalfa Cubes for Horses, University of Kentucky, www.uky.edu/Ag/AnimalSciences/pubs/id145.pdf.
5. Johnson, Debra, “Feeding horses hay cubes”, http://horsehints.org/HayCubes.html.
6. Elia, JB, Erb HN, Houpt, K., “Motivation for hay: effects of a pelleted diet on behavior and physiology of horses”, Physiol Behav. 2010 Dec 2;101(5):623-7.
7. Jarvis, NG. Nutrition of the Aged Horse. Veterinary Clinics of North America: Equine Practice
Volume 25, Issue 1 , Pages 155-166, April 2009
8. Kentucky Equine Research Center: Kentucky Equine Research Staff · October 27, 2011

Slow down! A look at slow feeding and feeders.

by Kerri-Jo Stewart, BPE, MSc
as published in Equine Wellness, Vol 7, issue 3; May/Jun 2012

Although free feeding is considered best for horses, it is not always beneficial (or easy to do) in captive situations. Many people feed their horses three times a day, including hay, complete feed and/or grain. Although some horses eat slowly and others only eat what they need, many will eat their portions quickly and continuously until they are gone. Then they have to wait for the next feeding.

Forage, naturally

One problem is that we feed hay, which is concentrated grass, or have lush pastures, and our horses don’t have to move around much to obtain their food. In the wild, a horse may eat for 16 to 20 hours a day, grazing on sparse natural pasture, and travel an average of 12 miles in order to find adequate food. The purpose of slow feeders is to try to feed horses at a similar rate to wild foraging.

Slow feeding is called “restricted feeding” versus “free feeding”. Feed intake is limited by speed, not quantity. Horses can only take small bites, but the food is available at all times. In general, since the horse is meant to have a constant supply of small quantities of food travelling through the gut, the idea of slow feeding makes sense.

Touring the digestive tract

The equine stomach holds around four gallons. This is actually a small size for such a large animal and limits the amount of food a horse can eat at one time. There is a continuous production of acid in the stomach, and chewing creates saliva, which provides a protective coating. It is thought that without a continuous supply of saliva, stomach ulcers can become common.

The food then goes into the foregut or small intestine, which is 50’ to 70’ long and holds around 10 to 12 gallons of food and water. Almost all the protein digestion is done here, as well as around 50% to 70% of simple carbohydrate digestion. The nutrients are absorbed into the bloodstream. The primary mode of digestion here is enzymatic — enzymes break down proteins and carbohydrates, making them available for absorption. Food and water travel though the foregut in a matter of hours.

The hindgut of the horse is where digestion occurs, primarily through microbial fermentation. The first part of this system is the cecum, which is a sack about 4’ long and holds around seven to eight gallons. Then things move along to the large colon, which is around 10’ to 12’ long and holds up to 20 gallons. This is where fiber is broken down by fermentation into nutrients the horse can absorb. Impaction colic can occur here, especially when food isn’t constantly available.

The opposite problem of having too much food available at once also creates dramatic problems in the hindgut. Large grain meals cause a hindgut acidosis as the microbes increase the rate of fermentation. The increased acidity can damage the cellular walls and result in a leakage into the bloodstream.

The small colon is about 10’ to 12’ long and can contain around five gallons of now digested food and fluids. For the hindgut to work properly and remain intact (untwisted or un-kinked), the gut needs a constant supply of fiber and water. This will keep fermentation going consistently, effectively keeping the hindgut weighted and healthy and, as a result, preventing conditions that can contribute to colic.

Selecting or creating your slow feeder

There are numerous types of slow feeders being used and developed, and many people are creating their own as well. The basic idea is to make the horse work to get the food and thus not permit large mouthfuls of food. Small mesh nets are made so that horses can eat naturally close to the ground (preventing certain respiratory problems that can occur when horses eat with their heads elevated). The mesh needs to be small enough so the horses can’t get caught up on the nets. People use all kinds of netting, including hockey nets or commercially available purpose-made netting arrangements.

There are also hard grates as well as mobile hard feeders made specifically for dispensing either grain or hay. A hard mesh is placed over the hay, making the horse work at getting the feed so he is only able to eat small mouthfuls. There are even grain dispensers shaped like balls that only dispense food a couple of pellets at a time as the horse moves it around.

Ensure the feeder is safe, particularly if you create your own. Some people have reported their horses getting wounds on their noses from specific types of nets. Nets may also not be practical for shod horses. Others have noted that some types of metal gridding can cause damage to horses’ teeth. Also, ensure that any feeders are not able to splinter or break. Do your research before buying or constructing the right slow feeder for your horse’s needs, then monitor him with the feeder to ensure it is safe.

In the wild a horse may eat for 16 to 20 hours a day, grazing on sparse natural pasture, and travel an average of 12 miles in order to find adequate food.
Large grain meals cause a hindgut acidosis as the microbes increase the rate of fermentation. The increased acidity can damage the cellular walls and result in a leakage into the blood stream.

Here’s the nitty-gritty on soaking and steaming hay

by Kerri-Jo Stewart
as published in Jan/Feb 2011 Equine Wellness

Many of us have had to deal with soaking a horse’s hay, whether because of an airway sensitivity or allergy, or for nutritional reasons. And we can relate to the “joys” of handling soaked flakes in sub-zero temperatures (though with new equipment such as the Haydrator, this is getting easier). Now that there are more advanced ways of soaking and steaming hay, it means a greater investment on your part – so does it matter what method you use?

The air they breathe

Airborne particulates from hay can negatively affect a horse’s airways, causing respiratory disease and aggravating allergies. To improve air quality, the hay is soaked or steamed so that particulate can’t be released into the air while it is still wet. A Clements and Pirie study showed that although wetting the hay decreased airborne particles, there were many other airborne particulates that could negatively affect the respiratory status of stalled horses1. Air quality inside barns is directly related to ventilation and all the materials inside the barn, including bedding. Whatever was in the neighbouring stall was noted as being particularly important. So when searching for the reason your horse is coughing, make sure to look at all the surroundings.

Soak or steam?

Soaking hay has long been a popular way to reduce the quantity of dust particles released when horses eat. Now, steaming hay is being touted as a more efficient way to do the same thing. Some research has been done to look at the most beneficial length of time to soak hay in order to get the greatest particulate reduction, as well as the differences between soaking and steaming hay. Clements and Pirie found there wasn’t much difference between simply immersing hay in water and soaking it overnight1. A recent study by Kellon also found no differences between soaking times2. Their study also did not find any differences between steaming and soaking the hay.

Kellon’s trials soaked the hay for ten minutes and 30 minutes, and steamed it for 80 minutes. They found that airborne particulates were reduced by over 90% while the hay remained wet, regardless of the trial. They found that the amount of particulate reduction was the same across all methods of soaking and steaming.

Haygain, a steamer manufacturer, states that the primary reason for steaming hay is to control dust and mould spores that cause airway irritation3. They say steamers can eliminate bacteria like salmonella and the pathogens that cause botulism, thus preventing respiratory infections and allergies. Soaking does not completely remove these elements, but it does largely eliminate the possibility of spores being directly inhaled as small airborne particles.

Ensuring adequate ventilation, preferably by keeping your horse in an outdoor space, is key to reducing exposure to airborne particulates. If a horse has to be kept indoors, the barn must have excellent ventilation and nothing used inside the barn should produce airborne particulates. But in general, if decreasing airborne particulates is the goal, soaking hay is as effective as steaming.

WSC and the insulin resistant horse

The other major reason hay is soaked is to reduce the amount of water soluble carbohydrates (WSC), thereby decreasing the sugar content in the hay. Horses prone to laminitis resulting from insulin resistance and/or obesity should consume feed with less than 10% non-structural carbohydrate, composed of water soluble carbohydrate (WSC) and starch2,3. By soaking hay, the sugar content is leached out with the water and the hay is then believed to be safe for laminitis prone horses.

In an older study reported in The Horse, Watts found that soaking can reduce the WSC content by up to 56%4. However, the range in WSC reduction was huge, varying from none to 56%. The researchers analyzed various types of hay, including straight alfalfa, alfalfa-grass mixes, straight grass of several varieties and oat hay, and soaked them for various times in hot and cold water. They found a 10% increase in WCS reduction between soaking the hay for 30 minutes in cold water (average 20% reduction), and 60 minutes in cold and 30 minutes in hot water (average 30% reduction). They also found more correlation between the maturity of the hay than its type when it came to WSC decreases.

A 2009 study by the Laminitis Consortium analyzed nine different hay samples for WSC and soaked them for 20 minutes, 40 minutes, three hours and 16 hours5. They found a high variability of WSC in the soaked samples. Although the longer soak did lose more WSCs, very few samples fell below 10% even in the 16-hour soak. The greatest and most consistent loss of WSC was with hay soaked at 16˚C for 16 hours, averaging a loss of just less than 50%. The study’s conclusions were that soaking is an unreliable method for ensuring hay is safe for horses requiring a WSC content of less than 10%.

Watts and Ralston found that the average sugar percentage for grass hay ranges from about 6% to 15% but can range anywhere between 3% to 40%3. Given the huge variability in WSC decreases with soaking, it is highly advisable to know both the original quantity of WSC, and the quantity after soaking. A core sample should be taken for analysis following the soaking. This is the only way to know the percentage of WSC in the hay.

Kellon’s study showed no decrease in WSC content with steaming. To efficiently extract water soluble sugars, large volumes of water are required. Steaming hay is therefore not beneficial for laminitic prone horses.

Nutrient loss

Nutrient loss in any food during heating depends on the temperature, duration of heating, and the food type. In general, the longer a food is exposed to heat the greater its nutrient loss6. Current nutritional research typically covers steaming for up to ten minutes. Although testing for nutrient loss in steamed hay hasn’t been published, even 30 seconds in steam can alter the nutrient composition of a food and cause some nutrient loss. In general, however, short steaming times are not a practical problem. There is minimal nutrient loss, although temperature and type of food cause large variations in vitamin retention factors.

The Laminitis Consortium study also found that greater quantities of protein, vitamins and minerals were lost with longer periods of soaking. Other studies by Haygain have looked at nutrient loss and found that more than ten minutes of soaking leads to considerable mineral loss, particularly sodium, potassium and phosphorus7. Other potential losses include B vitamins, potassium and sodium6.

Palatability and digestibility

One touted benefit of steamed hay is that it is more palatable. Haygain states that horses are more likely to eat a poorer quality hay if it has been steamed. However, Kellon’s study found that horses did not prefer the steamed hay and required a few days to get used to eating it5. It is not known if steaming hay improves digestibility.

