| Animal traction |
|2. Draft animal selection|
To determine an animal's weight, first measure the length of the animal from point of shoulder to point of rump (A-B) and the circumference of its torso at point of heart (C) with a tape or rope. (See the drawing on page 20.) When taking the torso or girth measurement, observe these rules:
• Measure in the morning before the animal drinks. Don't give it hay the night before.
• Have the animal stand squarely with its head in a normal position.
• Pull the tape snugly around the torso, at the smallest circumference behind the shoulders.
Next, follow these formulas:
For bovine animals
Substitute measurements A-B (length) and C (circumference of torso at point of heart, or girth) into this formula:
(girth x girth x length)/300 = weight
For this formula, measurements must be taken in inches. If a metric tape or rope/rule is used to measure the animal, centimeters must be converted to inches before the formula can be used. One inch = 2.54 cm.
Girth of bull measures 152 cm, length measures 135 cm.
152/2.54 = 60 inches (girth)
135/2.54 = 53 inches (length)
(60 x 60 x 53)/300 = 636 lbs
Since one kg = 2.2 lbs, the weight of the animal in kg is obtained by dividing 2.2 into the answer above (636 lbs).
636/2.2 = 289 kg
The bull weighs 636 lbs or 289 kg.
An alternate method for estimating the weight of a steer (castrated bull):
Live weight • 1.04 [27.5758 x heart girth) -1.04967]
Substitute measurements A-B (length) and C (girth) into this formula:
(girth x girth x length)/300 + 50 lbs = weight
Measurements must be taken in inches, or converted into inches, before the formula is used.
Donkey's girth measures 37 inches, donkey's length measures 35 inches.
(37 x 37 x 35)/300 + 50 = weight of donkey
160 + 50 = 210 lbs
If the animal's weight is to be expressed in kg,
210/2.2 = 95 kg
The donkey weighs 210 lbs or 95 kg.