Abstract #M28

# M28
Effect of surgical and band castration on indicators of chronic pain in 0-, 2-, and 4-month-old beef calves.
Sonia Marti1, Daniela Melendez*2,1, Eugene D. Janzen2, Ed Pajor2, Diego Moya1,2, Karen S. Schwartzkopf-Genswein1, 1Agriculture and Agri-Food Canada, Lethbridge, AB, Canada, 2University of Calgary, Faculty of Veterinary Medicine, Calgary, AB, Canada.

Three experiments were conducted to evaluate the effects of band and surgical castration on behavioral and physiological indicators of pain in beef calves at 3 different ages (36 calves/age group): newborn (Exp. 1, 4 ± 1.15 d of age, 43 ± 1.13 kg BW); 2 mo of age (Exp. 2, 63 ± 2.35 d of age, 92 ± 1.75 kg BW); or 4 mo of age (Exp. 3, 125 ± 4.65 d of age, 160 ± 3.36 kg BW). In each experiment calves were randomly assigned to sham (CT), band (BA) or surgical (SU) castration. Exp. 1, 2 and 3 ended when the testicles of banded calves had sloughed off (68, 49, and 42 d, respectively). Animal BW and rectal temperature were recorded weekly over the experimental period. Salivary cortisol, scrotal area temperature using infrared thermography, visual evaluation of swelling (5-point scale), and gait stride length was collected on d 1 and immediately before castration, and weekly thereafter until the end of the study. Hair samples were collected 1 d before and 28 d after castration, and at the end of the study for cortisol concentration. Standing and lying behavior was recorded over a 28-d period immediately after castration. At 4 mo of age, salivary cortisol concentration, scrotal area temperature, and stride length were greater (P ≤ 0.05) in BA compared with CT calves, and lying time was lower (P ≤ 0.001) in SU than CT calves. At 2 and 4 mo, hair cortisol tended to be greater (P ≤ 0.07) in BA and SU compared with CT calves. The maximum degree of swelling (P < 0.05) caused by BA and SU was 1.5 at age 0; 3 and 3.5, respectively, at 2 mo; and 4.5 and 4, respectively, at 4 mo. At 2 and 4 mo of age swelling was observed between d 7 and 14 in SU, and between d 21and 28 in BA. Newborn calves had maximum swelling between d 35 and d 42 in BA and between d 14 and d 21 for SU. Overall, band castration resulted in more chronic indicators of pain than surgical and sham methods. However, as calves got older, indicators of pain increased sequentially in band castrated calves.

Key Words: chronic pain, castration, beef calves