The biometry of lactation

Abstract

A consideration of input-output relationships relating energy intake to its probable utilization for growth, condition and lactation by dairy cows leads to a series of equations describing observable responses. Energy is expressed in terms of units of milk equivalent, common to all equations, and the lactation curve, yn = anò e−cn is shown to be capable of biological interpretation, having regard to the subordinate equations from which it is derived. This expression relates milk production yn during a time interval n through the parameters a, b and c. The validity of the steps by which the function is developed is examined by reference to published work.