By Mariah Crevier
We explored providing pain control for beef calves castrated by elastration before 1 wk of age. Eighty-five healthy, singleton, bull calves at the Ontario Beef Research Centre were randomly assigned to 1 of 5 treatment groups at birth: one dose of oral meloxicam at castration (1ORAL), one dose of oral meloxicam at castration and a second oral dose 1 wk later (2ORAL), one dose of injectable meloxicam at castration (1INJECT), castrated without pain control (PAINFUL), or not castrated (SHAM). Calves were treated within 48-h of birth and observed 2 h/d for 13 pain-specific behaviours on the day of castration (d 0), and on d 1, 2, 7, 8, and 9. Observers were blinded to the treatment groups and the purpose of the study. From d -1 to 14 each calf wore an Onset HOBO Pendant G Data Logger to record their general activity. Calves were weighed weekly until they were turned-out to pasture, and then weighed bi-weekly until weaning. Data were analyzed using mixed models in SAS, accounting for fixed and random effects. Five behaviours were statistically significant (P<0.05) between treatment groups. PAINFUL calves had roughly three times the rate of licking (P<0.05; F= 6.42; df=163) and twice the rate of tail-flicking (P<0.05; F= 5.96; df=163) compared with meloxicam-treated calves. PAINFUL calves spent the least time standing on average in a 24-h period (P<0.05; F= 2.77; df=478). No treatment effects were seen for average daily gain up to wk 8, or for final weaning weights. Weight at castration was significant factor explaining daily gain (P<0.05), however, calves were not blocked by weight when assigned to treatment. Meloxicam-treated calves expressed lower rates of pain-associated behaviours compared to PAINFUL calves, and weight did not differ by treatment. Results provide evidence that calves castrated by elastration before 1 wk of age and received meloxicam, experience less pain.
