Published April, 2011

Body condition scoring (BCS), an impartial way to evaluate a horse's weight and welfare, is a valuable tool that helps horse owners understand their horses' well-being. It is an important aid that can be used to make sound decisions regarding general management, including feed and exercise levels.

Horses normally lose weight in the winter and gain in spring, summer, and fall. "We manipulate their weight with feed, blanketing, exercise, and management," Fernanda Camargo, DVM, PhD, assistant professor and equine extension specialist at the University of Kentucky, reminded her audience at a recent seminar held by UK. "That is why fat horses don't lose weight in the winter."

The system widely used today to evaluate equine body condition was developed about 30 years ago by Don Henneke, PhD. He developed BCS while he was a graduate student at Texas A&M University.

"It is an impartial numerical system that evaluates a horse's condition. The size of the belly is not important," Camargo said. "As you evaluate the BCS of a horse, develop a system and follow it each time."

A horse receiving a score of 1 is emaciated. A 9 is grossly overweight. A horse in optimal condition should receive a 5 or 6. In certain disciplines, such as racing or endurance, horses are kept leaner, closer to a 4, like marathon runners. A 50-pound weight gain or loss is roughly the change from one number to the next.

All horses can be body scored, even late pregnancy mares, and it is a myth that broodmares need to be fattened up. Camargo drew a laugh from the crowd as she compared mares to women, pointing out similar pregnancy issues: joint pain and pressure and fluid retention.

"Pregnant mares should gain weight but should be kept at an optimum BCS of 5 or 6," she said.

Adjusting Feed Levels for Overweight Horses

For overweight horses scoring 7, 8, or 9, Camargo recommended feeding changes, but cautioned owners not to eliminate all food. Horses still need to eat to lose weight--they need feed intake for their metabolism to work properly. A horse in this category does not need grain but, rather, a forage diet.

She asked if anyone in the audience had a fat horse, and then, as several hands went up, she asked if any fed grain. The hands stayed up.

"Grain is a human need, not an equine need," she explained.

Horses need to be fed approximately 2% of their body weight per day. For example, feed 20 pounds of feed (hay and grain combined) if a horse weighs approximately 1,000 pounds. However, a fat horse most likely will not need grain. Therefore, feed about 20 lbs of hay only, and provide a vitamin and mineral supplement.

Other equine weight loss steps Carmargo recommended include:

• Change to a lesser quality (but not moldy or dusty) hay. Lesser quality hay has been harvested at a later stage than shorter, high--nutrient hay but it will still be sufficient to keep your horse's digestive tract working.
• Limit access to pasture, which has a lot of sugar and calories. Use a muzzle if your horse will accept one. Keep in mind that horses need to be muzzled most of the day, not just a few hours.
• Turn out in a drylot and feed only hay.
• Exercise. If your horse is being ridden he will burn calories. Start with incremental exercise to build muscle and reduce the possibility of soft tissue injury. For example, you might longe at a trot for 20 minutes for one week. In week two longe for 20 minutes at both a trot and canter. Continue to build upon this schedule until you can start riding your horse. Remember to increase the time or the level of exercise, but not both at the same time.

Increasing Feed Levels for Underweight Horses Scoring Below 4:

• Change to a good quality hay. Good quality hay has been harvested at a young stage and will appear leafy and green. Clover hay is the exception; it is brown but still high quality. Alfalfa is a good choice because of its high protein and calorie content. A legume hay (for example, clover or alfalfa) has more calories than a grass hay.
• Increase the amount of hay. At least half (1% of their body weight) of a horse’s intake needs to come from forage.
• Increase water. Horses need access to water at all times, but they will need even more if fed a high protein diet.
• Start feeding grain. Buy good quality grain from a reputable source. (Caution: If you buy from a small feed mill, ensure they are not concurrently milling cow supplements, because small amounts that end up in horse feed could be fatal.)
• Decrease exercise. A thin horse needs to expend less energy/calories than he is bringing in via feed.
• Add oil (vegetable, canola, soy, rice, bran, corn), which is high in calories and can easily be added to grain.
• Check your horse's teeth to ensure they are in good condition, and have them floated if necessary.

Feeding Severely Underweight or Starved Horses:

• Introduce feed slowly. The digestive tract needs time to acclimate and start working again.
• Feed small amounts often. Start with one flake of a grass-hay mix five to six times a day.
• Check manure for telling signs of problems. Of concern is manure that is hard and dry or manure that is loose like a cow pie.
• Have patience. Saving a starved horse can take months, during which it may only slowly regain condition.

Karin Pekarchik is an editorial officer in Agricultural Communications Services.