Feeding Horses for Weight Gain

Picture courtesy of Purina

BY Purina Animal Nutrition

A common question asked by horse owners is “how do I put weight on a thin horse?” There are several factors that can lead to a horse being underweight, including health conditions, age-related issues, or simply, inadequate calories in the horse’s diet.

When dealing with a thin horse, it’s important to first look at the horse’s health status. Is the horse suffering from parasites, disease, chronic pain, ulcers, or dental issues?  These are all issues to be addressed by a veterinarian, and making a vet appointment is the first step in helping a horse gain weight. If weight loss is caused by a health condition, then addressing the condition may be all that is necessary to help a horse regain the lost body condition.

The veterinarian may find that the horse’s teeth are no longer adequate to chew long-stemmed hay, even with proper dental care. As horses age, their teeth wear down to the point that they are unable to fully chew hay, and, also with age, digestion and absorption becomes less efficient. In these situations, a highly digestible complete feed (with forage built-in) like Purina® Equine Senior® horse feed is needed. Equine Senior® was designed to contain enough roughage to be fed with minimal or no hay, so that the geriatric horse will receive sufficient nutrients to meet requirements even without an additional forage source. If a horse is still able to chew and digest pasture/hay, switching to a higher calorie feed may be a good choice. Equine Senior® Active is a high-calorie feed that is ideal for older horses that are still able to utilize long-stemmed forage. Ultium® Competition, Ultium® Gastric Care, and Omolene® #500 are other calorie-dense feeds that can help horses gain weight when fed along with good quality hay and/or pasture.

In many cases, the reason a horse is underweight is that they are just not eating adequate calories. First, determine the horse’s current bodyweight by using a weight tape or digital scale. To decide how much weight the horse needs to gain, start with assessing their Body Condition Score.  In general, most horses should be maintained at a body condition score (BCS) of 5-6; broodmares should be 5 to 7.  For every condition score below 5, an 1100-pound horse needs to gain about 45-50 pounds. It takes an additional 8000-9000 kcals above daily maintenance energy requirements to induce 1-pound of weight gain. Multiply 45 lbs (total amount of weight to gain) by 8000 kcals (kcal required per pound of gain) to determine the total amount of additional calories needed for the target weight gain, which in this example would be 380,000 kcals. Obviously, that can’t be fed all in one day! It is best to target a slow and steady rate of gain, and ½ lb per day is a conservative goal. If the horse is to gain 45 lbs over 90 days (1/2-pound gain per day), then an additional 4500 per day above the current ration is required (380,000 kcal / 90 days = 4222.2 kcal/day; round up to 4500 kcal). This could be accomplished many ways, such as adding 2 pounds of Strategy® (3000 kcals) and 2 pounds of alfalfa hay (approximately 1800 kcals) per day or adding 2.5 pounds of Ultium® (4750 kcal) per day. As in all cases, changes need to be made gradually to reduce the risks of digestive upset.