A benefit of soaked hay may be performance related. Water soaked feeds increase fluid intake, and soaked hay is easier to chew. Many endurance riders soak their hay during competition for the increased fluid intake.

In conclusion

Haygain consultants stated that 80% of horses who are stabled part of the time have some degree of airway inflammation that will affect performance3. Managing a stabled horse involves monitoring all materials in the barn to ensure a low level of airborne particulates, and ensuring the barn has adequate ventilation. Ideally the horse will spend the majority of his time outside.

Steaming hay may reduce mould and dust, but it is better to buy good hay without any mould. Horses should not be fed mouldy hay; be aware that adding water to hay may in fact cause mould to form in it. Likewise, if your hay requires steaming in order to kill organisms like salmonella and those that cause botulism, it is better not to use that hay for horse feed. However, of the two methods, steaming will be better at this than soaking, and will yield minimal changes to the hay’s nutrients and sugar components.

Since it is extremely important to feed laminitis prone horses a restricted sugar diet that’s less than 10% WSC, the content of WSC in the hay has to be known. Ideally, buy hay that has been tested and has the lowest WSC content. If the hay is over 10% WSC and is being soaked to lower the sugar content, then it needs to be sent for analysis after it’s dried to ensure that desired WSC levels are reached. This analysis also gives you the opportunity to balance your horse’s nutrient intake.

Kerri-Jo Stewart has a masters from the University of Guelph in equine physiology and nutrition. She lives with her family in Maple Ridge, BC, with various animals including Akhal-Tekes. She has just published her first photography book, Dreaming in Gold. You can find more about her at Argamak Equine Services.

1. JM Clements, RS Pirie, “Respirable dust concentrations in equine stables,” Res Vet Sci. 2007 Oct;83(2):263-8. Epub 2007 Apr 30
2. Kellon, EM, “Hay Steamers”, Horse-Journal.com, Vol. 17, Number 10, Oct 2010
3. Tietz, N, “Steam-Cooked Hay For Horses”, hayandforage.com, May 1, 2010
4. Walcott, K, “Feeding Horses With Laminitis”, thehorse.com, August 01 2004
5. Andrews, M, “Laminitis: value of soaking hay?” equinescienceupdate.co.uk , July 7, 2000
6. Wei Sheng, Yan Jiu, “Study on vitamin retention factors in vegetables”, Jan 2008; 37(1):92-6
7. Moore-Colyer 1996, Blackman & Moore-Colyer 1998, “Hay Steamers”
8. Haygain Hay Steamers

This is an experiment for me, I’m not recommending it to any one else. It seems that there is a broad spectrum of plants that have anti-nematodal / anthelmintic activities. The trick is in getting the correct amounts and most effective combination. I will do some fecals and start tracking it’s effectiveness and see what happens. I’m hopeful. It is less expensive than using the chemical dewormers (and I’m going to try to grow all my own ingredients!) and theoretically not as hard on an animal’s system.

I will give general recommendations about deworming no matter whatever you are using. I highly recommend getting fecal counts done (taking samples to your vet would be the easiest way!). Then you know exactly what you need to worm for!

Diatomaceous Earth has become a great friend and gets put everywhere any animals sleep (chicken coop, rabbit hutches, stalls) and high use areas such as entry ways. I only use it externally. I know that lots of people include it in their wormers for internal use but it doesn’t make sense to me to use it that way. It works by cutting the exoskeleton of insects and they dry out. Internal parasites don’t have chitinous exoskeletons as a general rule.

For the herbal preparation I have used equal parts of fennel seeds, dehydrated garlic, oregano, thyme, sage, hyssop, red clover and pumpkin seeds. I also add in Wormwood, although not on any pregnant animals. I added some mint as well as a thought at the time.

It is suggested to deworm in spring and summer by adding to feed rations (I put it in the beet pulp for horses and goats and in grain for the chickens) for the first week of every month:
Horses: 1/4 cup daily
Goats: 1 TBSP daily
Chickens: about 1 cup per 30 chickens daily

Wormwood
Various forms of {Artemisia absinthium} have been shown to reduce internal parasite loads in experiments with a variety of animals. The plant’s odor can also be useful in spraying against pests.

Pumpkin seeds
Pumpkin seeds are a good source of amino acids (including tryptophan), vitamins, and minerals (such as iron, magnesium, manganese, phosphorus, zinc) and phytosterols. The seeds have been shown in research to have anti-nematode properties and are noted by some for expelling tapeworms from the body.

Hyssop
{Hyssopus oficinalis} is a common perennial herb. The entire plant is traditionally used medicinally but most typically the flowering tops and leaves. Hyssop’s therapeutic actions are believed to be due to its essential oil, which is thought to have anthelmintic properties but I haven’t found any research to corroborate that.

Garlic
{Allium Sativum} has been used as an anthelmintic for centuries and is believed to have antibacterial, antimycotic and lipid-lowering effects. One paper  concluded that it doesn’t affect gastrointestinal nematodes in goats or sheep (1). However in another paper they showed that garlic was effective against an intestinal parasite in people, showing a great reduction in both the egg and worm burden (2).

Garlic is thought by many to be toxic to horses, however research looking into it found problems starting with a daily dose of > 0.2 g/kg. That would be 80 grams for a 400kg horse and one clove of garlic weighs around 6 grams. Also, once they fed over a cup a day of garlic the horses started refusing their feed with the garlic in it prior to reaching problematic levels. (3)

Fennel seed
Although many tout the anthelmintic properties of {Foeniculum vulgare} I couldn’t find any research on it. It is traditionally used to sooth sore stomachs by decreasing the formation of gas in the intestinal tract.

Sage
{Lamiaceae} is part of the mint family. It has also traditionally been labeled an anthelmintic, however I can’t find any research on it.

Oregano
{Origanum vulgare} is a genus of the mint family. It has been shown to have antimicrobial properties. Perhaps the best use of this herb is to use an oil extract externally.

Red Clover
{Trifolium pratense} is a very rich source of isoflavins, but I haven’t found any more information towards decreasing any parasitic infection.

—–

Conclusions:

Unfortunately there isn’t a lot of research on using herbs yet and many go by traditional beliefs, often that show some merit. There is one article I found investigating the efficacy of herbal dewormers on goats (4). It found no effect of the herbal dewormer to control gastrointestinal nematodes. However I don’t have access to that article and I don’t know which herbs they used, what doses, etc. I will add my conclusions as I do fecals and find out how my animals react to the herbal worming protocol. I will also do adjustments as I go! More to come.

One thing that I found to be cool is that even if I found pumpkin seeds not to have any effect, I would still feed them to the horses. We had a great pumpkin patch growing on one side of the manure pile!!

——

1. Burke, Wells, Casey, Miller. Garlic and papaya lack control over gastrointestinal nematodes in goats and lambs. JE.Vet Parasitol 2009 Feb 5;159(2):171-4. Epub 2008 Oct 15.

2. Nahed, Hoda, Yomna. Effects of garlic on albino mice experimentally infected with Schistosoma mansoni: A parasitological and ultrastructural study. Trop Biomed. 2009 Apr;26(1):40-50.

3. Pearson, Boermans, Bettger, McBride, Lindinger. Association of maximum voluntary dietary intake of freeze-dried garlic with Heinz body anemia in horses. Am J Vet Res. 2005 Mar;66(3):457-65.

4. Burke, Wells, Casey, Kaplan. Herbal dewormer fails to control gastrointestinal nematodes in goats. Vet Parasitol 160(1-2):168-70. Epub 2008 Nov 1.

——

(Note: Wormwood, Annis and fennel are the main herbs used in the preparation of absinthe, an alcoholic mixture which originated as a medicinal elixir in Switzerland and became, by the late 19th century, a popular alcoholic drink in France and other countries.)

They may be small, but ponies are tough and hardy and their nutritional requirements differ from a horse’s. Here’s how to feed your pony like a pony.

by Kerri-Jo Stewart as published in the current issue of Equine Wellness Magazine

Ponies aren’t horses. That means they can’t be fed the same way you would feed your horses. The obvious difference is in their smaller size, but ponies also tend to have more efficient metabolisms because they are designed to get maximum nutrition out of sparse coarse forage. They developed into tougher and more efficient keepers than most horses, and are adapted to conditions with harsher climates. Breeds such as Icelandic horses, miniatures, donkeys and mules are also hardier than horses and require their own specialized diets.

Basic requirements

Many horses only require a good quality forage, salt, minerals and constant access to clean water to maintain good condition. Ponies and easy keepers are best kept on lower quality forage (in terms of protein, energy and nutrient levels). A sparse pasture or quality grass hay is the major component of a pony’s diet. The pasture should be one in which the ponies have to work at finding the grass. They also require salt and mineral supplements (which can be free-fed in a loose crushed form), and access to clean fresh water.

Managing forage

An excellent idea for pasture is to try to reproduce conditions similar to those in which the breed originated. Add in dirt and/or gravel areas and sparsely use native grasses. All equids (horses, ponies, donkeys) prefer to eat small amounts of food steadily throughout the day. Six or seven hours of grazing per day on healthy dryland pasture can meet all their nutritional requirements.

It is far better for ponies to be outside on pasture, but when or where there is none available, hay becomes the main feed. Generally, forages may be fed based on weight, about one pound of forage for every 100 pounds of body weight. Many people successfully keep their ponies in a bare-land pasture and supplement with hay. Multiple feedings throughout the day help keep the pony’s digestive tract healthy. Get your hay analyzed, then add supplements to correct it to what is needed.

Some will add straw to a pony’s diet to increase bulk, but this should be limited to 10% of the total ration. Chaff is a mixture of chopped straw and added molasses for palatability. Like straw, it can be a good source of bulk but again should be limited to about 10% of the total ration. Feeding too much poor quality fill will deprive the pony of sufficient nutrients.

Pony power – supplements and concentrates

Ponies don’t usually require concentrates, and grain can present unnecessary amounts of sugar and starch. A hard working pony or lactating mare may need some extra supplementation, but first increase the amount of forage and then provide a higher quality forage or hay. Beet pulp, which is lower in energy than grain, can be a good addition. If more energy is required, some oil can be added to top up the pony’s diet. If a hard working pony needs concentrates, a ratio of no more than 30% concentrates to 70% forage is recommended.

Most commercial concentrates are designed for horses and will often provide insufficient nutrition at the small serving sizes needed for ponies. The added nutrients are too dilute for the amount required in smaller feedings. If a pony requires concentrates, feed and supplements designed especially for ponies should be used. These feeds may be referred to as pony mix or “lite” feed. If the pony’s coat starts to lose condition, she may need a protein supplement. Soybean meal can provide good quality protein without adding calories.

