Caring for the Underweight Horse

By Marcia Hathaway, Devan Catalano and Krishona Martinson
 

It’s rare to see a healthy horse that’s too thin since thin horses may be at higher risk for health problems. Before setting up a feeding and management plan for a thin horse, determine why the horse is thin by working with an equine veterinarian and nutritionist.

Determining if your horse is underweight
The two most common ways to assess your horse’s body condition and body weight are body condition scoring and ideal body weight equations.

Body condition score
Body condition scoring (BCS) evaluates the fat deposit under the horse’s skin in six areas.

• Neck
• Withers
• Behind the shoulder
• Along the back
• Rib area
• Tail head

BCS uses the Henneke scale: 1=poor; 9= extremely fat. The ideal BCS for most breeds and disciplines is 5, but ranges from 4 to 6.

A horse with a score of 4 is considered healthy, but it’s important to look at the overall picture. Has this horse lost body weight and dropped from a score of a 5 or 6 to a 4? Is it an older horse or one without a good hair coat going into winter? These may be reasons to put body weight on a horse.

Horses scoring 3 or lower are underweight or thin. In situations of extreme neglect or poor health with a horse that scores 1 or 2, we recommend working with a veterinarian or equine nutritionist to create a re-feeding plan.

Ideal body weight equations

Researchers at the University of Minnesota developed ideal body weight equations to help determine your horse’s ideal body weight based on his or her overall frame.

To calculate your horse’s ideal body weight you need the following measurements:

• Height, from the top of the withers
• Body length, from the point of the shoulder to a line perpendicular to the point of the buttock. Don’t wrap the tape measure around the buttock.

Causes and possible solutions
 

Not enough calories

The horse’s digestive system makes forages their ideal source of energy. Thus, you should minimize or avoid feeding large amounts of grain if possible.

If your horse is thin without any underlying health issues, and simply needs more calories, you can fix the problem by:

1. Allowing 24/7 access to pasture or hay (or as much forage as possible).
2. If increased amounts of hay aren’t enough, try offering a higher quality hay such as alfalfa or an immature grass hay.
   • Alfalfa tends to be higher in energy and protein and lower in sugar.
   • Alfalfa can be fed as hay or as cubes/pellets.
3. If you aren’t feeding any grain, try adding a grain product meant for working or performance horses.
   • These grains will contain higher levels of protein and fat that will aid in body weight gain.
4. If you are already feeding grain, instead of feeding more, try switching to a performance feed product with 10 to 12 percent fat.
   • Using fat to increase the energy in a ration can help reduce temperament changes seen in some horses eating large amounts of starch or carbohydrates.
5. If you are unable to change the grain product, add a high-fat supplement to your horse’s regular ration such as:
   • Rice bran
   • Flax seed
   • Vegetable oil
   • Dried granular fats