Feeding the Underweight Horse

There are many reasons a horse may be losing weight or be underweight. The first step in helping your horse gain weight is to investigate the underlying cause of the weight loss. Once medical or management causes of poor weight are addressed or ruled out, changes in diet may also be warranted.

How Do I Know if my Horse is Underweight?

The Henneke Body Condition Scoring System is a standardized approach to evaluating the horse’s energy balance. This system rates a horse’s body condition score (BCS) from a 9 (extremely fat) to a 1 (extremely emaciated). Horses are generally considered healthy if they are maintained in a range of 4 to 6. If your horse is under a BCS of 4, they are considered underweight and a BCS of 4 is often too thin for many disciplines.

There is more to evaluating the appearance of the horse than just a body condition score, which only evaluates the fat covering of the horse. So, we have developed the Tribute® Wellness System, which gives a more holistic picture of the horse’s nutritional status. Using this system, we assess BCS, topline muscling and crest scoring, which can indicate potential metabolic conditions.

Why Are Some Horses “Hard Keepers”?

There is variation in the basal metabolisms between individuals, meaning that two horses that are the same size, given the exact same diet and in the exact same level of work may have different BCS. Horses with a higher basal metabolism will require more calories to maintain their body condition as compared to the easy keeper.

Having a horse with a higher metabolism is not an excuse for a horse to be underweight. It is also important to note that some horses labelled as “hard keepers” may have another underlying condition making it difficult for them to gain or maintain weight.

Why is My Horse Losing Weight?

There are many reasons a horse may be losing weight.

  • Illness. If a horse was in a healthy body condition and then suddenly starts losing weight, it may indicate illness. It would be advisable to speak to your veterinarian.
  • Parasitic infection. A good deworming plan is critical, as intestinal parasites often lead to weight loss.
  • Poor dental health. Sharp points on the horse’s teeth or other issues can cause horses to not eat. Thus, like parasites, a good dental health plan is critical.
  • Stress. For horses, stress can come in many forms, including weather, social stress, exercise stress, and even stress due to seasonal flies and other insects.
  • Gastric ulcers or hindgut dysfunction. The digestive system is less efficient at digesting and absorbing nutrients when it is unhealthy.
  • Poor diet. Feeding poor-quality hay or feeds can lead to weight loss.
  • Under feeding. Failing to feed adequate quantities of even good quality forage or horse feed can result in an underweight horse.
  • Age. As horses get older, their digestive systems become less efficient and their dentition declines*.

*Note: Age is not an excuse for a horse being underweight. Older horses may have developed underlying conditions or require a different diet or feeding management strategy to maintain weight.  

What Is the Best Feed to Put Weight on a Horse?

First, identify why your horse is underweight and alleviate any non-nutritional causes. Then, attention can be turned to adjusting what you are feeding your horse to add weight. It is important to note that horses that are under a BCS score of 3 need additional, special care. We ask that you contact us for expert advice in these circumstances. Emaciated horses need to be carefully nurtured back to a proper weight.

Maximizing the calories your horse is consuming from their forage is the first step to designing a diet for the underweight or hard keeper.

forage analysis is a good start to determine a forage’s quality. Ideally, the underweight horse will have free choice access to high quality hay but should be offered at least 2% of their body weight in forage per day. For a 1000 pound horse, this would equal to 20 pounds of forage daily.

Good quality pasture can be an excellent source of forage in the horse’s diet; however, it is important to ensure the pastures are properly maintained and productive. An overgrazed pasture or dormant winter grass is not a good source of calories. When a pasture is not productive, a high-quality hay must be provided. For senior horses or horses that have difficulty eating forage/pasture, supplementation with a high fiber horse feed is always a good option.

Building off a foundation of good quality forage (and plenty of it!) is choosing the right horse feed. Choose a feed that provides calories through high quality fiber and fat, instead of high sugar and starch ingredients that can contribute to digestive dysfunction.

Feeds to Consider in the Tribute Superior Equine Nutrition® Line for Hard Keepers or Underweight Horses:

Supplements to Consider in the Tribute Superior Equine Nutrition® Line for Hard Keepers or Underweight Horses:

For some final tips, it is always important to remember to slowly change your horse’s diet. In some cases, especially in aged horses, feeding them more often may help them optimize digestion. Once your horse reaches their desired BCS and other targets via the Tribute® Wellness System, you can then consider decreasing their feed for maintenance of their target goals.

If you are concerned about your underweight horse and would like guidance on a Tribute Superior Equine Nutrition® feeding plan, please contact us today!


Article By: Chris Mortensen, Ph.D.
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