Impact of prolonged cow-calf contact on dairy cow production in a pasture-based system

With consumers becoming increasingly concerned about the welfare of farm animals, two aspects of dairy farming have come under scrutiny: cow-calf separation soon after birth and access to pasture. The aim of this study was to investigate the impact of prolonged cow-calf contact (CCC), from birth to weaning, on dairy cow (n=50) production within the context of a pasture-based, seasonal calving system in Ireland. The 3 CCC rearing systems were no contact (control (C), 18 cows), full-time contact (FT), 14 cows; part-time contact (PT), 18 cows). The FT cows and their calves and C cows grazed fulltime; cows were milked twice a day (TAD). The PT cows were milked once a day (08:00), went to grass and returned indoors at 15:00 to join their calves until milking the following morning. All calves were gradually weaned from milk at 8-weeks old. At weaning PT cows switched to TAD milking. Individual parlour milk yield (MY) was recorded daily and average daily milk solid yield (MSY; kg fat + kg protein) was recorded weekly. During weeks 1-8, C, FT, and PT all had different (P<0.001) MY and MSY, during weeks 1-4 MY were 22.1, 13.4, and 9.7 kg/day, respectively, and MSY were 2.1, 1.1, and 0.8 kg/day, respectively. In line with stage of lactation, MY of C (23.9 kg) increased during weeks 5-8 (P<0.001) but decreased for CCC cows (FT: 12.0 and PT: 9.5 kg) and MSY followed the same trend (2.0, 0.9 and 0.7 kg/day respectively). Following weaning (weeks 9-12) FT and PT cows increased MY by 34 and 47%, respectively, and increased MSY by 40 and 51%, respectively, but remained lower (P<0.001) than the C cows (MY: 23.1 kg; MSY: 1.9 kg) for both. From weeks 13 to 35 MY and MSY of FT and PT cows were similar but significantly lower than C (MY: 15.6, 14.9 and 18.8 kg, respectively; MSY: 1.4, 1.3, 1.7 kg, respectively). Over the 35-week lactation C had a higher parlour recorded MY and produced more milk solids than CCC treatments. Further investigation is required to understand the divergence in MY post-weaning