From AAEP’s Ask the Vet: Horse Needs to Gain Weight
I have had my mare for 3 years and I can’t seem to get her to gain weight. She is scary thin no matter what or how much I feed her. I love my horse a lot and have never ridden her because of this problem. Why won’t she gain weight and keep it on?
I can tell you’re very concerned about your mare so let’s see what we can do to help her. First of all, how old is she? There are different reasons why a young, middle-aged, or senior horse may have trouble keeping weight on.
Have you had a veterinarian examine her? A complete physical examination—which may include bloodwork, a fecal, a dental exam and other specific tests—could rule in or rule out specific health conditions that may be responsible for her thin body condition.
Speaking of body condition, have you or someone else officially scored her? The horse industry uses the Henneke Body Condition Scoring scale as a standardized, uniform system for assessing the fat cover on horses. The scale ranges from 1 (emaciated) to 9 (obese), with 5 being moderate or ideal. It may also be a good idea to regularly weigh her with a weight tape and record these two separate measurements so you have an objective record of changes or trends.
Next, I strongly recommend you weigh everything you feed your mare now: hay, grain, etc. You may find out that you’re not supplying her with the recommended 2% of her body weight each day in hay, or that you haven’t been giving a full serving of grain as recommended on the bag.
Environment can have a lot to do with how well and how much horses eat. For example, if she primarily eats meals in a stall where she can’t see any other horses, she may be either too stressed to eat or burning every calorie she’s taking in worrying about being alone. On the other hand, if she’s at the bottom of the herd pecking order and having to scramble for every morsel of hay and grain, she may be using up valuable energy scrounging for her food.
Once you’ve addressed all these issues, it’s time to experiment with different forages such as alfalfa hay, cubes or pellets; calorie-adding feeds such as beet pulp and rice bran; and specific ingredients like fat and amino acids. Your mare may benefit from digestive support that improves her digestive efficiency, helping her extract the most nutrition possible from what she’s already eating.
You certainly have your work cut out for you, I hope the “homework” I have provided yields some answers for you!