Behavioral and physiological changes in early-weaned multiparous and primiparous beef cows.

Early weaning is used to advance postpartum ovulation in beef cows, but triggers a stress response, affecting cows' and calves' welfare. Our aim was to compare the response to early weaning in multiparous and primiparous cows. Seventy-one days after birth, calves from 14 primiparous and 11 multiparous cows were weaned. Since birth, cow's body weight (BW), body condition (BC), milk yield and calves' BW were recorded. Basophil/neutrophil relationship, total protein and albumin concentrations were measured before and after weaning. The distance between each cow and its calf before weaning, as well as main behaviors of the cows before and after weaning were recorded using 10 min scan sampling. BW and BC were greater in multiparous than in primiparous cows (P < 0.0001 for both). There was an interaction between parity (P = 0.004) and gender of the calf (P = 0.007): both BW and BC were greater in multiparous than primiparous cows, but multiparous cows with male calves had lower BW and BC than those with females (P < 0.001 for both variables). Milk yield was greater in multiparous than in primiparous cows (P = 0.02), and there was an interaction, with greatest milk yield in multiparous cows that calved males (P = 0.02). Total protein blood concentration increased with time (P < 0.0001), similarly in both groups. Albumin concentration profiles were similar despite parity, and decreased since 10 days after weaning (P < 0.0001). Basophil/neutrophil ratio was not affected by parity, and increased the day of weaning, remaining high until day 10 (P < 0.05). Frequency of standing decreased during the 2 days after weaning, with a greater decrease in multiparous than in primiparous cows (P < 0.0001). Pacing increased after weaning (P = 0.001), but increased significantly more in multiparous cows (P = 0.006), with a significant time after weaning by parity interaction (P = 0.01) reflected in greater frequencies in multiparous cows in the 2 days. Walking increased with time (P < 0.0001), and was more frequent in primiparous cows (P = 0.008). Ruminating, which was less frequent in multiparous cows (P = 0.014), decreased and remained low during the 3 days following weaning (P < 0.0001), but there was a significant time by parity interaction (P < 0.0001). The frequency of vocalizations increased dramatically after weaning (P < 0.0001), and was greater in multiparous cows (P = 0.006), and decreased more slowly during the 2nd and 3rd days after weaning (P = 0.005) in these animals. In conclusion, behavioral changes induced by weaning were greater in multiparous than primiparous cows, indicating a more intense response to cow-calf separation in the multiparous animals.