Effects of cow-calf contact during the first week and following separation on cows' behavior, feed-related...

Dairy farming systems are viewed critically by animal welfare-oriented consumers due to the rapid disruption of the maternal bond caused by immediate separation after birth. Cow-calf contact systems are therefore considered to be a more welfare-friendly alternative, offering varying contact durations and management strategies. One approach in cow-calf contact systems is the use of foster cows for calf rearing, typically introduced within or after the first week of a calf's life. However, separation after a cow-calf contact period may alter animals' behavior. This study examined the effects of cow-calf contact during the first week and following separation, focusing on cows' activity, lying behavior, feeding parameters, and milk yield and composition. The study was carried out at the Technical University of Munich (TUM) experimental farm Veitshof (Freising-Weihenstephan, Germany) with 20 Brown Swiss cows distributed equally between an early-separation group (ESG) and a cow-calf contact group (CCC). In ESG, cows were separated immediately (≤2 h) after birth, whereas in CCC they remained with their calves until the morning of d 8 after birth. Pedometers and neck collars were used to track activity, lying behavior, and feeding patterns. Milk yield and composition were also recorded for cows. Cows in ESG were reintegrated into the lactating herd on d 8 after calving, after spending the same amount of time (d 1-7) in the calving area as the CCC cows. A mixed-effects model was used, with group and time as fixed effects and cow as a random effect. The results showed that cows in ESG exhibited lower daily activity impulses on d 8 to 10 compared with cows in CCC. In ESG, lying time declined from d 2 through 7 to d 8 through 10, as cows were reintegrated into the lactating herd. The CCC group exhibited a stronger reduction in lying time after separation, reaching pre-separation values again on d 10. Feed intake time and rumination time were time-dependent, with ESG cows maintaining more stable rumination time values, whereas CCC cows exhibited a reduction after separation and a peak in feed intake time on d 9. Milk yield was consistently higher in ESG, whereas CCC showed more pronounced temporal variation. In CCC, milk fat, lactose, and urea concentrations were lower during the early phase but increased toward the end of the study period. In contrast, milk composition in ESG remained largely stable, apart from generally higher milk pH, but SCC was higher in CCC on d 7. Overall, separation after 1 wk of cow-calf contact triggered behavioral and performance related changes, with potential impairments to the energy balance, particularly due to higher activity and reduced rumination time.