Is Your Horse Overweight?

Carrying excess poundage is a serious health issue for any species but when your normal weight is already 800+ pounds the problem is magnified.

Even if pregnant, these horses are grossly obese

Remember basic physics?  Force = Mass x Acceleration. Mass is your horse’s weight.  The stress experienced by the skeletal system, the heart and the lungs is directly proportional to the horse’s weight. Even standing still the pull of gravity has a greater toll on the heavier individual.

A 2017 Canadian study (Kosolofski et al) found 28.6% of horses were overweight or obese.  A 2016 Australian study (Potter et al) found a similar picture in horses with 23.1% overweight or obese but pony types other than Shetland higher at 32.1% and Shetlands led the list at 71.5%. Most owners significantly underestimated how much excess body fat their animals were carrying.

In the United States, a 2018 study in Maryland (Jaqueth et al) also found a serious problem. Of ponies, 41% were overweight or obese and the same was found for 40% of the surveyed full size horses.

Consistent among studies is that owners do not know how to evaluate their animals’ weight.  The first step in correcting this is to become familiar with the Henneke body condition score: .

Many might call this horse too thin but in reality he is a perfect body condition score 5.

The horse’s structural conformation, muscle bulk and muscle tone can lead to mistaken evaluations of body condition score but these are less likely if you carefully follow the Henneke system since it is designed to specifically evaluate the amount of body fat the horse is carrying.

Some specific tips and precautions include:

  • Breeds which have a naturally thick or high set neck should be evaluated first without looking at the neck. Wide necks are not necessarily fat.
  • Very heavily muscled breeds may have a crease down their back at normal body condition scores
  • The body bulk should be proportional to the size of the muscle mass at the upper leg/forearm/gaskin.  The body should not look like it’s perched on toothpicks.
  • Except for heavily pregnant mares or horses with abnormally enlarged abdomens, the ribs should not be visible but should be easily felt

While horses do vary somewhat in how easily they gain weight, the bottom line is still always that if calories in is higher than calories burned the horse will gain weight.  The rule of thumb for weight loss is to feed the horse grass hay at a rate of 1.5% of his current weight or 2% of the ideal weight, whichever is larger.

This applies to average grass hays and some may be more calorie dense, requiring a reduction in amount fed. Alfalfa is more easily digestible so will increase the calorie yield per weight of hay fed.  Horses needing to lose weight should never be fed  grain.  Balancers are also higher calorie and should be calculated in the daily ration assuming 1 lb of balancer = 2 lbs of grass hay.

If you are starting an exercise program with your overweight horse, go slowly to avoid joint or tendon/ligament injury. Do not increase calorie intake until the horse has reached and started to go below the target weight.

Horses on a diet must have pasture intake severely limited or prevented with a muzzle. If not losing on the calculated amount of hay, he’s getting too much grass. Ideally, hay should be analyzed to guarantee adequate protein and identify mineral deficiencies or imbalances. Top off the hay diet with a mineral supplement compatible with the hay’s profile, 4 oz of flax seed, 1 to 2 oz of salt and 2000 IU of vitamin E.

Remember, while many horses will overeat if given the opportunity, you are in control. He relies on you, not will power, to protect him from excess weight.

Eleanor Kellon, VMD




About Dr. Kellon

Graduate of University of Pennsylvania Veterinary School. Owner of Equine Nutritional Solutions,, industry and private nutritional consultations, online nutritional courses. Staff Veterinary Expert at Uckele Health and Nutrition.
This entry was posted in Equine Nutrition. Bookmark the permalink.

1 Response to Is Your Horse Overweight?

  1. Susan hidalgo says:

    A challenge. Ty very much.

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