I was called out to farm to review a horse that had started to lose weight.  The owner explained to me that the horse had been diagnosed with ulcers, so her vet recommended alfalfa hay. She purchased some nice quality second cutting, and had the test results which showed the hay to be exceptional quality, and containing 1Mcal (1000 calories) per pound. Thus, she could not figure out where the hole in the feeding program was that was causing the horse to lose weight. 

In review, her horses diet was calculated at 21.5 Mcal per day, based on his work schedule and body condition score:

• 4 flakes of timothy hay per day
• 4 pounds of grain  per day

Since the horse weighed in at 1000 pounds, we chose to go with 2% of his body weight per day in forage, or 20 pounds.  The old hay had tested at 800 calories per pound. We balanced the diet with 4 pounds of grain at 1430 calories per pound, or 1.43 Mcal.

• Forage = 16 Mcal
• Grain = 5.7 Mcal
• Total = 21 .7 Mcal

The owner explained that she was feeding the same amount of hay as before, and since it was such good quality, it had to be a grain problem.

When we calculated his old diet, each flake of hay averaged 5 pounds each.  That was how we determined 4 flakes would reach the 2% or 20 pound feed rate.  I asked if she had weighed the new hay, and she admitted she had not done so yet.

To her surprise, when we weighed several flakes, they all averaged 3 pounds per flake.  When I showed her the math, the problem was obvious:

• 1 Flake timothy hay 5lb@ x 4 flakes per day = 20 pounds per day x 800 calories = 16Mcal  (16,000 calories)
• 1 Flake Alfalfa hay 3lb@ x 4 flakes per day = 12 pounds per day x 1000 calories = 12Mcal (12,000 calories)

With that simple change in hay, she had cut her horse’s caloric intake by 4,000 calories per day over the past month. Armed with this new information, adding more flakes of hay to the daily ration put the horse right back on track.