Practical alternatives for managing castration pain in piglets

Abstract

Surgical castration of piglets is a painful procedure used to reduce aggression, sexual behaviours, and boar taint, and is often completed on young piglets. Recent requirements in Canada state that an analgesic must be administered to control the pain of the procedure. The thesis objectives were to evaluate the effects of age and timing of analgesic administration on piglets’ response to castration. Three-day-old PIC Landrace x Large White male piglets were enrolled in study 1 or 2. For study 1, piglets were split into two groups: handling chute and average daily gain (ADG, n=115) or serum cortisol and pen behaviour (n=96), and assigned within litter to six treatments: 1) castration with ketoprofen at 3 days old (YK, n=35), 2) castration with ketoprofen at 10 days old (OK, n=36), 3) castration at 3 days old (YC, n=35), 4) castration at 10 days old (OC, n=35), 5) sham castration at 3 days old (YS, n=35), and 6) sham castration at 10 days old (n=35). From the ages of 9 to 13 days old, older piglets had a higher ADG than younger piglets (0.270.01 kg/day vs. 0.250.01 kg/day respectively, LSMSEM; P<0.05). Serum cortisol concentration 24 hours after treatment was higher in young piglets than old piglets (77.89.2 nmol/L vs. 36.18.9 nmol/L respectively, P<0.05). Older piglets were observed tail wagging at a higher frequency 24 and 25 hours after castration than younger piglets (P<0.05). For study 2, piglets were split into two groups: handling chute (n=76) or serum cortisol and pen behaviour (n=103) and assigned within litter to five treatments: 1) castration with ketoprofen one hour prior (HK, n=37), 2) sham castration with saline one hour prior (HS, n=34), 3) castration with ketoprofen immediately prior (IK, n=37), 4) sham castration with saline immediately prior (IS, n=35), and 5) castration with saline immediately prior (CA, n=36). HK had lower cortisol concentrations than CA, IK, and IS 45 minutes after treatment (90.226.4 nmol/L vs. 206.726.4 nmol/L, 147.525.6 nmol/L, 158.026.4 nmol/L respectively, P<0.05). These studies provide evidence that providing ketoprofen one hour before castration reduces cortisol concentrations and is beneficial to piglet welfare. More research is needed to compare piglet pain responses when castrated at different ages.