521. Normal variations in the rate of machine milking

Abstract

1. A study has been presented of the machine milking rate of 141 cows recorded in 326 lactations. 2. The coefficients of variation between cows of various measures of machine milking rate are usually in the range 30–40%, whilst the within-cow variations are of the order of 8–11%. 3. The differences between the milking rates of cows in a single herd are given, together with the distribution of these differences. 4. Milking rate declines as lactation advances, the decline being greater for fast milking cows. 5. Lactation decline in milking rate is related independently to change in milk yield and to interval since calving.