The Horse

FEB 2019

The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.

Issue link:

Contents of this Issue


Page 36 of 51 | The Horse February 2019 37 often prescribed by a veterinarian, there's generally no real diagnosis of what's plaguing the horse. Further, because the owner "self- prescribes" a joint supple- ment to treat a lame horse, he added, the vet only sees the horse when his sound- ness or comfort decreases dramatically. McIlwraith said many joint supple- ments contain glucosamine and/or chondroitin sulfate. Other common ingre- dients marketed to promote joint health include manganese, vitamin C, hyaluron- ic acid, omega-3 polyunsaturated fatty acids, rare earth minerals, avocado and soybean unsaponifiables, green-lipped mussel, cetyl myristoleate, methylsulfo- nylmethane, and various herbs. McIlwraith said some products have undergone in vitro (in the lab) testing. The problem, he noted, is it's unclear what happens to the supplement and its efficacy after it passes through the horse's GI tract. As such, some research- ers are working to develop "predigestion" techniques to allow them to study the products in an environment more closely resembling that of a horse's gut. Recently, he said, in vivo studies have demonstrated value for a few OJS, includ- ing avocado soy, oral hyaluronic acid, and a mixed product called "Sasha's Blend." Additionally, combination supplements, such as those marketed to support both joints and gut, have become popular. However, McIlwraith said, it's not clear how different ingredients work together, so claims for synergism are unproven. On OJS efficacy, "manufacturers of these products are investing in research, but most (studies) do not meet a quality standard that provided sufficient con- fidence in the results," he said. "Conse- quently, the overall level of evidence for in vivo demonstration of efficacy is weak." The Future McIlwraith sees biologic therapies as the future of treatments in all species. One of these is autologous conditioned serum (ACS), also known as IRAP (interleukin-1 receptor antagonist protein). When a joint sustains injury, trauma stimulates release of inflamma- tory proteins, including IL-1 and other cy- tokines (which signal cells to move toward inflammation). Researchers have shown that ACS/IRAP can block IL-1 activity on joint tissues and slow OA progression. Vets have used platelet-rich products, but we have no definitive data and little ex- perience with effectiveness in OA, he said. McIlwraith and his team have shown evidence for the value of bone-marrow- derived mesenchymal stem cells in treat- ing both OA and soft tissue injuries. He cautioned that while stem cells have been shown to help heal a variety of injuries, not all products are created equal. Finally, he said, gene therapy—using genes to treat or prevent disease, includ- ing OA—has proven effective in helping horses, but hasn't made it to market. 5 Things to Consider When Feeding Horses According to Research What should I feed my horse? Equine nutritionists look both to research and their own experience to answer this ques- tion. Besides considering stage of life and activity level, they must weigh variables such as environment, climate, genetics, and health conditions, which can alter the horse's needs and lead to, perhaps, the most appropriate answer: "It depends." The conference ended with a round- table on putting feeding requirements— particularly those in the National Research Council's (NRC) Nutrient Requirements of Horses Sixth Revised Edition 2007—into practice. Harris; Peter Huntington, BVSc, MANZCVSc, director of nutrition at KER's Australasian facility, in Victoria, Austra- lia; and Laurie Lawrence, PhD, professor of equine nutrition at the University of Kentucky, in Lexington, fielded questions posed by moderator Pagan. Here are five take-home messages for horse owners from this session. 1. Stop and consider whether you're overfeeding your horse or pony. "(Horse owners) generally do believe that their horse/pony is doing more work than they actually are," said Harris. "They can be putting in the inappropriate (work level into the NRC's tool to calculate diet) and throwing it all off." This extends to performance horses, too. "There's a bit of a disconnect between how hard people are actually training or not training their horses," said Pagan. Lawrence said the NRC adapted its tool from three categories—light, moderate, or intense—to four, adding very heavy work, "to better separate out the horses that were truly in light exercise from those that were moderately working, with the idea that the very heavy work category would be the horses that were racing, elite three- day (event) horses, elite polo horses." Even if they're classified correctly, it's important to remember that some horses seem to be able to maintain condition on fewer calories than others. And, Harris added, researchers have confirmed cer- tain animals can be weight-loss-resistant. On the other hand, you'll see horses that struggle to keep weight on, even if they aren't in work. "Horses are individu- als just like us, and there are some ani- mals that seem to need more energy than you would think just to maintain their condition, although, if this persists or gets worse, it is always worth getting your veterinarian to check there is no underly- ing clinical problem," said Harris. 2. Take it slow and steady when reintro- ducing feed to the severely underweight horse. Feeding the very emaciated horse too many calories too quickly can lead to refeeding syndrome, in which the horse can suffer heart and respiratory problems, as well as muscle damage, in part due to abrupt electrolyte imbalances. Veterinary advice is, therefore, always needed in these cases. However, even for the thin rather than the chronically starved ani- mal, changes in the diet quantity and/or quality need to be made gradually. A slow approach can make it seem like it takes ages to see horses gain weight, said Harris, but once they start to, often the increase can be surprisingly rapid. "If there's no clinical reason (sickness/ abnormality) why they've lost weight, they often will put on more weight than required when fed for weight gain— hence, the continued need to monitor and adjust your feeding program," she said. "Interestingly, weight loss studies in obese animals have shown that whilst more severe restriction might increase the rate Horses are individu- als just like us, and there are some animals that seem to need more energy than you would think just to maintain their condition." DR. PAT HARRIS

Articles in this issue

Links on this page

Archives of this issue

view archives of The Horse - FEB 2019