It’s no secret that I have spent my career emphasizing the importance of nutrition. My office has a bottle of penicillin and Banamine for emergency only instead of a wall of medicines. I’ve even been called a tree hugger, which doesn’t make a lot of sense but I suppose means on the fringe. However, I do not consider nutrition to be a form of alternative therapy.
My minimalist pharmacy is not because I have a problem with using drugs. It’s just that we don’t often need them. Drugs have an important place in horse care. Some, like antibiotics, vaccines and deworming medications, have made a huge contribution both to longevity and quality of life.
That said, good health is about more than drugs.
Nutrition is the most misunderstood and under utilized tool for creating, maintaining and restoring vibrant health. There is much more to it than just providing enough calories to hold a good weight. There is no substitute for correct nutrition. It can accomplish things that no drugs can do. There are also disorders that can only be treated with the correct nutrition.
Nutrition is not an alternative therapy. It’s an indispensable part of optimal health. It’s not on the fringes of health care – or at least shouldn’t be. Nutrition is a science and worthy of respect.
The function of the immune system is to protect the body from outside organisms and substances that may harm it. It should be no surprise then that mucus membranes lining all the portals of the body open to the world have high immune capacity. The most important of these is the digestive system.
The immune system of the intestinal tract is called GALT – gut associated lymphoid tissue. Throughout the intestinal tract there are immune system cells, macrophages and lymphocytes, under the intestinal lining cells. Structures called Peyer’s patches are very similar to lymph nodes and are located in the small intestine. They have been called the tonsils of the intestinal tract. Specialized immune cells also line the liver.
Microscopic view of Peyer’s Patches lying under the lining cells of the small intestine
Microfold cells, or M cells, are located over collections of lymphoid tissue along the intestinal tract. The M cells reach out to engulf bacteria and other material from the intestinal tract then pull it inside and present it to immune system cells. This material is processed through T and B lymphocytes, eventually resulting in the production of IgA antibodies, which remain in the local tissues to protect them. However, it doesn’t stop there.
The lymphocytes that will eventually produce local IgA antibody are released into the bloodstream before they come back to home in the intestinal lining again. In the process, they can share this information with the entire body’s immune system so that the rest of the body can produce circulating antibodies (IgG, IgM) to the same organisms the local IgA targets. A good example of how GALT interacts with the rest of the body is oral vaccines. Several human oral vaccines have been developed, including against polio and malaria. Oral rabies vaccines in bait have been used to successfully battle rabies in wild animals.
Research has found that interactions between the immune system and the bacteria colonizing it can have profound effects. Probiotics are defined as bacterial strains capable of colonizing and surviving in the gut which have a beneficial effect on their host by suppressing the growth of harmful bacteria and interacting with the immune system.
Documented effects of probiotics to date include directing activity of immune cells, encouraging production of protective mucus, reducing inflammation and increasing the production of IgA antibody, which in turn decreases the risk of allergy related IgE antibody forming.
Prebiotics support the growth of probiotic strains of bacteria by feeding them or maintaining an environment in the gut that is favorable for proliferation of probiotic strains. Some also have direct immune system effects.
The diet itself plays a major role in the health of the intestinal tract and the beneficial probiotic strains inhabiting it. Quality hay free of mold and other easily fermentable dietary ingredients like beet pulp feed these beneficial strains. Special complex carbohydrates from yeast cell wall or plant arabinogalactan are potent immune stimulators. Avoid overfeeding of grains as this can bypass small intestinal digestion to upset the balance of organisms in the hind gut.
In summary, the intestinal tract is a major player in the immune system. It has been estimated that 70% of the body’s immune system cells originate there. Immune activity in the gut has a body-wide effect. One of the best ways to boost and balance the immune system is through the oral administration of probiotics, prebiotics and other substances documented to support and balance immune function.
There is no question climate change is here and we and our animals are being subjected to steadily increasing extremes of heat. Managing this is challenging.