The downside of diets

We know being overweight is not beneficial for any animal and leads to a variety of problems. However, putting any animal on a feed reduced diet isn’t the answer and could create a situation in which the pony is being starved of nutrients. Caloric restriction, as well as not being able to feed for a sufficient time during the day, leads to problems that often manifest as behavioral issues. Instead, feed a good low quality hay throughout the day and increase the pony’s exercise program.

Keeping track

It is important to track your pony’s condition carefully. If you are unsure they are the correct weight, check them against a body condition scale. You can also measure their “heart girth” with a tape measure. In general, 30″ corresponds to about 70 pounds. Multiply every additional inch by 13 pounds and add it to the original 70 pounds.
Ponies are tough little animals. They have their own requirements and thrive in conditions similar to those they evolved for. Otherwise, they may require more management and their caretakers may need some help ensuring they are getting sufficient nutrients. It’s always worth getting your pasture and hay tested so you can balance your pony’s rations. Keeping them on a natural healthy diet and ensuring they get lots of exercise means they will stay happy and healthy.

A sparse pasture or quality grass hay is the major component of a pony’s diet.
Most commercial concentrates are designed for horses and will often provide insufficient nutrients at the small serving sizes needed for ponies.

Kerri-Jo Stewart has a masters from the University of Guelph in equine physiology and nutrition. She lives with her family in Maple Ridge, has Akhal-Teke horses and does equine photography. You can find more about her at http://Argamak.ca.

I think this is a great idea!! A perfect way to feed grass all year:

Check out Fodder Solutions!

Humm, now to figure out how to do some hydroponics!!

You can now test your racehorses for speed through Equinome. They have developed a genetic test for Thoroughbreds for the C:C (short), C:T (middle) and T:T (long) genes.

C:C -likely to be a fast, early maturing horse that performs well as a two-year-old. Average best distance – 6.5 f (1300 m)

C:T -mixture of speed and stamina and is the most versatile in terms of distance. A C:T horse can perform well as a two-year-old, but is best suited to races between 7 – 12 f (1400 – 2400 m).

T:T -best suited to races greater than 1 mile that require stamina. T:T horses are later maturing and do not perform optimally as two-year-olds. Average best distance – 11.1 f (2230 m)

The research is published in an open access journal:
A Sequence Polymorphism in MSTN Predicts Sprinting Ability and Racing Stamina in Thoroughbred Horses, Hill et al., PLos ONE, Vol 5.1, Jan 2010.

Abstract
Variants of the MSTN gene encoding myostatin are associated with muscle hypertrophy phenotypes in a range of mammalian species, most notably cattle, dogs, mice, and humans. Using a sample of registered Thoroughbred horses (n = 148), we have identified a novel MSTN sequence polymorphism that is strongly associated (g.66493737C.T, P = 4.8561028) with best race distance among elite racehorses (n = 79). This observation was independently validated (P = 1.9161026) in a resampled group of Thoroughbreds (n = 62) and in a cohort of Thoroughbreds (n = 37, P = 0.0047) produced by the same trainer. We observed that C/C horses are suited to fast, short-distance races; C/T horses compete favorably in middle-distance races; and T/T horses have greater stamina. Evaluation of retrospective racecourse performance (n = 142) and stallion progeny performance predict that C/C and C/T horses are more likely to be successful two-year-old racehorses than T/T animals. Here we describe for the first time the identification of a gene variant in Thoroughbred racehorses that is predictive of genetic potential for an athletic phenotype.

You can upload the article here.

Myostatin (GDF-8) is a member of the transforming growth factor beta superfamily and the encoding gene (MSTN) is thought to contribute to muscular hypertrophy in many species, including dogs (shown by speed in whippets) and cows (increased muscle mass for greater beef output). It was shown to be essential for proper regulation of skeletal muscle mass in mice. It seems to control the amount of muscle mass through hyperplasia, an increase in the amount of muscle fibers (versus an increase in the individual diameter of the fibers).

Preliminary study of jointed snaffle vs. crossunder bitless bridles: Quantified comparison of behaviour in four horses. W. R. Cook and D. S. Mills, Equine Veterinary Journal (2009) 41(1)

Abstract:
The study tested the null hypothesis that if a horse is ridden in a snaffle bridle and then a crossunder bitless bridle, there will be no change in its behaviour. It was predicted that there would be change and that behaviour would improve when bitless. Four horses, none of which had ever been ridden in a crossunder bitless bridle, were ridden through two 4-min, exercise tests, first bitted then bitless. An independent judge marked the 27 phases of each test on a 10-point scale and comments and scores were recorded on a video soundtrack. The results refuted the null hypothesis and upheld the predictions. Mean score, when bitted, was 37%; and through the first 4 min of being bitless, 64%. A binomial probability distribution suggested that the results were significantly different from random effects. All 4 horses accepted the crossunder bitless bridle without hesitation. Further studies are warranted and it is hoped that others will build on this new field of investigation. The authors are of the opinion that the bit can be a welfare and safety problem for both horse and horseman. Equestrian organisations that currently mandate use of the bit for competitions are urged to review their rules.

The entire article is available for free at IngentaConnect

Exerpt: Discussion
While the binomial probability distribution provides strong evidence to suggest that the results are not random, this calculation assumes that the tests are independent and that performance in the second test is not affected by performance in the first test. It is not known for certain that this assumption holds, though, for reasons given below, the authors believe this is unlikely. The strength of the finding provides sufficient evidence to warrant further investigation in a larger sample size, accommodating for potential experimental limitations and allowing for a more robust statistical analysis.

The possibility of an order effect (due to all horses receiving the bitless bridle second) deserves consideration. That improved behaviour could be attributed to the horses being better warmed-up for the second test can be refuted on the grounds that these horses had been in work throughout the day and were fully warmed-up at the time of the first test. That improved behaviour could be attributed to the greater familiarity of the horses with the test on the second occasion and not to the change of bridle is considered unlikely, given both the short latency and the magnitude of the improvement. In addition, such an explanation is not consistent with the sustained improvement that occurs with long-term usage of the crossunder bitless bridle observed by the authors in other contexts. Fatigue as an explanation for improved behaviour might also be considered but, in man, fatigue increases the frequency of error in sport performance and it seems unlikely that horses are any
different. The videotape showed that, when bitless, all 4 horses were more willing and alert than when bitted, so this too is inconsistent with a fatigue factor.

While there are some weaknesses in the objectivity of the methodology, for example the absence of ‘blinding’ by judge and rider, these are balanced to some extent by the presence of witnesses and the availability of a videotape recording. It is hoped that other researchers will build on this preliminary study, improve its design and conduct some of its many permutations. A recent review of tack-induced riding accidents lists over 200 negative behavioural responses and 40 different diseases caused by the bit (Cook 2009). Yet current competition rules for dressage, show hunter, hunter jumper classes and racing mandate the use of a bit. Applying the precautionary principle, there is strong evidence to suggest that an amendment of these rules is necessary. For the sake of both equine and human welfare a crossunder bitless option is recommended.

Endurance people take note! Your horses are affected by transportation. They are amazing creatures, but they do need time to recover fully following transportation. They also have increased susceptibility to disease in the 24 hours following transportation. Also, they are less stressed and less likely to get sick if their heads are not tied during transportation.

This topic is very important to me and I am republishing this post below again from my Teke blog. More and more evidence is continually coming out that shows that horses suffer stress from transportation, and even more so when their heads are tied up!

The Horse just published Transport and the Immune System, by: Rallie McAllister, MD. Their article is about Stull’s research article, Immunophysiological responses of horses to a 12-hour rest during 24 hours of road transport, Veterinary Record, also published in the Equine Veterinary Journal. Their study found that, “the immune systems of transported horses took about 24 hours to recover, making travel-stressed horses more prone to problems upon arrival at their destinations”.

“Horses normally don’t hold their heads above their withers for any length of time,” Stull explained. “An elevated head position not only increases the number of bacteria in the respiratory tract, it also suppresses the immune system, making horses more vulnerable to travel-related illnesses.”

Pleuropneumonia in Horses (Shipping Fever)

What is Pleuropneumonia?

Pleuropneumonia is inflammation and fluid build up both within the lung and pleura. The pleura is the space between the lungs and chest wall. Horses develop pleuropneumonia from contamination of the lower respiratory tract, their lungs, with bacteria that normally occurs in the upper respiratory tract, upper throat and nose (1).

How often do horses get it?

It is surprisingly common for horses to develop pleuropneumonia following shipping (2). One study found that 12% of horses developed respiratory ailments and up to 30-40% of horses were affected following air transportation (3a). Pneumonia, which developed following transport longer than eight hours, has resulted in death (3).

How can you tell?

Horses with pleuropneumonia may present with fever, depression, coughing, nasal discharge, and lack of appetite (3,4). Horses might not show clinical signs for two or three days following transport and so checking temperature is advisable up to a month after shipping (3). In addition, inflammation of the pleura is an extremely painful disease process creating pain between the ribs and sometimes causing a reluctance to walk (4).

What can I do once my horse is sick?

Treatment relies on long-term antibiotics, supportive therapy, and possibly drainage of the fluid from the thoracic cavity. There are numerous complications that can occur with pneumonia, including colic and founder along with anaerobic and other opportunistic infections. Treatment is usually more successful if no complications occur, although it still can take up to six months (4, 5). The death rate from pleuropneumonia has decreased because of aggressive treatments that are now available, however, it is probable that infected horses will never return to their athletic potential, or even their former use (6).

What can be done to avoid it?

1. Long distance transport:

Transport longer than 28 hours will likely be harmful in general due to increasing fatigue of the horses (7). Horses transported more than 500 miles were found to have a reduction in pulmonary macrophage function (responsible for clearance of small inhaled particles in the lung) for around three weeks (8). Transportation of any type, especially over long distances, has been thought to be the single most important predisposing factor for the bacterial contamination of the lower respiratory tract, which can develop into pleuropneumonia (6, 9).

2. Head height:

This contamination of the lung associated with transport happens when horses are unable to lower their heads. With their heads raised over an extended period there is a reduced opportunity for mucosal clearance leading to an increased opportunity for lower respiratory tract contamination (6). Basically it is the inability of horses to lower their heads during transport that is a primary cause of pleuropnemonia as they can’t clear mucous from their throats (6, 10). Horses confined with their heads elevated for 24 hours develop an accumulation of purulent airway secretions (and associated increased numbers of bacteria) in the lower respiratory tract and show a decrease in tracheal mucociliary clearance (11).

