Exploring factors influencing machine milk yield of dairy cows in cow-calf contact systems: Cow behavior, animal characteristics, and milking management.

The objective of this study was to explore factors contributing to low machine milk yield of cows with cow-calf contact. Danish Holstein dairy cows were assigned to 1 of 3 cow-calf contact treatments: full-time with the calf (n = 24), part-time with the calf between morning (a.m.) and afternoon (p.m.) milking and separated overnight (n = 23), or separated from the calf at birth (n = 23). Behavior of cows (stepping and kicking in the parlor) and milking procedures (teat or udder stimulation frequency, preparation duration) were recorded at a.m. and p.m. milking on 2 d during wk 4 and 6 of the treatment period (8 milkings per cow). Full-time cows had the lowest machine milk yields (mean ± SE; 6.1 and 6.0 ± 0.7 L at a.m. and p.m. milking, respectively), whereas part-time cows had similar yield to no-contact cows at a.m. milking (19.6 ± 0.7 L) and similar yield to full-time cows at p.m. milking (6.4 ± 0.7 L). Lower machine milk yields in cows with calf contact could not be fully attributed to milk consumption by the calf; however, they also could not be explained by differences in cow parity, calf sex, milking procedures (stimulation frequency; preparation duration), or stepping and kicking (restless) behavior at milking. All cows showed more restless behavior at p.m. milking, which weakly negatively affected machine milk yield, but this was unrelated to stimulation frequency in cow-calf contact cows, indicating that there may be other sources of discomfort or stress at the time of milking for these cows. Part-time versus full-time calf contact improved daily machine milk yields, but low machine milk yield issues merit further research so that cow-calf contact systems can be sustainable for producers.