Use this estimate when the species, measurement method, body-size range, and units match the relationship implemented by the tool. It is most useful for screening, normalization, or comparing repeated measurements made under the same protocol.

Body mass

Body mass in kilograms; must be greater than zero.

The implementation follows this calculation rule: Estimate basal metabolic rate across animals with Kleiber's law: BMR = 70 x bodyMass^0.75 kilocalories per day.

Basal metabolic rate

Basal metabolic rate in kilocalories per day.

Allometric and livestock equations are empirical relationships, not direct measurements. Breed, age, sex, condition, hydration, posture, and the population used to fit the coefficients can produce systematic error. The output is explicitly an estimate or proxy; preserve that label when reporting it.

Prefer a calibrated scale or direct laboratory measurement when available. For longitudinal work, pair the estimate with condition score, age, and repeated measurements collected by the same operator.

• Brain Allometry Slope

  Predict brain mass from body mass with the allometric power law predictedBrainMassG = 10^(intercept + slope x log10(bodyMassG)); defaults use intercept -1.0 g and slope 0.75 for the vertebrate brain-body scaling line.

• Body Length Weight

  Estimate cattle weight in kilograms from body length and chest girth with the same-family length formula.

• Chest Girth Weight

  Estimate cattle weight in kilograms from the chest girth with the documented cubic approximation.