3. Air Exchange

To reduce the risk of respiratory tract infections in a stable it is advisable to have an air exchange three times an hour within the horses environment. When you have jet airplanes traveling at speed, air can be exchanged at three times per minute. In trucks and trailers there is also a frequent air exchange. The difficulty comes when a vehicle is stationary, as there is an immediate deterioration in the quality of the air (12).

4. Rest Stops

It was found to be very important to have long rest stops where horses are removed from the trailer, and the trailer is cleaned (13). The combination of the horses being able to get food and water while resting and traveling in a clean compartment reduced both transportation stress and respiratory infections.

5. Orientation

Some horses have been found to have strong preferences on which direction they face during transport, although backwards was usually preferred and found to be less physically stressful (13, 14). Horses may develop increased stress levels with a forward orientation, although that has not been found to initiate pleuropneumonia, except in cases where the horses heads were tied (15). Orientation is not what turns out to be an important factor, it is whether a horse is able to lower their head during transport that has been found to be the important factor in the development of respiratory disease.

References

1. FEI transport studies, USA 1999
2. Pub med list
3. AAEP Convention 2004: Controversies in Therapeutics–Immunomodulation by: Kimberly S. Brown, Editor. The Horse.com, February 14 2005 ,Article#5424
3a. Bonnie Rush, DVM, MS, Dipl. ACVIM, (AAEP) Convention in Denver, Colo., Dec. 4-8, 2004.
Catherine Kohn, VMD, PhD, Dipl. ACVIM, professor in the Department of Veterinary Clinical Sciences at The Ohio State University and a veterinarian involved with the United States Eventing Team, 2003 conference USDA.
4. Dehydration, stress, and water consumption of horses during long-distance commercial transport. T.H. Friend, Department of Animal Science, Texas A&M University, College Station.
5. Equine Respiratory Disease Part 2: The Lower Airway by: Michael Ball, DVM August 01 1998 Article # 533 TheHorse.com
6. Aust Vet J. 2000 May;78(5):334-8. Towards an understanding of equine pleuropneumonia: factors relevant for control. Racklyeft DJ, Raidal S, Love DN. Satur Veterinary Clinic, New South Wales.
7. J Anim Sci. 2000 Oct;78(10):2568-80. Dehydration, stress, and water consumption of horses during long-distance commercial transport. Friend TH. Department of Animal Science, Texas A&M University, College Station 77843-2471, USA. t-friend@tamu.edu
8. S. Hobo, et al. from the Equine Research Institute, Japan Racing Association, Tokyo, Japan, entitled “Effect of transportation on the composition of bronchoalveolar lavage fluid obtained from horses”
9. Aust Vet J. 1996 Feb;73(2):45-9. Effects of posture and accumulated airway secretions on tracheal mucociliary transport in the horse. Raidal SL, Love DN, Bailey GD. Department of Veterinary Pathology, University of Sydney, New South Wales.
10. Vet Rec. 1996 Jul 6;139(1):7-11. Effects of transporting horses facing either forwards or backwards on their behaviour and heart rate. Waran NK, Robertson V, Cuddeford D, Kokoszko A, Marlin DJ. Institute of Ecology and Resource Management, University of Edinburgh, School of Agriculture.
11. Acclimating Competition Horses by: Les Sellnow March 01 2006 Article # 6625 Des Leadon, MA, MVB, FRCVS, RCVS, TheHorse.com.
12. Improving Travel Conditions by: Les Sellnow October 01 2005 Article # 6176; theHorse.com.
13. J Comp Pathol. 2005 Feb-Apr;132(2-3):153-68. Effects of orientation, intermittent rest and vehicle cleaning during transport on development of transport-related respiratory disease in horses. Oikawa M, Hobo S, Oyamada T, Yoshikawa H. Equine Research Institute, Japan Racing Association, 321-4 Tokami, Utsunomiya, Tochigi 320-0856, Japan.
14. Equine Vet J. 1994 Sep;26(5):374-7. Body position and direction preferences in horses during road transport. Smith BL, Jones JH, Carlson GP, Pascoe JR.
15. Equine Vet J. 2002 Sep;34(6):550-5. Effects of cross-tying horses during 24 h of road transport. Stull CL, Rodiek AV. University of California, Davis, 95616, USA.

Hess et al. (1) conducted an interesting supplementation trial on horses during an endurance race with an international group*. They found that electrolytes with high Sodium and without Potassium, combined with a higher Calcium feed were advantageous to the horses and potentially decreases pull rates.

Clinical signs that are typically seen in horses when they are eliminated during endurance events are associated with increased neuromuscular excitability (which depends on membrane potentials), including slower heart rate recoveries, arrhythmia, muscle cramps, changes in intestinal motility and synchronous diaphragmatic flutter. These changes are related to the Potassium and Calcium levels in the horse’s blood.

The potassium in electrolytes may result in clinical signs related to neuromuscular excitability. During endurance exercise (speeds more than 4m/s) plasma Potassium levels increase, and they hypothesize that an increase in Potassium supplementation could be altering cellular membrane potentials. (Note: A recovery formula with potassium was supplied to the horses that were not supplemented with Potassium during the race and no differences in Potassium levels were found upon recovery.)

Plasma Calcium levels decrease with endurance exercise and horses generally become alkalotic. Diets typically fed to endurance horses have a high DCAB (from high amount of roughage), which may further reduce plasma Calcium levels. Calcium supplementation may help prevent hypocalcaemia.

Sodium supplementation is important in endurance racing as electrolyte losses through sweat can reduce the plasma volume and decrease thirst. Sodium losses are directly related to dehydration and its supplementation helps to restore thirst as it prevents a reduction in plasma osmolality.

The horses given the Potassium-free, Sodium-rich electrolytes had the better hydration rates both throughout and following the race.

Interestingly, for the 80 mile ride they found significant differences already at 27 km between the horses that completed and those eliminated at any point during the ride. Eliminated horses generally had a lower PCO2 (perhaps due to thermoregulation), higher plasma Potassium and lower Calcium concentrations, all of which can lead to increased neuromuscular excitability. Horses that were eliminated at this point had both higher Potassium and lower Calcium concentrations, which may have directly caused arrhythmia (as manifestations of neuromuscular hyperexcitability) that were seen.

At 48 km, the eliminated horses showed a trend towards lower chloride concentrations. Two horses at this point were eliminated for failure to recover heart rate, and one for colic. Clinically these signs can be related to dehydration. Low plasma concentrations of Chloride are related to dehydration through sweat loss.

Although there were no clinical signs related to increased neuromuscular excitability in any of the successful finishers, those without Potassium supplementation showed lower plasma Potassium concentrations, which could help maintain membrane potential and reduce neuromuscular excitability. Another thing to note is that with all groups on electrolyte supplementation, deficits in Sodium Chloride were still seen following the race. The study that attempted to formulate a total recovery formula but both hypernatraemia and hyperchloraemia were induced. But both of those formulas included Potassium supplementation. The ideal amounts of electrolytes for supplementation for endurance racing has not been determined, and an increase of Sodium supplementation without Potassium needs to be researched.

—————————————

1. Potassium-free electrolytes and calcium supplementation in an endurance race
Comparative Exercise Physiology 2008, 5(1); 33–41
TM Hess, KM Greiwe-Crandell, JE Waldron, CA Williams, MA Lopes, LS Gay, PA Harris and DS Kronfeld
(group includes researchers from *Virginia Polytechnic State University, Colorado State University, Rectortown Equine Clinic, Rutgers University, Universidade Federal de Vic in Brazil, and the Equine Studies Group, Waltham Centre for Pet Nutrition, in the UK.)

Abstract
Some of the clinical signs seen in horses during endurance races may result from increases in neuromuscular excitability and are related to plasma [Kþ] and [Caþþ]. The present study aimed to test the following hypotheses:
(1) Potassium supplementation will affect plasma [Kþ] and may result in clinical signs related to neuromuscular hyperexcitability during an 80km endurance ride.
(2) Plasma [Caþþ] will reflect dietary cation–anion balance (DCAB) and calcium intake. Feeding with a high DCAB and high dietary calcium content (1.5% total calcium of daily ration) diets would lead to higher plasma [Caþþ] during an endurance race than on feeding high DCAB diets with a moderate dietary calcium content (1% of total calcium of daily ration).
The current study was undertaken during the 80 km endurance research ride in 2002 in Virginia, USA. Forty volunteer rider–horse pairs participated in the race. During the race, electrolyte mixtures with (EM þ K) and without (EM 2 K) potassium were supplied to 18 and 22 horses, respectively. After the race, the horses receiving EM 2 K during the race were supplied with a recovery formula containing potassium (EM-REC). The horses were fed in addition to their own forage (hay and pasture) either their own commercial concentrate (CC; 1% calcium, n ¼ 11) or one of two research-supplied concentrates during 3 months preceding the research ride, one concentrate rich in sugar and starch (SS; 2% calcium, n ¼ 15) and the other rich in fat and fibre (FF; 2% calcium, n ¼ 14). Peripheral blood samples were taken the day before, within 3 min of the arrival at the vet checks at 27, 48 and 80 km, and after 3 h of recovery. Plasma samples were analysed for pH, haematocrit (Hct), [Naþ], [Kþ], [Cl2], [Caþþ], [Mgþþ], total protein (TP) and albumin [alb]. Effects of sampling times, treatments and interactions were evaluated by ANOVA in a mixed model with repeated measures and applied to the 25 horses that completed 80 km. Eliminated horses had their blood sampled before entering the elimination vet check and 3 h after elimination, and were compared with finishing horses by t-test. As the ride progressed, significant increases were found in plasma pH, [Naþ], ½PO2 4
, [TP], [alb], Hct and osmolality; and decreases in [Kþ], [Mgþþ], PCO2, [Caþþ] and [Cl2]. Horses supplied with potassium-free, sodium-rich electrolyte formulae (EM 2 K) had 12.5% lower (P ¼ 0.001) mean plasma [Kþ], 7.8% lower (P ¼ 0.024) TP and 8.4% lower (P ¼ 0.004) albumin at 80 km, and at 3 h after the race they had 6.8% lower (P ¼ 0.045) TP, when compared with EM þ K supplemented horses. Horses fed with SS and FF had higher [Caþþ] at 27 (P ¼ 0.027), 56 (P ¼ 0.006) and 80km (P ¼ 0.022) when compared with horses fed with CC. The lower [Kþ] in the EM 2 K group, and the higher [Caþþ] in the SS- and FF-supplemented horses may help prevent increases in neuromuscular excitability and related clinical signs. The lower TP and albumin indicate less dehydration in the EM 2 K group and could help prevent related disorders.

