Milking Efficiency – A Milkability Trait for Automatically Milked Cows

Abstract Text: Data from an experimental herd with automatic milkings from 486 first lactation cows were used to study alternative measures of milkability. One trait was milking efficiency, (kg milk per minute used in robot) the other “residual milking box time” using a linear regression to adjust daily time for daily fat and protein corrected yield. Both traits were moderate to highly heritable and closely correlated (r_a = 0.85). The two traits differed by milking efficiency being correlated to yield (r_a = 0.48). Residual box time was closely correlated to milking time (r_a = 0.93) compared to milking efficiency which showed only intermediate correlation. Both traits had weak correlations to somatic cell counts. It is concluded that either trait will be effective in selecting for cows giving more milk per minute occupying the AMS, without increasing risk of mastitis.

Keywords: dairy cattle, milkability, AMS