The impact of delaying cow-calf separation on dairy cow behavior. 

K. R. Callero*, G. M. Frederick, T. A. Westhoff, and S. Mann, Cornell University, Ithaca, NY.

Recent welfare concerns from the public have brought the practice of immediate cow-calf separation into question, however, there is a lack of research observing the behavior effects of delaying cow-calf separation. Thus, the objective was to describe cow behavior when calf separation was delayed in the first week postpartum. We conducted a block randomized controlled trial with treatments stratified by parity (primiparous vs. multiparous). Holstein dairy cows were allowed to maintain contact with their newborn calf for 0 (0D; n = 6), 3 (3D; n = 5), 5 (5D; n = 6), or 7 d (7D; n = 6). After parturition, all enrolled cow-calf pairs were moved from the maternity pen into identical individual box stalls with an attached calf pen and remained there for 8 d of observation during which they were milked 2?--/d. Non-contact groups were physically separated by a solid barrier. Continuous audio and video recording and measurement of activity with cow leg sensors was performed. Heart rate monitors were placed on each cow for 4 h after morning milking on the day before and the day of separation. Video data were analyzed in a subset of 16 cows (0D, n = 4; 3D, n = 3; 5D, n = 4; 7D, n = 5). Behavioral Observation Research Interactive Software (BORIS) was used to code footage of enrolled cows 24 h before and 24 h after separation. Heart rate data were analyzed in MATLAB and activity monitor data were analyzed in SAS. All other data manipulation was performed in Excel. All cows who had contact with their calves did not reject them, spent time grooming them and there were no calf injuries observed. Cows in the 5D and 7D groups had increased number of vocalizations (P = 0.006) after separation as compared with those in the 0D and 3D groups. The 5D group also had a higher difference in heart rate standard deviations (P = 0.04) than other groups. By observing cows and their calves together for 3, 5, or 7 d, we described aspects of a cow's behavioral response to delaying separation. Our results suggest that cows have a measurable behavior response to delayed separation, and additional research is necessary to understand possible influences on health and welfare.