The dietary cation-anion difference (DCAD) of a feed can be used to characterize large animal diets. DCAD (also known as DCAB or dietary cation-anion balance) of the diet is a major determinant of blood SID as the strong ions enter the blood from the digestive tract (Riond 2000). DCAD is the difference between the strong base cations and strong acid anions:

DCAD = (Na+ + K+ + Ca2+ + Mg2+) – (Cl–+ SO42- + H2PO4-) mEq/kg DM
(Kronfeld 2001, Graham-Thiers et al. 1999)

DCAD affects systemic acid-base balance because it defines the overall net cation to anion content of the feed. The chemical components of the diet affecting acid-base status include the amount of protein, Cl-, P-, Na+, K+, Ca2+, and Mg2+. The ions present in diet only alter [SID]p if they are absorbed into the blood. Kronfeld (2001) allows for an assumption of a 100% absorption rate for monovalent ions and 50% for divalent ions. A common equation currently used is:

DCAD = (Na+ + K+) – Cl- mEq/

This DCAD equation takes into account the most readily absorbed ions with the greatest metabolic impact on acid-base balance (Baker 1991, 1998). It includes only monovalent dietary electrolytes, except for sulfur, and ions with a higher valence are ignored. Some studies include SO42- in the equation (Baker et al. 1998; Cooper et al 1998; Popplewell et al. 1993), however the contents of Ca2+, Mg2+ and SO42- in feed act to neutralize each other and have a variable and incomplete intestinal absorption (Spears et al. 1985). Baker and colleagues (1998) found that if SO42- was to be included in the DCAD equation it would need a modifying coefficient as it is not as acidogenic as Cl-. They also confirmed that Na+ and K+ have similar alkalogenic properties. H2PO4- is also left out of the equation, as it is a weak acid and exists in feed in low concentrations.

Mechanisms

A neutral DCAD, which doesn’t result in changes in acid-base status, can be between 250-300 mEq/kg of feed dry matter (DM) (Lindinger 2003). A DCAD of greater than 300 mEq/kg may result in an increased cation content of extracellular fluids, creating a systemic alkalosis, which increases the plasma pH and the concentrations of plasma Na+, HCO3-, PCO2 and Ca2+ balance, and decreases the [Cl-] (Baker 1993; Popplewell 1993). A DCAD of less than 250 mEq/kg may result in a metabolic acidosis, decreasing plasma pH, and the concentrations of plasma Na+, K+, Mg2+, HCO3-, PCO2 and increasing Cl-; as well as increasing the urinary excretion of K+, Na+ Cl- and Ca2+ (Topliff 1989, Baker et al. 1992, 1993, 1998; Mueller 1999, McKenzie 2002, 2003, Topliff 1989). Plasma pH and [HCO3-], and urine pH have been shown to increase in proportion to DCAD over a range of 0 to 407 mEq/Kg (Baker et al. 1992, 1998; Topliff et al. 1989).

When a high DCAD feed is consumed the high cationic and low anionic components result in increased cation content of extracellular fluids through absorption in the small intestine. With the continuation of a high DCAD diet the cations are accompanied by HCO3- and Cl-, which can produce a mild systemic alkalosis (Lindinger 2003).  Depending on diet composition, the blood bicarbonate level can be regulated in the intestine by increasing or decreasing the amount of alkali from pancreatic secretion. The liver and other metabolically active tissues then use the products of pancreatic secretion as substrates for generating acids or alkalis. Excess cations are excreted from the kidneys. Some H+ are also lost in feces.

McKenzie (2002, 2003) found that a high DCAD diet resulted in higher [Pi]p and lower [K+]p compared to a neutral diet, but that [Na+]p, [ Cl-]p and [Mg2+]p did not differ between horses consuming the neutral and high DCAD diets. Popplewell et al (1993) found that horses on a high DCAD diet had faster times in a standard anaerobic test (1.64 km) compared to those on a lower DCAD diet. Graham-Thiers et al. (2001) also found that horses on the higher DCAD diets were faster than those on a low DCAD diet (20 mEq/kg DM) and found no difference between the medium and high DCAD diets (125 – 350 mEq/kg). Although there is no consensus on whether a high DCAD diet will enhance performance in horses, the expectation is that it will help to offset or delay the acidic component of fatigue (Graham-Thiers et al. 2001).

A low DCAD diet produces a systemic acidosis which may lead to a negative calcium balance from increased Ca2+ loss through the urine due to and an overall weakening of the skeletal system (Wall et al.1992, Fressetto et al. 2001, Sebastian et al.1994, Baker et al.1998). However, Cooper and colleagues (2000) found that weanling horses consuming highly anionic diets were able to make up for an increased urinary excretion of Ca2+, and growth performance was not affected by DCAD. More research is needed to look into the effect of DCAD and Ca2+ with respect to growth and performance specifically to horses.

Feed Components

Grains have low cation content (Na+ + K+ + Ca2+) and high anion content (Cl-), which results in a low DCAD, while forages generally have higher levels of cations with an increased DCAD. The NRC (1989) rated corn with a DCAD at about 58 mEq/kg dry matter (DM) and oats at 73 mEq/kg DM, as compared to alfalfa at 323 mEq/kg DM and Bermuda grass hay at 427 mEq/kg DM. Dietary protein and fat have also been found to affect acid-base status, however, with fat, a change is exhibited only during exercise.

Grain

Originally it was thought that the metabolic acidosis following ingestion of a high grain meal was due to lactic acid production from the digestion of starch (Ralston 1993). DCAD was not considered. The current thinking, however, is that the acidosis is due to the low levels of cations typically found in cereal grains contributing to a low DCAD (1999 Mueller). Mueller (1999) found no significant differences in plasma pH between both starch sources and starch intake.

When grains are fed in high concentration they tend to cause a metabolic acidosis (Roby et al. 1987; Abu Damir et al. 1990; Ralston 1994). Many foals and performance horses are fed a high grain ration, which contains a low DCAD (<100 mEq/L), consisting of equal to or greater than 50% of their total intake. A chronic metabolic acidosis may increase the incidence of developmental orthopedic diseases, including stress fractures in athletic horses from a decreased bone mineral content. For example, Jones (1989) found that 58.1% of 2-yr old racehorses experienced an injury. Similarly, Fressetto et al. (2001) found that a high DCAD diet, often with a deficiency of K+, caused growth retardation in children and decreased muscle and bone mass in adults. In these cases, it may be the DCAD and not the actual food source that is responsible for acid-base changes. Hence a systemic acidosis could be corrected by increasing the DCAD in a high starch diet (Mueller 2001).

Forages

A diet consisting of only forage ration seems to have a lesser immediate effect on acid-base balance when compared to eating grain rations. Ralston (1993) fed hay only and found its digestion had minimal effects on plasma pH during the first hour of feeding. However, they did not extend the testing time out to when more effects from feeding hay would have been seen. Kerr and Snow (1992) found no change in PCV, [PP] or [K+] after a morning feed of 1.8 kg of a commercial cube diet (composed of high fiber, low starch, no cereal grain). It was not until following a second feed of the same diet at noon and during a feeding of 2.7 kg cubes with 5.5 kg of hay at 1700 hr that there was an increase in both the PCV and [PP] and a decrease in [K+]p.

Combination Diets

Stutz and colleagues (1992) fed a ratio of 60% concentrate: 40% Bermuda grass hay with four diets of different DCAD measurements and took hourly jugular venous blood samples for 17h. Horses were fed at t=0 h and 12h. All diets exhibited a maximal decrease in pH and increased PCO2 at 1h post feed, with a return to baseline values over the following 12h. The plasma [HCO3-] decreased for the first 3-h following feeding and then also returned to baseline values over the next 5-9 h.

Ralston (1993) compared two meals of differing grain: forage ratios that were controlled for DCAD, protein and caloric content. The first was at 60% grain: 40% forage, and the second was with 10% grain: 90% forage. A decrease in pH was seen consistently at 30-60 min after a meal of grain. However, the drop was fairly minimal, and though statistically significant it was perhaps not physiologically significant. pH remained depressed for up to 2-3 h if no other feed was available and was reflected in a decrease in urine pH 3-4 hours later. Fecal pH was lower in horses fed 50% grain versus those fed hay only. Their conclusion was that the amount of starch in the diet, and not the DCAD, which caused the different acid-base responses following ingestion.

However, to illustrate that the DCAD does cause acid-base changes, Mueller and colleagues (1999) used 3 high DCAD and 3 low DCAD diets, with starch comprising 45-49% of each diet. They found that high starch diets had no effect on plasma acid-base balance, regardless of source (corn, oats or alfalfa). They concluded that the acidogenic effects of a high starch source were overcome by increasing the DCAD of that feed source.

Ralston and colleagues (1997) manipulated the feed DCAD with the addition of 1% NaHCO3 to a 50:50 ratio grain and alfalfa diet. This reduced the decrease in the resultant post-feeding plasma pH and increased blood HCO3-. Baker et al. (1998) also found that feeding additional strong cations in bicarbonate or citrate form to increase the diet DCAD, increased urine and plasma pH and blood bicarbonate levels. Fressetto et al. (2001) also found that using small amounts of exogenous base, potassium bicarbonate (KHCO3), to neutralize the diet improved Ca2+ and K+ balances, reduced bone absorption rates and improved the nitrogen balance. Furthermore, Sebastian (1994) neutralized blood acid-base composition with KHCO3 added to the diet, and found significant improvements in health.

These studies show that although the amount of starch has an affect on acid-base balance through the DCAD of the feed, it is possible to minimize that effect by manipulating the DCAD.  Although horses seem to be able to compensate for a high anionic diet, it is thought that a higher DCAD diet is more beneficial to the overall health of a horse.
The control of DCAD in feed, specifically to maintain high DCAD levels, is important to have the most advantageous diet for horses to allow horses to perform at their highest capabilities.

Protein

Some studies have found that dietary protein has an effect on plasma acid-base status of horses. Protein is acidogenic as it contains sulfur and phosphorus that oxidize to sulfate (SO42-) and phosphate (Pi), which become elevated in plasma. Graham-Thiers et al (1999, 2001) found that plasma SID and pH were higher and PCO2 was lower in horses that were fed less protein. However, the effects on acid-base balance may be due to the low DCAD of the high protein diet. Greppi et al (1996) found no differences in plasma biochemistry between feeding 3 different levels of protein over 27 days at 713g crude protein (CP) (7.4% of diet), 824g CP (8.2%), and 962g CP (9.8%). Graham-Thiers et al (1999, 2001) also used diets at 7.5% CP and 14.5% CP so perhaps Greppi et al (1996) did not sufficiently vary the amount of CP or it is the overall percentage of the CP in the diet that elicits a response. Although these studies suggest that a low protein diet may have an alkalizing acid-base response, those effects are so small that they are of questionable physiological significance.