The first question is, and should be, can I work my horse in the heat. A heat index chart can be found here https://tinyurl.com/2p9xn93y . Caution should be used above a heat index of 80. From 90 to 102, overheating occurs easily. Above that level, I do not recommend exercising the horse. During a heat wave you are most likely to find a window of opportunity around dawn or even at night.
Even horses not being actively worked are at risk of dehydration with consequences like impaction colic. Young foals , overweight horses and very old horses, especially those with Cushing’s/PPID, are at highest risk for overheating.
Dehydration begins with salt depletion. The body requires salt to hold water in the tissues and the brain reads salt concentrations to tell it when to start water conservation through reduced urine output, and when to trigger thirst. Salt depletion is a consequence of both inadequate intake and losses in sweat.
Adult-size horses should get at least 2 ounces (4 tablspoons) of salt in hot weather, more if they are visibly sweating – e.g. along the chest, under the mane, between the hind legs. Add another half ounce for lactating mares. Adjust down for smaller animals.
For horses being worked in the heat, feed one dose of a balanced electrolyte, https://www.uckele.com/pro-lyte-pellet.html for each hour of heavier sweating (count sweating during cool downs). Important: This is in addition to the 2+ oz of salt fed at baseline.
Do not rely on consumption from a block to meet needs. Horses’ bodies often become salt depleted quickly then “reset” to maintain blood sodium levels at the expense of the tissues. When this happens, the brain thinks everything is normal but the horse is actually dehydrated.
If the horse won’t eat the required amount mixed into feed, you can sprinkle it onto moistened hay. A quick dunk or spray will do. You can also offer salted water, up to 8 tsp/gallon, but only if the horse also has an unlimited supply of fresh water.
Speaking of fresh water, a problem with automatic waterers can be disastrous at this time, especially if you do not have meters on your waterers. Contact the manufacturer for advice on maintenance. This article from a manufacturer gives some ideas on what is involved in maintenance https://www.horsedrinker.com/how-to-inspect-your-automatic-waterer/ . Be particularly careful with new horses not accustomed to using them.
The skin pinch is the most popular test but is unreliable in older horses, horses with DSLD and under very dry environmental conditions.
It is a myth that you shouldn’t hose a hot horse with cold water. In fact, the colder the better. After the water running off the horse has cooled, scrape off excess to allow for easier evaporative loss at skin level, where it counts.
There should always be shade available and fans if possible. Misting fans are best.
It’s a lot to think about but your horse’s health, even life, depend on proper care in the heat.
Earlier studies, including by the late Doug Leach, PhD, failed to show any difference in strength between white and black hooves when blocks of tissue were subjected to compression.
While some myths are just plain not true, in this case the truth may lie between the two claims. The difference between white and black hooves is presence of the pigment melanin. This would not influence the structure of the hoof horn or its ability to withstand compression but it could have other effects.
The outer hoof wall, which is the only layer that shows pigment, is a specialized version of the outer layers of skin. It is composed of dead cells with fats holding them together and preventing moisture loss from the lower levels of live cells. Sun exposure without melanin protection leads to excessive drying which could in turn result in cracks and trouble holding nails.
Interest in keeping donkeys as horse companions is growing. While it’s probably true that both species would prefer the company of their own kind, the fact is they do get along very well once the horse gets over the initial “What the heck is that??” reaction.
As both are equines, routine care like vaccinations, dewormings and hoof trimming are identical. However, there are some nutritional considerations that can get you in trouble, and an awful lot of misinformation or bad advice on the internet.
Optimally nourished donkeys do not look like the pot-bellied somewhat scruffy creatures you too often see. It’s easy to keep your donkey looking as slick and attractive as your horse once you understand how.
