EFFECT OF DIFFERENT METHODS OF CASTRATION ON BEHAVIOR AND PLASMA-CORTISOL IN CALVES OF 3 AGES

Calves of six, 21 and 42 days were either handled (controls) or castra ted by Burdizzo, by surgical or by rubber ring techniques and their be haviour and plasma cortisol monitored for three hours after treatment. The rubber ring caused significant increases in active behaviour and abnormal postures for two hours compared with handled or castrated by Burdizzo and surgical techniques, and surgical techniques resulted in a significant increase in abnormal standing, particularly in the first 30 minutes. Abnormal behaviour and posture were recorded less frequen tly in six-day-old calves. The mean cortisol peaks for six-, 21- and 4 2-day-old calves were, respectively, 36, 31 and 23 nmol litre(-1) in t he handled groups; 60, 43 and 48 nmol litre(-1) in the rubber ring gro ups; 77, 50 and 62 nmol litre(-1) in the Burdizzo groups; and 106, 63 and 107 nmol litre(-1) in the surgical groups. The greatest cortisol r esponse occurred in 42-day-old surgically treated calves and the short est response after Burdizzo castration. These responses suggest that i rrespective of age, all methods of castration studied caused acute pai n. Burdizzo castration appeared to produce the least pain, particularl y in younger calves.