Fat

There appears to be no influence of fat supplementation on acid-base status at rest (Graham-Thiers et al. 2001, Kronfeld 2001). However, with exercise it may spare protein during energy demanding states, for example, fat adaptation influenced acid-base responses to repeated sprints (Graham-Thiers et al. 2001). This effect is thought to be largely due to limiting the increase in PCO2 in venous blood (Kronfeld et al. 1998). With high fat diet supplementation (10% of diet intake), high intensity exercise fat adaptation increased plasma [Lac-] and decreased acidosis (Custalow et al. 1993; Taylor et al. 1993; Ferrante et al. 1994).

————————

This article is an excerpt from A Summary of the Effects of Feeding and Daily Variation on Acid-Base Status in Resting Horses. The complete article is available for download and this portion is provided here to attempt to explain DCAB, which I think is important for all competitive riders to understand. Below is the reference list. If you have any updated information I would love you to send it to me!

————————

Reference List

(1989). NRC: Nutrient Requirements of Horses., 5 ed. National Academy Press, Washington, DC.
(2000). Effect of dietary cation-anion difference on mineral balance, serum osteocalcin concentration and growth in weanling horses. J Equine Vet Sci 20.
Abu Damir (1990). Anim Prod 51, 547.
Baker LA, Topliff DR, Freeman DW, & Breazile JE (1992). Effect of dietary cation-anion balance on acid-base status in horses. J.Equine Vet Sci 12, 160-163.
Baker LA, Wall DL, & Topliff DW (1993). Effect of dietary cation-anion balance on mineral balance in anaerobically exercised and sedentary horses. J Equine Vet Sci 13, 557-561.
Baker LA, Wall DL, Topliff DR, Freeman DW, Teeter RG, Breazile JE, & Wagner DG (1993). Effect of dietary cation-anion balance on mineral balance in anaerobically exercised and sedentary horses. Equine Nutrition and Physiology Society, 13th Symposium 13, 557-561.
Baker LA, Topliff DR, Freeman DW, Teeter RG, & Stoecker B (1997). The comparison of two forms of sodium and potassium and chloride versus sulfur in the dietary cation-anion difference equation: effects on acid-base status and mineral balance in sedentary horses. Equine Nutr and Physiol Society Annual Symposium 18, 389-395.
Baker LA, Topliff DR, & Freeman RG (1998). The comparison of two forms of sodium and potassium, and chloride versus sulfur in the dietary cation-anion difference equation: Effects on acid-base staus and mineral balance in sedentary horses. J Equine Vet Sci 18, 389-396.
Block, E. (1993). Manipulation of Dietary Cation-Anion Difference on Nutritionally Related Production Diseases, Productivity, and Metabolic Responses of Dairy Cows. J Dairy Sci 77, 1437-1450.
Cooper SR, Kline KH, Foreman JH, & Frey LP (1998). Effects of dietary cation-anion balance on pH, electrolytes, and lactate in Standardbred horses. J Equine Vet Sci 18, 662-666.
Custalow SE, Ferrante PL, Taylor LE, Moll HD, Meacham TN, Kronfeld DS, & Tiegs W (1993). Lactate and glucose responses to exercise in the horse are affected by training and dietary fat. 13th Equine Nutrition and Physiology Symposium Proceedings, U.Florida.
Dunnett, M., Harris, R. C., Dunnett, C. E., & Harris, P. A. (2002). Plasma carnosine concentration: diurnal variation and effects of age, exercise and muscle damage. Equine Vet J Suppl 283-287.
Ferrante PL, Kronfeld DS, Taylor LE, & Meacham TN (1994). Plasam [H+] responses to exercise in horses fed a high-fat diet and given sodium bicarbonate. J Nutr 124, 2736s-2737s.
Frassetto L, RC Morris Jr., DE Sellmeyer, K Todd, & A Sebastian (2001). Diet, evolution and aging. Eur J Nutr  40, 200-213.
Graham-Thiers PM, Kronfeld DS, & Kline KA. (1999). Dietary protein influences acid-base responses to repeated sprints. Equine Exercise Physiology 5. Equine Vet J Suppl 30, 463-467.
Graham-Thiers PM, Kronfeld DS, Kline KA, & Sklan DJ (2001). Dietary protein restriction and fat supplementation diminish the acidogenic effect of exercise during repeated sprints in horses. J Nutr 131, 1959-1964.
Greppi GF, Casini L, Gatta D, Orlandi M, & Pasquini M (1996). Daily fluctuations of haematology and blood chemistry in horses fed varying levels of protein. Equine Vet J 28, 350-353.
Jansson, A. & Dahlborn, K. (1999). Effects of feeding frequency and voluntary salt intake on fluid and electrolyte regulation in athletic horses. J Appl.Physiol 86, 1610-1616.
Jansson, A., Lindholm A, Lindberg JE, & Dahlborn, K. (1999). Effects of potassium intake on potassium, sodium and fluid balance in exercising horses. Equine Vet J Suppl 30, 412-417.
Jones WE (1989). Racetrack breakdown epidemiology. Equine Vet.Data 10, 190-191.
Kerr MG & Snow DH (1982). Alterations in haematocrit, plasma proteins and electrolytes in horses following the feeding of hay. Vetrinary Record 110, 538-540.
Kronfeld DS, Custalow SE, Ferrante PL, Taylor LE, Wilson JA, & Tiegs W (1998). Acid-base responses of fat adapted horses: relavence to hard work in the heat. Appl Anim Behav Sci 59, 61-72.
Kronfeld DS (2001). Body fluids and exercise: influences of nutrition and feeding management. Veterinary Review 21, 417-428.
Lindinger MI. Acid-Base physiology during exercise and in response to training. Equine Sports Medicine and Surgery. 2003 (In Press)
McKenzie, E. C., Valberg, S. J., Godden, S. M., Pagan, J. D., Carlson, G. P., MacLeay, J. M., & DeLaCorte, F. D. (2002). Plasma and urine electrolyte and mineral concentrations in Thoroughbred horses with recurrent exertional rhabdomyolysis after consumption of diets varying in cation-anion balance. Am.J Vet Res. 63, 1053-1060.
Mongin P (1981). Recent advances in dietary cation-anion balance: applications in poultry. Proc Nutr Soc 40, 285-294.
Mueller, R. K., Topliff DR, Freeman DW, MacAllister C, Carter SD, & Cooper SR. Effect of varying DCAD on the acid-base status of mature sedentary horses with varying starch source and level of intake. Animal Science Research Report.  1999. Oklahoma State University, USA.  Ref Type: Report
Mueller, R. K., S.R.Cooper, D.R.Topliff, D.W.Freeman, C.MacAllister, & S.D.Carter (2001). Effect of dietary cation-anion difference on acid-base status and energy digestibility in sedentary horses fed varying levels and types of starch. Journal of Equine Veterinary Science 21, 498-502.
Popplewell JC, Topliff DR, Freeman DW, & Breazile JE (1993). Effects of dietary cation-anion balance on acid-base balance and blood parameters in anaerobically exercised horses. Proc 13th Equine Nutr and Physiol Symp Gainesville, Fl. 13, 191.
Ralston SL (1994). Equine Practice 16, 10.
Ralston SL (1997). Bicarbonate supplementation of young horses fed high grain rations. Proc fourteenth Equine Nutr Physiol Symp Ontario CA. 4.
Remer T (2001). Influence of nutrition on acid-base balance – metabolic aspects. Eur J Nutr 40.
Riond, J. L. (2001). Animal nutrition and acid-base balance. Eur.J Nutr. 40, 245-254.
Roby KA (1987). Am J Vet Res 48, 1012.
Sebastian, A., Harris, S. T., Ottaway, J. H., Todd, K. M., & Morris, R. C., Jr. (1994). Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate. N.Engl.J Med. 330, 1776-1781.
Stutz WA, Toppliff DR, Freeman DW, Tucker WB, Breazile JE, & Wall DL (1992). Effect of dietary cation-anion balance on acid-base status on blood parameters in exercising horses. J Equine Vet Sci 12, 164.
Taylor LE, Ferrante PL, Meacham TN, Kronfeld DS, & Tiegs W (1993). Acid-base responses to exercise in horses trained on a diet containing added fat. 13th Equine Nutrition and Physiology Symposium Proceedings, U.Florida.
Topliff DR, Kennerly MA, & Freeman DW (1989). Changes in urinary and serum calcium and chloride concentrations in exercising horses fed varying cation-anion balances. Proc 11th Equine Nutr Phsiol Symp 1-4.
Wall DL, Topliff DR, Freeman DW, Wagner DG, & Breazile JE (1991). Effects of dietary cation-anion balance on urinary mineral excretion in exercised horses. J Equine Vet Sci 12, 168.
Yashiki K, Kusunose R, & Takagi S (1995). Diurnal variations of blood constituents in young thoroughbred horses. J Equine Sci 6, 91-97.

Neilsen and Spooner of Michigan State did a post hoc study of research looking at changes in bone as a result of either nutrition or exercise. The interest in decreasing skeletal injury in horses is of course of great practical importance to horse owners and trainers. They found that it is exercise that causes improvements in bone throughout the literature.

The studies of dietary treatments reviewed generally failed to elicit responses in bone metabolism or markers of bone quality in horses (finding high variability and low repeatability). Nutrients evaluated increased and varying concentrations of Vitamin D, dietary protein, calcium, lysine and threonine, phosphorus, trace minerals, supplemental manganese, and inorganic mineral supplementation. Although many of the nutrients were found to increase growth rates they did not elicit changes in the bone. Even when looking at results from the other way low starch concentrates fed in sufficient amounts to reduce growth rate in yearlings did not have an effect on bone minerals deposition.

All the exercise studies reviewed, except one involving lunging only, showed improvement in bone quality markers with exercise. Interestingly, the two studies comparing stabled to pastured horses showed a decrease in bone quality with the stalled horses. The bone quality changed quickly as the load requirements changed for the horses.

Their conclusion from looking at the research was that, “The horse appears capable of altering its absorption of nutrients to maintain bone health to a much greater degree than its ability to maintain bone strength if not provided with adequate exercise”.

