Star Milling

Estimating A Horse's Body Weight

Heart Girth
Proper use of the weight tape and measuring heart girth circumference

One of the first essential steps in determining the proper feeding program for your horse is to accurately estimate the horse's body weight. Most horse owners estimate their horse's body weight by the “eye method” which can produce errors up to 20 - 25%. A 20% error for a 1000-pound horse could mean an inaccurate body weight estimate as low as 800 pounds or as high as 1200 pounds. There are two simple methods available to horse owners for estimating the body weight of adult horses: the weight tape and the weight table.

Weight Tape: Properly calibrated "weight tapes" are available commercially and most appear to be reasonably accurate within 5-10%. Consistency in technique improves accuracy. Weight tapes are placed around the heart girth. A reference point for the heart girth is approximately 4 inches, or a little more than a "hands-width”, behind the point of elbow. The figure below illustrates the correct use of the weight tape. A frequent mistake is that horse owners will adjust the placement of the weight tape relative to the withers. Do not use the withers as a guide! The weight tape is properly placed if an imaginary line bisects the weight tape (top & bottom) so that the imaginary line is perpendicular to the ground.

Weight Table: Using a non-stretchable material, such as a nylon strap, measure the horse's heart-girth (inches) and compare the measurement to body weights in the corresponding table. The figure below also illustrates the correct method in measuring heart girth circumference.

Heart Girth (inches) Weight (lbs)
30.0 100
40.0 200
45.7 300
50.5 400
55.4 500
59.0 600
62.4 700
65.4 800
68.4 900
70.4 1,000
72.5 1,100
75.0 1,200
77.4 1,300
78.6 1,350
79.9 1,400