Estimating Horse Body Weight
Dr. Robert E. Bray, Star Milling’s Consulting Equine Nutritionist
(Permission granted for the reprinting of this material from REBray’s Equine Nutritional Management© manual for the 2012 Star Milling website)
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| 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. A 1000-pound adult horse fed hay at 1.5% of his body weight would be fed 15 pounds of hay per day; …for an 800 pound horse, 12 pounds of hay; and for a 1200 pound horse, 18 pounds. If you have become proficient in body condition scoring then of course you would soon noticed that your horse is either loosing or gaining body weight because of the inaccurate body weight estimate. 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 can provide accuracy within at least 5%. 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.
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Heart Girth
(inches) |
Body Weight
(lbs) |
30.0
40.0
45.7
50.5
55.4
59.0
62.4
65.4
68.4
70.4
72.5
75.0
77.4
78.6
79.9 |
100
200
300
400
500
600
700
800
900
1,000
1,100
1,200
1,300
1,350
1,400 |
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| Proper use of the weight tape and measuring heart girth circumference |
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