————————————

Small changes in exercise, not nutrition, often result in measurable changes in bone
Comparative Exercise Physiology 2008, 5(1); 15–20
BD Nielsen* and HS Spooner
Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA
* Corresponding author: bdn@msu.edu

Abstract
Skeletal injuries in the equine athlete are a tremendous concern with both economic and animal welfare implications. As a result, much research has focused on improving bone quality through nutritional and exercise interventions. With the recent utilization of biochemical markers, changes in bone metabolism can be monitored. This study examined and compared the response of bone markers and estimates of bone mineral content, in studies with nutritional interventions, with those utilizing exercise interventions. The post hoc analyses suggest that nutritional interventions result in less change to bone markers and bone mineral content than exercise treatments. Of the bone markers examined, osteocalcin correlates most strongly to estimates of bone quality while keratin sulphate, an indicator of cartilage turnover, showed the least correlation. Comparing the results of this study with other published studies, similar findings were observed, suggesting that small alterations in exercise play a greater role in affecting measurable changes in bone metabolism and quality of the equine athlete than do small changes in nutrition.

Here is an abstract of research from Northern Arizona University finding that stallions were faster than both mares and geldings. Looking at the results for Thoroughbred, the stallions were lengths ahead of the mares at the 1600m (or less) races and there was twice as much difference between them at races over 1600m.

Do racehorses and Greyhound dogs exhibit a gender difference in running speed?

Equine and Comparative Exercise Physiology (2007), 4:135-140 Cambridge University Press
Department of Biological Sciences, Northern Arizona University, Box 5640, Flagstaff, AZ 86011, USA

Abstract

At any level of competition, men run faster than women. Consequently, a male speed advantage is often presumed for other species. This assumption was tested in two animals bred for speed: horses and dogs. Results from Thoroughbred (TB), Standardbred (STB) and Greyhound (GH) races were analysed by ANOVA to compare the speeds of victorious males, neutered males (TB and STB only) and females. Separate analyses were run for shorter (TB: ≤ 1609 m, GH: 503 m) and longer (TB: >1609 m, GH: 603.5 m) TB and GH races. All STB races (trotters and pacers) were 1609 m. In TB races, intact males were 0.7% faster than females at ≤ 1609 m (n = 305; P < 0.01) and 1.4% faster at >1609 m (n = 194; P < 0.01). The speed of neutered males was equivalent to that of females at both distances. Gender accounted for 3.8 and 10.7% of the variance in speed at short and long distances, respectively. In STB pacers, intact males were 1.5% faster than females and gender accounted for 10.1% of the variance in speed (n = 96; P < 0.01). Gender was not a significant predictor of STB trotter (n = 95) or GH speed at 503 m (n = 146) or 603.5 m (n = 23). In conclusion, gender has a significant effect on speed of TBs and STB pacers. Although the effect size is small, it may be significant for racing; in a 7 furlong (1408 m) TB race, the 0.7% difference translates to an advantage of several lengths.

There is a paucity of scientific data on massage therapy (Lovas et al. 2002). The few studies performed using objective measurements have methodological flaws. Scientific evidence currently does not support nor refute claims made by massage advocates. Although many studies find that massage may be beneficial, researchers also discuss the lack of objective measures and scant evidenced based aspects of massage therapy and state that further investigation is required (Oppel 2000; Sedergreen 2000; Preyde 2000). Fontanarosa and Lundberg (1998) discuss the need for convincing data on safety and therapeutic efficacy and comment on problems with methodological quality in previous research. Tiidus (2000) noted that there is virtually no scientific information available on equine massage. His own studies on humans with DOMS found that massage does not alter whole limb blood flow. Importantly however, he used a Doppler ultrasound technique that did not measure localized blood flow specific to one muscle being massaged, and therefore failed to isolate the effect of massage. Ernst’s (1998) meta-analysis on massage therapy found that most of the research conducted to date had serious methodological flaws resulting in conflicting results. However, his conclusion was that most research suggests that post-exercise massage may alleviate symptoms of DOMS.

Increased blood flow to injured tissue provides oxygen and nutrients and removes breakdown products from the muscle (Newman 2002; McAllister 1995). However, attempts to demonstrate increased skeletal muscle blood flow during local skeletal muscle injury have failed primarily due to methodological errors because whole limb measurements have been made during the study of localized tissue responses. Whole limb measurement techniques lack sensitivity in the studies examining the effects of massage on muscle injury. MT validation for healing tissue requires measuring localized blood flow change to the muscle being massaged.

Delayed onset muscle soreness (DOMS) peaks 24 to 48-hours following unaccustomed exercise (Vickers 2001). DOMS is due to the physical and biochemical muscle fiber degradation that occurs during and after the activity and is followed by a two to three-week repair period. During the repair phase there is a proliferation of myogenic stem cells and increased stem cell activation resulting in the differentiation of new muscle fibers. Massage therapy (MT) is an accepted and used primary treatment option for DOMS. However, MT lacks validity as a medical modality because its effects have yet to be scientifically established.

———-

References

Beaton, L. J., Tarnopolsky, M. A., & Phillips, S. M. (2002). Variability in estimating eccentric contraction-induced muscle damage and inflammation in humans. Can J Appl Physiol 27, 516-526.

Bischoff, R. (1994). The satellite cell and muscle regeneration. In Myology, ed. Engel AG, a. F.-A. C., pp. 97-118. McGraw-Hill, New York.

Bossen, E. (2000). Muscle biopsy. In Diseases of skeletal muscle, ed. Wilkins, pp. 333-348. Lippincott Williams, Philadelphia.

Boushel, R. & Piantadosi, C. A. (2000). Near-infrared spectroscopy for monitoring muscle oxygenation. Acta Physiol Scand . 168, 615-622.

Ciurczak, E. W. & Drennen, J. K. (2002). Pharmaceutical and Medical Applications of Near-Infrared Spectroscopy Marcel Dekker,Inc., New York.

Ernst, E. (1998). Does post-exercise massage treatment reduce delayed onset muscle soreness? A systematic review. Br.J.Sports Med. 32, 212-214.

Fontanarosa, P. B. & Lundberg, G. D. (1998). Alternative medicine meets science. JAMA 280, 1618-1619.

Hawke, T. J. & Garry, D. J. (2001). Myogenic satellite cells: physiology to molecular biology. J.Appl.Physiol 91, 534-551.

Lovas, J. M., Craig, A. R., Raison, R. L., Weston, K. M., Segal, Y. D., & Markus, M. R. (2002). The effects of massage therapy on the human immune response in healthy adults. Journal of Bodywork and Movement Therapies 6, 143-150.

Mancini, D. M., Bolinger, L., Li, H., Kendrick, K., Chance, B., & Wilson, J. R. (1994). Validation of near infrared spectroscopy in humans. J.Appl.Physiol 77, 2740-2747.

McAllister, R. M., Delp, M. D., Thayer, K. A., & Laughlin, M. H. (1995). Muscle blood flow during exercise in sedentary and trained hypothyroid rats. Am.J Physiol 269, H1949-H1954.

Newman, J. M., Rattigan, S., & Clark, M. G. (2002). Nutritive blood flow improves interstitial glucose and lactate exchange in perfused rat hindlimb. Am.J Physiol Heart Circ.Physiol 283, H186-H192.

Oppel, L. (2000). Is massage therapy genuinely effective?  CMAJ. 163, 953-954.

Preyde, M. (2000). Effectiveness of massage therapy for subacute low-back pain: a randomized controlled trial. CMAJ. 162, 1815-1820.

Pringle, J., Roberts, C., Art, T., & Lekeux, P. (2000). Assessment of muscle oxygenation in the horse by near infrared spectroscopy. Equine Vet.J. 32, 59-64.

Ramey, D. W. T. P. M. (2002). Massage Therapy in Horses: Assessing Its Effectiveness from Empirical Data in Humans and Animals. COMPENDIUM on Continuing Education for the Practicing Veterinarian 24, 418-423.

Sahlin, K. (1992). Non-invasive measurements of O2 availability in human skeletal muscle with near-infrared spectroscopy. Int.J.Sports Med. 13 Suppl 1, S157-S160.

Sedergreen, C. (2000). Is massage therapy genuinely effective? CMAJ. 163, 953-954.

Shoemaker, J. K., Tiidus, P. M., & Mader, R. (1997). Failure of manual massage to alter limb blood flow: measures by Doppler ultrasound. Med.Sci.Sports Exerc. 29, 610-614.

Sowa, M. G. e. al. (1997). Noninvasive assessment of regional and temporal variations in tissue oxygenatoin by near-infrared spectroscopy and imaging. Appl.Spectrosc. 51, 143.

Taylor, D. E. & Simonson, S. G. (1996). Use of near-infrared spectroscopy to monitor tissue oxygenation. New Horiz. 4, 420-425.

Tiidus, P. M. (1999). Massage and ultrasound as therapeutic modalities in exercise-induced muscle damage. Can.J.Appl.Physiol 24, 267-278.

Tiidus, P. M. (2000). A Review of Human Massage Therapy: Assessing Effectiveness Primarily from Empirical Data in the Human Species. American Association of Equine Practitioners, AAEP Proceedings 46, 302-305.

Tiidus, P. M. & Shoemaker, J. K. (1995). Effleurage massage, muscle blood flow and long-term post-exercise strength recovery. Int.J.Sports Med. 16, 478-483.

Vickers, A. J. (2001). Time course of muscle soreness following different types of exercise. BMC.Musculoskelet.Disord. 2, 5.Part F: Facilities and Resources

The type of feed the horse eats is what determines what fuel is available for the horse to use during exercise. So it is important to figure out the optimal diet for your horses. Although there has been research showing the benefits of fat supplementation over feeding grain in equine diets, many people still prefer to add grain to the diet thinking it is better for their horses. This paper is one of the more recent showing that fat supplemented horses used less glucose during endurance exercise than the horses whose diet was supplemented with sweet feed. That means that that their limited glycogen stores are used up faster than when they are fed the higher fat diet. So, it is the horses fed higher fat without the grain whose energy systems will benefit in endurance exercise. And on top of what to feed for best performance is that the traditional high grain diet may be a root cause of many problems, including laminitis, obesity, diabetes and tying up.