Feeding a donkey like a horse can result in obesity and laminitis. On an average, the donkey requires only about 75% as many calories as a horse or pony of the same weight. This is due to a combination of much more efficient fermentation of fibrous feed components and possibly a somewhat lower metabolic rate. Unfortunately, this has led to some pretty drastic recommendations on feeding such as feeding nothing but straw. Donkeys can also survive on protein restrictions too low for a horse but survive is not the same thing as thrive. It’s likewise true that donkeys can survive several days without water (ancestors were desert dwellers) but again do you think that means you should withhold water? The goal of nutrition should be to optimize, not push the limits.
Donkeys on pasture of sufficient quality to maintain weight on a horse should be muzzled. If the donkey gets too thin (not very likely!), you can leave it off for an hour or so and adjust as needed. If on hay, a 100 kg donkey will need about 3 Mcal/day or 1.7 to 2 kg of a moderate quality grass hay. If you are feeding a nice but mature cut of hay, you will only be able to feed about 10 to 15% more weight by going to all straw instead but will lose out significantly on protein and minerals.
Speaking of protein and minerals, there are no formal studies on protein requirements of donkeys, but lots of guesstimates on how little you can get away with. Reference is often made to urea cycling in donkeys, urea being the metabolized nitrogen remnant of protein. Donkeys are efficient at excreting urea back into their digestive tract. However, this only benefits the microorganisms in the gut, not the donkey directly because amino acids synthesized by the microorganisms are not absorbed in the hind gut. The only long term study available showed good weight maintenance on 1.2 grams of crude protein/kg of body weight daily. This is almost identical to a horse.
There is zero formal information available on mineral requirements of donkeys. Speculation is a poor substitute for fact so until differences are identified I advise applying horse/pony protein and mineral requirements to donkeys.
When you need a carrier for supplements, you can’t beat beet pulp. It soaks up as much as 4X its dry weight in water to result in a very low calorie carrier.
Enjoy your ‘long ears’ horse companion, and if you feed him right you can look forward to competition about which one of them is better looking.
Deworming by fecal egg count (FEC) is advocated as a way to avoid overexposure of parasites to deworming drugs. It’s important to understand the effect of deworming by FEC is primarily to minimize environmental contamination, not optimally protect the individual.
Young horses, PPID horses and seniors in general are at high risk for parasitism. Even some young adult horses have poor parasite resistance. Much damage is done by immature forms that are not even laying eggs yet.
The problem with FECs is their limited capacity to detect parasites.
– they only reflect adults that are actively laying eggs at the time of the test – egg-laying activity may vary seasonally – tapes often missed because eggs are laid in packets/segments, not evenly mixed in the manure – can’t detect tissue forms or immature stages in the lumen but these can be the most harmful for the host – bots missed – pinworms missed (lay their eggs on the perianal skin) – Strongyloides in adults not detected
None of that matters in terms of herd health because small Strongyles are the major threat and the only mode of transmission is contamination of the environment by fecal shedding, but it sure matters to the individual.
The other problem is technical limitations. Samples sent through the mail are useless. Samples not collected as soon as they are passed then kept cold are likely inaccurate. The reason is that eggs hatch and flotation methods do not pick up larvae.
As for resistance, helminths come equipped with drug metabolizing enzymes which in some individuals transform the dewormers to harmless compounds. Obviously those genetically fortunate enough to possess those enzymes are the most likely to become resistant by upregulating enzyme activity when they are exposed to the drug – if it doesn’t kill them first.
Any parasitologist will tell you the major way resistance develops is underdosing. (Ditto for antibiotics and bacteria.) What doesn’t kill them makes them stronger. Frequent exposure can cause a dewormer to go from a 20% failure rate to 80% or higher.
It’s also true they can’t be fully resistant to a drug they have never been exposed to so there is an argument in favor of not automatically exposing parasites to a variety of dewormer drugs (rotation). On the other hand dead parasites do not develop resistance or pass it on to their descendants.
