Question
Murphy, my 15-hand, 1,200-lb (545-kg) aged Morgan gelding, is obese and sound now but at risk of laminitis, according to my vet. Keeping him at a boarding facility makes it hard to gauge how much hay he was fed during the slow lead-up to his current state. In an attempt to curb calories, we reduced the amount of hay to 12 lb (5.5 kg) per day. I have been given mixed advice on whether to feed alfalfa or grass hay, so I give him half of one and half of another. He has been on this diet for three months, and we’ve noticed no change in his weight. The barn manager suggests I reduce the hay further, to only 6 lb (2.7 kg) a day split into two meals. Other things worth mentioning: Murphy has not had access to grass in years, and he is housed in a sand corral where he is able to move around a bit. Weather permitting, I am able to exercise him a few times a week, but the winter sometimes precludes additional exercise. With the temperatures starting to drop, I am very concerned about Murphy’s health. What is the best diet for him?
Answer
Activating weight loss in horses can be challenging. The owner usually becomes frustrated by the amount of time it takes for weight loss, the barn staff can become upset by the careful weighing of meals and, of course, the horse is aggravated by the restricted diet. Weight loss is usually possible, but it’s best to have a clear plan with achievable goals coupled with tremendous patience.
For a horse with a long history of obesity, it can take weeks to months to see a change in body condition. Owners looking for immediate changes will often be disappointed. Tracking the process by monitoring body condition score (through hands-on evaluation) and weight loss (with the same weight tape) is recommended.
Before discussing how much hay your gelding should consume, it is important to address what type of hay is being offered. Easy keepers do quite well on mature hay that might otherwise be considered low quality (yellowish-green in color but free of dust, mold, and other impurities). This type of hay is often ideal for horses that need to lose weight because it provides necessary fiber and chewing time without excessive calories. Green, leafy hay that was harvested before full maturity likely contains more calories and tends to be higher in nonstructural carbohydrates (NSC).
Alfalfa should not be a part of Murphy’s diet because it is usually too rich in calories. Alfalfa might have been recommended because the legume is generally low in NSC (average 11%). Hay with less than 12% NSC is suggested for overweight horses that are battling metabolic conditions.
Once you find appropriate hay, it will be important to have it analyzed by a reputable laboratory to determine the NSC and digestible energy. If an analysis is not possible, soaking hay can help to reduce excess sugar. However, one drawback to soaking hay is that it decreases the dry matter, so slightly more should be fed.
Now, how much hay is needed? I understand that 12 lb (5.5 kg) of alfalfa/grass hay did not result in weight loss. However, changing to different hay, as described above, should help. In general, horses should consume no less than 1.25% to 1.5% of their target body weight in forage daily. With these percentages in mind, given a target weight of 1,000 lb (450 kg), Murphy should receive 12.5-15 lb (5.7-6.8 kg) of hay per day.
Feeding only two meals a day can be problematic because the small amount of hay will be consumed fairly quickly, leaving Murphy with an empty stomach for many hours. Constant acid production in the stomach can lead to irritation of the gastric lining and eventual ulceration. Splitting hay into several small meals a day and using a slow feeder is an excellent approach to managing forage intake of easy keepers. If you suspect he has any digestive discomfort from the low intake, you should consider a research-proven digestive supplement that targets the stomach and the hindgut.
Aside from gastrointestinal problems, the potential side effects of restricting forage include chewing wood, consuming bedding, and investigating other accessible fiber sources such as tree bark, all of which can be problematic.
From your query, you seem to understand that exercise is a critical part of weight loss and management of metabolic disease. As with all exercise programs, Murphy’s conditioning should begin gradually and become increasingly more difficult. He should receive some form of structured exercise for at least 30 minutes each day, five or six days per week. Shoot for low- to medium-intensity exercise. Heart rate should be 130-170 bpm during exercise. Keep in mind, the level of exercise should be appropriate for his level of fitness and soundness. Consider moving Murphy to a facility with an indoor arena or all-weather footing so the exercise component of his management can be achieved. KER ClockIt is one way to easily monitor heart rate during exercise. For sound horses, the importance of exercise should never be discounted.
Forage alone will not provide sufficient levels of nutrients, including copper, zinc, or selenium. The use of a ration balancer feed will provide a concentrated source of protein, vitamins, and minerals with minimal calorie contribution. Another option for horses consuming adequate protein from the hay would be a high-quality micronutrient supplement.
