Animal performance and stress at weaning when dairy cows suckle their calves for short versus long daily durations

Calves in most European dairy farms are separated from their dams either immediately or within a few hours after birth, prompting mounting society concern on animal welfare grounds. The aim of this study was to identify ways to maintain cow–calf contacts that balance the benefits for calf growth and health against the negative impacts on saleable milk and stress at weaning. We tested reuniting cows and calves for 20 min before ( Before group) or 2.5 h after ( After group) morning milking (Trial 1) or for a 9 h period between the morning and evening milkings (Dam group, Trial 2). In both trials, each treatment was applied on a group of 14 dam–calf pairs (7 Holstein [ Ho ] and 7 Montbéliarde [ Mo ]). Control -calves were separated from their dam at birth and artificially suckled with tank milk provided daily at 13% (Trial 1) and 14% (Trial 2) of their body weight. All calves were weaned from the age of 12 weeks at a weight of at least 100 kg. In Trial 1, the After group was prematurely stopped when the calves were 8 weeks of age as calf growth became limited (318 g/d) due to low milk intakes (3 kg/d). Milk yield at the parlour was 29% lower in After-cows compared to Controls (first 8 weeks of lactation). During the first 16 weeks of lactation, milk yield at the parlour was 45% lower in Before-cows and 31% lower in Dam-cows compared to Controlcows. Milk protein content was 2.1 g/kg higher in Before-cows and 1.3 g/kg higher in Dam-cows while milk fat content was 3.2 g/kg higher in Before-cows but 5.2 g/kg lower in Dam-cows compared to Control-cows. There were no significant differences in milk SCC and in frequency of cow and calf health events between suckling and control groups. Compared to Control-calves, calf growth until weaning was higher in the suckling calves in Trial 1 (+171 g/d in Before-calves) and similar in Trial 2 (+7 g/d in Dam-calves). At weaning, Before- and Dam-calves started to vocalize earlier and continued to vocalize longer than controls. In conclusion, the best compromise between cow milk yield and calf growth is a long period of cow–calf contact (9 h) between the morning and evening milkings. Still abrupt weaning nevertheless stresses both cows and calves