In any case, it’s wise not to attempt to deworm with drugs that are known to have widespread resistance in the species you are treating. This includes the following reported resistances:
These are the large Strongyles which do significant damage to the intestine and arterial system when they are migrating. Back when I was starting out as a veterinarian we still had to deal with many horses with S. vulgaris damage and it wasn’t pretty – severe recurrent colic, intestinal infarction, peritonitis, debilitating lameness, even to the point of euthanasia. If you wait to see the eggs in feces, it may be too late. Regular deworming with ivermectin or moxidectin had all but wiped them out.
Deworming strategies have gone from one extreme to another – from frequent, regularly scheduled treatments to deworming only on evidence of egg-laying adults on FECs. Neither is ideal. Speak to your vet about developing a program that is optimal for your individual horse.
If you follow news releases and articles about equine laminitis you have surely seen mention of MMP enzymes since the late 1990s.
Turns out they are not the major players as was originally thought.
MMPs are matrix metalloproteinases – enzymes that break down connective tissue protein/collagen in the body.
The basement membrane in the hoof is a thin layer of connective tissue lining the junction between the dead laminae of the hoof wall and the live laminae of the inner hoof. This system locks the hoof wall to the tissues inside like Velcro.
In laminitis caused by things like colic/gut infections, black walnut shavings, grain or experimental fructan overload, it was noted the basement membane is damaged or destroyed and that the level of MMP enzymes is increased. This led to the theory that the activation of MMP is what causes laminitis.
These various causes of laminitis are also associated with inflammation. White blood cells invade the hoof and the body in general is in an inflammatory state. It didn’t take long for research to start showing inflammation was not a feature of endocrinopathic laminitis (caused by high insulin).
Basement membrane damage and high MMP levels are also not a feature of endocrinopathic laminitis. In fact, it has also been shown that most of the MMP present in fructan induced laminitis is inactive, bringing into question what, if any, role it plays (Visser and Pollitt 2012).
Since it is estimated that 90% of all laminitis cases are caused by high insulin, these findings have important indications. They explain why anti-inflammatories like phenylbutazone or firocoxib have limited effect in laminitis pain. They also mean you need to involve your veterinarian in a diagnostic plan that determines what type of hormonal disorder your horse has and how to most effectively get insulin down because that is the only thing that will relieve the pain. Ancillary supplements to balance the diet and improve blood flow to the hoof also play an important role.
It is a widely held opinion that horses “need” grain.
Horses have been fed grain from at least the time of the Roman Empire, probably for as long as people have eaten grains.
Grain is a more concentrated source of calories than hay or pasture. It is much, much higher in starch than hay or pasture. That starch can be digested in the horse’s small intestine but there is a limit to how much they can handle.
In a horse that is not accustomed to eating grain, as little as 1 g of starch/kg of body weight, the equivalent of 2.75 pounds of plain oats for an 1100 lb horse, will result in spill over into the large intestine.
Horses can adapt to eating high starch foods over time. In adapted horses, the recommended safe upper limit would be 5.5 lbs plain oats per meal for an 1100 lb horse.
Those changes could be prevented by feeding the horse a timed release intestinal buffer. Since the evidence of inflammation (inflammatory cytokine level) occurred only one hour after feeding, it must have originated in the stomach and/or small intestine from fermenting organisms in those areas causing pH to drop.
As undesirable as inflammation and bacterial products in the blood sounds, these events reverse themselves. Obviously horses are not getting ill from this. However, until more is known about the significance or long term consequences you should think twice about heavy grain feeding.
Grain is completely out of the question for horses with metabolic syndrome. It should be minimized or eliminated for growing horses because of the connection with developmental orthopedic disease. Inactive and pleasure horses can also do quite well with no grain and will maintain a much healthier weight – ideally a body condition score no higher than 5 https://www.canr.msu.edu/news/body_condition_scoring_in_horses .
