172 Effects of Anesthetic and Analgesic Administration at Castration on the Dry Matter and Water Intake, Growth, Feed Efficiency, and Carcass Characteristics of Beef Steers

Abstract

Abstract The objective of this study was to determine the effects of anesthetic and analgesic administration at castration on the dry matter and water intake, growth, feed efficiency, and carcass characteristics of beef steers. Angus (n = 14) and Simmental x Angus (n = 12) bulls (200 to 278 days of age) were randomly assigned to 2 treatments by breed. Control (CON) bulls were castrated by elastration with no pain management. Pain managed (PM) bulls were castrated by elastration, but also received an anesthetic (lidocaine + 10% sodium bicarbonate; 15 to 20 mL) injection and an oral analgesic (meloxicam; 0.992 mg per kg BW). Initial BW = 325.4 ± 36.9 kg and 299.3 ± 48.2 kg for CON and PM bulls, respectively. Steers were provided with ad libitum access to feed and water using an Insentec RIC system (Hokofarm, Marknesse, Netherlands). Beginning 2 weeks after castration, steers received 2 diets containing increasing energy concentrations at weekly intervals until reaching a finishing diet. Steers were implanted 28 d after castration. Dry matter intake (DMI), diet water intake (DWI), liquid water intake (LWI), and total water intake (TWI) were collected from d -7 to d 195. Depression scores were determined at 6, 18, and 30 h after castration. Body weights were collected on d -7, d 0, d 7, d 14, d 21, d 28, and d 195. Camera carcass data and USDA Yield and Quality Grades were collected at slaughter. Data were analyzed using the PROC MIXED procedure of SAS and significance was declared at P < 0.05. Dry matter intake, water intake, and BW were analyzed by periods beginning 1 week before castration (d -7 to d -1). Periods 2, 3, and 4 were the weeks following castration (d 0 to d 6, d 7 to d 13, and d 14 to d 20, respectively). Period 5 was from d 21 to d 195 and overall was from d 0 to d 195. Dry matter intake, DWI, LWI and TWI were unaffected by treatment. Average daily gain (P = 0.0178) and G:F (P = 0.0130) were influenced by treatment x period interactions. Pain managed steers gained faster (ADG: 1.26 vs 0.48 kg/d; P = 0.0069) and more efficiently (G:F: 0.148 vs 0.051; P = 0.0032) than CON cattle in the week following castration. Depression scores, carcass characteristics, overall ADG, and overall feed and water intake were not different. Pain management at time of castration improves ADG and G:F in the short term; however, the effects are not different over the duration of the feeding period. Further research is needed to determine the best method of castration pain management for beef cattle.