Question
Sky is my 13-year-old Morgan gelding; he stands 14.3 hands and weighs 780 lb (355 kg). He is moderately thin now with visible ribs and a loss of topline. He spends 22 hours each day in his stall and a couple hours with me engaged in grooming, hand walking, and some low-level exercise (longeing, driving, etc.). He has soaked hay (13% NSC) available to him all day. In addition to the hay, he receives a ration balancer, salt, flaxseed, and supplements for joint and gastric health. Sky once weighed about 840 lb (382 kg); with a diagnosis of PPID, he had to go on a diet to lose excessive fat and that included being removed completely from his pasture. Reducing caloric intake and adding pergolide about a year ago has resulted in weight reduction but also a loss of topline and muscle atrophy. How can I help restore him to a healthy condition without excessive fat?
Answer
Transitioning to a hay-only diet from pasture can present some nutritional challenges. Horses generally do not consume as much hay as fresh forage, and the nutritional value of the hay is often lower than pasture, both of which contribute to weight loss. Adding a concentrated source of digestible calories with oil may help, as might the addition of more digestible fiber sources such as beet pulp and soy hulls.
The ration balancer is appropriate, but it is important to consider nutrient losses in hay caused by soaking, losses beyond just sugar. Soaking time is normally adjusted based on the sugar content of the hay. Ideally, feeding hay that has no more than 10-12% nonstructural carbohydrates (NSC) is recommended for horses with insulin resistance. If your hay has 13% NSC, a shorter soaking time may reduce the sugar enough and not affect other nutrients. On the flip side, longer soaking times may leach other nutrients. In these cases, feeding more than the manufacturer’s minimum recommended amount of the balancer pellet may be necessary to ensure no nutrients are marginal in the diet. Having an analysis of the hay after soaking would be ideal to balance the diet but is not always possible.
Longer soaking times can also affect the hygienic quality of the forage as it can encourage mold growth. If you can source a hay that is lower in sugar, then soaking is not necessary and this would be the ideal long-term situation.
Fiber quality is important as it determines the amount of nutrition available to the horse and supports digestive health and function. If the hay is mature, characterized by lots of stems and few leaves, supplementing with a highly digestible fiber such as beet pulp or using a processed hay cube or pellet is a great way to provide additional calories to increase weight and improve muscling. While near constant access to hay is great for digestive and mental health, some horses cannot consume sufficient hay to gain weight, usually because of hay quality. Mature hay can be low in protein and deficient in essential amino acids. Replacing some of the hay with highly digestible fibers such as beet pulp or soy hull can help improve overall body condition and muscle mass. Hay replacement products are available that are suitable for PPID horses and could be offered with soy oil and the ration balancer.
Regarding Sky’s loss of muscle tone, limited movement due to stall confinement can be a factor, especially considering his recent history of turnout. Slowly increasing work intensity and frequency will allow Sky to be fed more while simultaneously heading off more severe metabolic issues. Time in a drylot might also help with reconditioning muscles.
Horses without access to pasture grasses benefit from a natural-source vitamin E supplement. Nano-E should be used because of its superior bioavailability. Horses can become deficient or marginal in vitamin E over time when not allowed to graze, even when fed a properly fortified feed. Vitamin E plays an important role in muscle health and repair, so vitamin E supplementation is extremely important in cases of atrophy.
Kentucky Equine Research has conducted many studies on fatty acid supplementation and found that the source of omega-3 fatty acids plays a key role in the health benefits they deliver. Supplement with marine-derived omega-3 fatty acids, particularly EPA and DHA as found in EO-3, instead of plant-based sources like flax, as horses have greater anti-inflammatory effects with marine-derived sources.
