Effects of previous handling on responses of dairy calves during painful procedures
Reducing stress during routine husbandry procedures may have potential for improving animal welfare. However, few studies have investigated the influence of previous handling before procedures are performed. We investigated the effects of different types of handling on responses of dairy calves during cautery disbudding with local anaesthetic and ear-tagging. Forty Holstein-Friesian calves were exposed to either positive (e.g. soft voices, slow movements, patting) or negative (e.g. rough voices, rapid movements, pushing) handling (n=20 calves/treatment), twice daily (7 min/session) from 4 days to 5 weeks of age. At 5 weeks of age, calves were ear tagged and then disbudded 2 days later. Respiratory rate (RR), heart rate (HR), heart rate variability (HRV) and struggling behaviour were recorded continuously 5 min before and 5 min after each procedure. In addition, eye temperature (measured using infrared thermography) was recorded before and after ear-tagging. REML was used to detect treatment differences. There were no significant treatment differences in struggling, eye temperature, RR, HR or HRV in response to either procedure (P=0.493). However, the following changes (mean±SEM) occurred across both treatment groups: 1) there was an increase in struggling (by 9.4±1.2 and 9.9±1.3 events/min, positive and negative respectively, P<0.001) and RR (by 8.2±3.4 and 9.3±3.3 breaths/min, positive and negative respectively, P<0.05) after disbudding, 2) HR increased after disbudding (by 14.7±4.0 and 18.6±3.8 beats/min, positive and negative respectively, P<0.001) and ear-tagging (by 8.7±3.1 and 10.3±3.0 beats/min, P<0.01), 3) changes in HRV parameters indicated a general increase in sympathetic activity after disbudding (P<0.05). In conclusion, type of handling had no significant effect on responses to disbudding or ear-tagging. The effects of handling may have been overridden by the pain and/or stress associated with the procedures. Further research is warranted to understand the welfare impact and interaction between previous handling and responses to husbandry procedures.