Dietary Energy Source Affects Glucose Kinetics in Trained Arabian Geldings at Rest and during Endurance Exercise

Kibby H. Treiber,3* Ray J. Geor,3 Raymond C. Boston,4 Tanja M. Hess,3 Pat A. Harris,5 and David S. Kronfeld3

3 Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061; 4 Department of Clinical Sciences, New Bolton Center, Kennett Square, PA 19348; and 5 Equine Studies Group, WALTHAM Centre for Pet Nutrition, LE14 4RT Melton Mowbray, UK

J. Nutr. 138: 964–970, 2008

Abstract

Advances in modeling and tracer techniques provide new perspective into glucose utilization and potential consequences to health or exercise performance. This study used stable isotope and compartmental modeling to evaluate how adaptation to a feed high in sugar and starch (SS) compared with a feed high in fat and fiber (FF) affects glucose kinetics at rest and during exercise in horses. Six trained Arabians adapted to each feed underwent similar tests at rest and while running ;4 m/s on a treadmill. For both tests, horses received 100 mmol/kg body weight [6,6-2H]glucose through a venous catheter. Circulating tracer glucose was described for 150 min by exponential decay curves and compartmental analysis. All parameters of glucose transfer increased with exercise (P # 0.004). Compared with FF horses, SS horses had higher circulating glucose (P ¼ 0.022) and fractional glucose transfer rates (min 21 ) at rest (P ¼ 0.055). Exercise increased glucose irreversible loss (mmol/min) more in SS horses (P ¼ 0.037). Total glucose transfer during exercise tended to be greater in SS horses (0.027 6 0.002 mmol/min) compared with FF horses (0.023 6 0.002 mmol/min) (P ¼ 0.109). This study characterized the effect of diet on glucose kinetics in resting and exercising horses using new modeling methods. Horses adapted to a fat-supplemented feed utilized less glucose during low-intensity exercise. Fat supplementation in horses may therefore promote greater flexibility in the selection of substrate to meet energy demands for optimal health and performance.

A Quantitative Analysis of the Effects of Feeding and Daily Variation on Plasma Acid-Base Status in Resting Horses

A Thesis Presented to The Faculty of Graduate Studies of The University of Guelph by
KERRI JO SMITHURST, 2003

Conclusions:

Daily variation in the measured blood constituents identified in this study was due to either feeding or dehydration. All values were within physiological limits, showing that any circadian rhythm evident in this study was within clinical reference ranges, with the exception of [TCO2]. Ninety percent of the horses had a [TCO2] above 35.0 mmol/L at some point during the study and 70% of the horses had a [TCO2] above 36.0 mmol/L and may have received a positive TCO2 test result in the Ontario racing industry.

Although no change in electrolytes over the 25-h DVT was found as compared to initial concentrations there was a tendency for the electrolytes to have a nocturnal variation, with decreased [Na+] and increased [Cl-] as shown by the change in [SID]. The only change in electrolytes when compared to initial concentrations was an increase in [Cl-] following the morning feeding. The small change in [Cl-] post-feed and the potentially small changes in [Na+] and [K+] found in this study negate the requirement of time dependent reference ranges for electrolytes for blood testing.

There was also increased [glucose] and [PP] as well as decreased PCO2 and pH found following the morning feed. The same variations were not present following the evening meal. The discrepancy between morning and evening feeding responses could not be determined to be due to a daily variation as it is possible that the continued digestion of hay over the day attenuated the evening response to feeding.

Theoretically, the independent variables account for all of the changes in [H+] and [HCO3-] (and thus [TCO2]) using the physicochemical approach to acid-base balance. In this study, however, contributions of the independent variables ([SID], [Atot] and PCO2) were not able to fully account for changes in either [H+] or [TCO2] as calculated by the physicochemical equation.

You can download the entire thesis here.

LITERATURE REVIEW by Kerri-Jo Smithurst, University of Guelph

A Summary of the Effects of Feeding and Daily Variation on Acid-Base Status in Resting Horses

Plasma acid-base state affects, and may also be a reflection of, the health of equine athletes. The physicochemical model, as developed by Stewart (1981), defines the blood constituents that effect or determine acid-base state. These constituents, the partial pressure of carbon dioxide (PCO2), the strong ion difference ([SID]), and the total concentration of weak acids and bases ([Atot]), are the independent variables in the physicochemical equation. These independent variables are affected by external and internal influences throughout the day. The acid-base state in equine plasma can be completely described by the equilibrium between the independent variables and quantified using the physicochemical approach to acid-base balance.

By monitoring plasma acid-base parameters the occurrence and origins of daily variations can be understood. Variations in plasma result from diurnal influences such as activity and feeding, nocturnal influences such as sleeping, and the underlying circadian rhythm of an organism. Results from blood analysis affect the interpretation of a horse’s biochemistry, which leads to conclusions about health and affect drug-testing results.

The purposes of this literature review are to provide an introduction to acid-base assessment in clinically normal horses at rest and outline changes observed with feeding over a 24-h period. The literature on diet, feeding and daily variation of blood acid-base status of horses at rest is summarized. The purpose of the research described in this thesis is to investigate effects of feeding and daily variation of equine blood parameters on plasma acid-base status. Therefore, the presented physiological information should improve our basic knowledge of the daily changes in plasma acid-base status and set the stage for further research on acid-base status in horses.

download the review article or the entire thesis (includes references)

EXCERPT:

Usually a combination diet of forage and grain rations is fed to performance horses. However, when and how much the animal is fed is also an issue; it can vary from complete access to pasture forage with a small amount of grain supplement to two feedings a day with a high grain to forage ratio. The effect of diet depends both on the type of feed itself and the timing of feeding of horses; individual large meals have an immediate impact over periods of 6-8 h via fluid shifts, while metabolic/respiratory effects appear to be the main influence over 24 h (Kronfeld 2001, Mongin 1981).

CONCLUSION, RELEVANCE AND HYPOTHESIS

The acid-base state can be described by the equilibrium between the independent variables, [SID], [Atot], and PCO2, and quantified using the physicochemical approach to acid-base balance. Acid-base status is affected by daily variations due to feeding factors (including DCAD, amount, composition and timing of meals), confounding the ability to establish baseline values for plasma constituents. The influence of feeding and exercise as well as incomplete sampling over a full 24-h period have confounded research looking at daily variations in equine plasma constituents.

Besides the importance of establishing baseline values for plasma constituents, acid-base variables are important to the horse racing industry for drug testing. Alkalizing agents are used to enhance performance. Drugs can be used to manipulate plasma [TCO2]. A TCO2 blood test is performed in Ontario prior to both Standardbred and Thoroughbred races to determine whether an alkalizing substance (usually in bicarbonate form) has been administered (colloquially known as “milkshaking”). A [TCO2] greater than or equal to 37.0 mmol/L in venous blood plasma is considered a positive test. [TCO2] is a measure of the total carbon dioxide concentration in blood, which is primarily made up of HCO3- and CO2 in solution. However, CO2 occurs naturally in the blood, therefore controversy exists over the reliability of the TCO2 test. TCO2 status is also affected by Hct, Hb, total [PP], Na+, K+, Cl-, Ca2+, Lac- and Pi concentrations. By quantifying the plasma acid-base variables under minimal outside influences the daily variation of [TCO2] can be assessed.

We hypothesized that equine plasma acid-base parameters exhibit daily variation independent of feeding and exercise. We examined variation in plasma [TCO2] and other plasma constituents throughout the day, without the effects of feeding, to identify the main factors in blood that determine the daily acid-base state of the horse. The purpose of the first trial was to identify the main electrolyte and acid-base constituents in blood plasma that exhibit daily variation. The second trials purpose was to determine the effect of feeding on plasma TCO2 and 19 blood constituents describing the acid-base and electrolyte state of horses. Blood constituents were assessed to allow definitive determination of factors affecting [TCO2] and other acid-base variables.

Kerri-Jo Smithurst, Department of Human Biology, University of Guelph, September 2002

Abstract:
Track racing relies heavily on the horse’s anaerobic metabolism to produce the speeds necessary to win. One widely accepted theory is that a major limiting factor to high intensity exercise is the production of lactic acid in the muscles. This paper examines the way lactate is produced and utilised in the horse. It outlines how lactate affects the horse during exercise and describes metabolic changes occurring with high intensity exercise.

Download the entire article

Summary:
Traditionally it was thought that the accumulation of Lac- during high intensity exercise was a result of an oxygen limitation within the muscle cell. The term ‘anaerobic’ or ‘lactate’ threshold was given to indicate the point where exercise intensity reaches an abrupt increase in [Lac-]p (Wasserman et al. 1986). However, lactate is also created and utilized under fully aerobic conditions (Brooks 2001) and there seems to be more of a moderate rise in plasma lactate levels (Myers and Ashley 1997). The formation of lactate depends on several factors, only one of them being oxygen availability (Brooks 2001).

Lactate is a metabolic intermediate that can be oxidized or utilized as energy. The mandatory coupling of Lac- and H+ increases intramuscular acidification that may have many effects resulting in the limitation of high intensity exercise. During experiments where the acid-base variables were manipulated during exercise inconsistencies appeared in these relationships (Jones et al.1977). Problems also appeared in animal experiments where [Lac-] changes were not related to changes in [H+] (Jones and Heigenhauser 1992). Subsequent studies indicated that a variety of conditions were contributing to increased [H+] with exercise (Stainsby and Eitzman 1988, Heigenhauser et al.1990).

Using a multifactorial theory to explain force reduction during high intensity has [H+] affecting Lac- directly through the inhibition of key glycolytic enzymes as well as indirectly through inhibiting the contractile process (Bonen 2001). Heigenhauser and colleagues (1990) estimated the relative contributions of the different factors from studies with exercising humans. They found that increases up to 30% may be due to increases in PCO2, 40% or more may be due to reductions in [SID] and 30% due to changes in [Atot] and KA (Jones and Heigenhauser 1992).

A major problem with the Henderson-Hasselbalch approach is that in principle it is much more descriptive than mechanistic (Jones 1987, Stewart 1981) and the greatest advantage of the physicochemical approach over the traditional is in its quantitative assessment (Constable 1999). A limitation with the traditional approach is that the equation can only be accurately applied to ruminant plasma at approximately normal T, pH, protein concentration, and sodium concentration (Constable 1999). The physicochemical approach permits a better evaluation of a greater range of acid-base disorders as well as allowing greater understanding of acid-base physiology (Aguilera-Tejero 2000). It also brings us past the conventional descriptions of acid-base in terms of the CO2 system as the descriptions of base excess and deficit are limited do not work intramuscularly (Johnson et al. 1996). By acknowledging the numerous variables involved in acid-base balance, bicarbonate becomes only one of the many factors influencing lactate concentration (Johnson et al. 1996).

The existence of the Lac-/H+ cotransporter reduces the increasing [Lac-] during activity in the active muscles and facilitates its uptake in other fibres (Juel 2001). From their study Tonouchi and co-workers (2002) found that the contraction-induced increases in Lac- transport, occurring at high [Lac-], may be attributed to changes in the intrinsic activity of MCT transporters. The internal pH is regulated by the H+/Na+ exchanger, which serves as a safety system against any major changes (Juel 2001). It seems that the transport systems not involving Lac- regulate pH at rest, and contribute to its fine adjustment, and that the MCTs are the main transporter for the large Lac- productions with intense exercise (Juel 2001).