What about vitamins and minerals? Commercial feed companies have done a good job of convincing people that horses need a bagged grain. Truth is, they don’t. No hay or pasture is perfectly balanced and nutritious but grains, and even balancers, often magnify common issues like high iron and manganese without correcting them.
You are better off investing that feed bill money in a forage analysis of your hay or pasture, then have your diet balanced. I do this for free for Uckele customers. Just send me an e-mail at kellon “at” uckele.com.
Like all herbivores, the horse has evolved to get most of his calories from fermentation of fiber. Humans can’t do that. The digestive tracts of the two species are too different.
Ketones are not a super fuel. They are a waste product of fat metabolism when more fat has been mobilized than the body can burn. No body cell or tissue type prefers ketones over glucose. Glucose is essential for life.
There is a saying that “fat burns on the flames of carbohydrate”. This is because fats can only be burned aerobically in the mitochondria. They have to enter the Krebs cycle. A key intermediate in that cycle is called oxaloacetate and that must come from pyruvate. Pyruvate only comes from glucose or breakdown of some amino acids.
[Those interested in the details of the biochemistry should see this short video https://www.youtube.com/watch?v=WlUPaImRZts . Note that the pyruvate they show entering the cycle as acetyl-CoA is from glucose. Fats are also metabolized to acetyl-CoA so also must combine with oxaloacetate.]
Horses with metabolic syndrome are genetically programmed to be that way. Whether it becomes a problem or not depends on diet and exercise. They can go all day on hay alone and don’t require any grain. They certainly don’t need more fat or ketones.
Although most people can quote the percent protein in their feed, and manufacturers make a point of it, this particular piece of information is almost worthless. The horse’s protein requirement is in grams per day, not a percentage in the grain. The percentage itself – e.g. 10% protein = 10 grams protein per 100 grams of feed – tells you nothing without knowing how much of it the horse eats. You also need to know what the horse’s requirement is and how much protein is coming from the rest of the diet.
Let’s take a 500 kg (1100 pound) horse in moderate work to see how this works. According to the NRC recommendations, that horse needs 1.536 grams of protein per kg of body weight so 768 grams/day. If the horse is eating nothing but a 9% protein hay, 10 kg (22 lbs) a day, his protein intake is 900 grams. If that same horse is eating 2.5 kg (5.5 lbs) of a 10% protein grain and 5 kg (11 lbs) of hay his protein intake is only 700 grams/day, close but deficient. There is also new research showing that the ideal protein intake for working horses is 2+ grams/kg of body weight, making the diet considerably more deficient.
If you upgrade the horse above to a 10% protein hay, intake would be 1000 grams on the hay only diet and his needs would be met. What about if you change the grain to 14% protein, same amounts fed of grain and hay? The 5 kg of hay would provide 500 grams of protein and the 14% protein grain at 2.5 kg (5.5. lbs) gives 350 for a total of 850 grams versus the 1000 needed.
Let that sink in. If you feed nothing but a 10% protein hay you can meet even the higher end of estimated protein needs for a horse in moderate work. If you cut hay in half and substitute 5.5 lbs of a 14% protein grain, you will be deficient.
The take home message here is that the % protein in your grain is no guarantee the diet is adequate, even if a “high” protein like 14%. That 14% protein grain has 1.4 times more protein than a 10% protein hay, but 2.5 or even 3.0 times more calories. When you feed grain, if you don’t want weight gain you have to cut back on the amount of hay fed. In many cases that is actually the reason for feeding grain – to control the amount of hay needed. If you feed 1 lb of grain instead of 3 lbs of hay to equal calories, that grain must also have 3 times more protein than the hay to keep protein intake the same.
The only way to know if your diet is adequate is to know the requirement and the protein level in everything fed. For adult horses at maintenance or low work, it’s actually not often an issue if hay quality is good. For more active horses, pregnant, breeding, lactating and growing horses, it’s an entirely different story because their protein needs are much higher. Don’t assume a “high” protein grain can get the job done.