Even without scales, farmers can use a measuring tape to calculate the weight of cattle. After measuring the chest circumference, farmers then calculate the weight of the cattle using a formula.
1. Calculation method
To calculate a cow's weight using a measuring tape, first measure the cow's body length and chest circumference. Then, estimate the weight using the formula. Body length is the curved distance from the anterior edge of the shoulder to the posterior edge of the ischial tuberosity, measured in centimeters using a measuring tape or tape measure. Chest circumference is the length measured vertically around the chest at the posterior angle of the scapula or the posterior edge of the cubital process of the forelimb, also measured in centimeters using a measuring tape or tape measure.
Taking the calculation of weight using the size of a cow's chest as an example, with a chest circumference of 150cm and a live weight of 300kg as a base, when the chest circumference is less than 150cm, the live weight = 300 - (150 - actual chest circumference) × 5, while when the chest circumference is greater than 150cm, the live weight = 300 + (actual chest circumference - 150) × 5.
2. Calculation formula
Calculating the weight of draft cattle: Live weight (kg) = (Chest circumference × Chest circumference × Body length) ÷ 10800. The units for chest circumference and body length are centimeters.
Measuring the weight of beef cattle: Live weight (kg) = (Chest circumference × Chest circumference × Body length) × 90. Chest circumference and body length are in meters.
3. Weight calculation for different cattle breeds
① Fattening cattle
Calculation method: Weight (kg) = Chest circumference (m)² × Body oblique length (m) × 87.5
②Unfattened cattle
Calculation method: Weight (kg) = Body length (cm) × Chest circumference (cm) × Coefficient ÷ 100
Coefficient: The coefficient for beef cattle is 2.5, and the coefficient for dual-purpose cattle is 2.25.
③ Yellow cattle
Weight (kg) = Chest circumference (m) squared × Body slope length (m) × Estimation coefficient
Estimated coefficients: 12,500 for 6-month-old cattle, 12,000 for 18-month-old cattle.
4. Precautions
It is recommended to measure chest circumference 12 hours after feeding and watering. With the cow standing upright with its head facing forward, the soft measuring tape can be placed behind the shoulder and close to the fur to measure the minimum chest circumference.
