Like Baby Boomers, the number of older horses is increasing by leaps and bounds. Better health care is carrying more into the senior-citizen category, and that’s generating a new batch of health and wellness concerns. One of the most frequent complaints from owners of older horses is muscle loss, which has several possible causes.
Weight Loss in General
We don’t expect our seniors to be bulging with muscle, but when bulk starts to obviously shrink it’s time to investigate why. The first thing to be ruled out is excessive weight loss in general. There’s a layer of fat between the skin and muscles throughout the body that is particularly generous over the top line and rump, which are the areas most owners notice first.
To differentiate between fat and muscle loss, step back and take a close look at the horse’s body overall. If the ribs are well-covered but muscling looks poor, you have a muscle-loss problem. If the horse seems skinny overall, it’s likely inadequate calorie intake or utilization. Get a vet check and consider changing his diet to one that is easier to chew and digest.
Aging alone typically causes a somewhat ”normal” loss of muscle bulk. However, regular exercise can minimize, and possibly reverse, age-related loss of muscle mass. Consistent work at a level that is comfortable for the horse will benefit the muscles, and also the joints, heart, lungs and mental outlook.
You can take him along on hacks, find 15 to 20 minutes to longe him, or figure out which turnout buddies will keep him moving the most (e.g., a devilish young pony is a safe companion, inexpensive to keep and usually effective). Use it or lose it definitely applies to older animals.
If your senior was retired because of a disability like arthritis or a lung problem, don’t assume this means all formal exercise is out. There will be limitations, but complete inactivity often leads to further decline. If you’re unsure, ask your vet about that individual horse.
The combined effects of inefficient chewing and possible reduced digestive efficiency mean that more attention should be paid to the protein intake of older horses, especially if you’re having problems maintaining muscle. Intake of crude protein for older horses should usually receive a minimum of 700 to 750 grams of protein/day for a 1,100-pound horse, which is similar to the recommendations in the 2007 NRC for horses in the ”elevated requirements” category.
This could be obtained from 22 lbs. = 10 kg of a 7.5% crude protein grass hay or 11 lbs. = 5 kg of a 15% protein alfalfa hay. However, the digestibility of the protein also comes into play here and most older horses do better when at least part of their protein is coming from more easily digested sources such as grains, seeds, seed meals or whey.
Another issue is individual amino acids. Lysine is a pivotal amino acid in equine diets. Without adequate lysine, overall protein requirements are higher. Feeding additional lysine even when the diet meets NRC recommendations can improve muscle mass.
Threonine and methionine are the next most important, then the branched chain amino acids, especially leucine. Feeding a diet with a variety of hays and concentrate types provides different amino-acid profiles and helps avoid deficiencies, but supplementing key amino acids can also be very helpful with older horses.
Disease should be ruled out, especially in horses that drop condition quickly. Cushing’s is among the most common and causes a hormonal myopathy and muscle loss. Secondary muscle loss is common with cancerous conditions and heart failure, kidney or liver disease. Natural immunity to parasites often wanes in older horses so don’t overlook this possibility either.
Be sure the horse’s calorie and protein intakes are adequate, and the horse is otherwise healthy. Add a regular exercise program appropriate for the horse’s limitations.
Check to be sure core antioxidants of omega-3s (feed flaxseed to your older horse for this), vitamin E, selenium, copper and zinc are being consumed in adequate amounts.
Consider a low-level vitamin C supplement, which is of great benefit to older horses.
With supplements, B vitamins are important for the proper utilization of energy sources and protein metabolism. It’s assumed that horses meet their B vitamins needs from food and the synthesis of B vitamins in the intestinal tract. However, populations of micro-organisms in older horses aren’t always great. Support of intestinal micro-organisms and/or B vitamin supplementation is reasonable.
If these basics don’t work, add additional lysine to the diet. Include leucine/BCAAs if the horse is being worked at more than a light work load.
ALA and ALC are usually supplemented together in other species, but if you have the above supplements in place we’d try ALC alone first (see sidebar).