Effects of oral meloxicam on physiological and behavioral outcomes of weaned calves following band castration.

Abstract

Castration detrimentally affects weaned calves, and painful procedures in production animals are a public concern. The objective of this study was to determine the effects of castration (by banding) with or without administration of meloxicam (Mel), a non-steroidal anti-inflammatory drug in weaned beef calves. Forty-eight (62 d post-weaning) beef calves [8.2 ± 0.1 (mean ± SE) mo old; 319 ± 10 kg BW] were blocked by age and body weight and randomly assigned to 1 of 3 treatments (n = 16 calves per treatment): 1) intact bulls (BULL), 2) castration by banding (BAN), or 3) castration by banding with orally-administered Mel (3 mg per kg BW on d 0 and 14; BAN + M). Within each treatment group, calves were randomly assigned to 8 pens (2 calves per treatment within each pen). Body weight and plasma haptoglobin and fibrinogen concentrations were determined on 0, 3, 7, 14, and 28 d after treatment administration. Rectal temperature was recorded at 5-min intervals for the first 14 d by dataloggers. Behaviors [mean lying time (h/d), mean lying bouts (n/d), and steps (n/d)] were recorded at 1-min intervals for 27 d by dataloggers. Ethogram data was recorded on 8 d for two hours with collection times of every 10 min. Behaviors recorded from the ethogram included eating, ruminating, not ruminating, drinking, location within the pen, and body position (standing or lying down). Data were tested for effects of treatment, day, pen, and treatment by day interaction using mixed models accounting for repeated measures. BULL gained more (0.69 ± 0.12 kg/d; P < 0.05) than BAN (0.15 ± 0.11 kg/d) or BAN + M (0.14 ± 0.11 kg/d) over 28 d. There was an effect of treatment (P < 0.001) and treatment by time interaction (P < 0.001) on mean rectal temperature during the 14 d after treatment administration. Over 14 d, BAN + M had the greatest mean rectal temperature (39.47 ± 0.006 °C), BAN had the second greatest temperature (39.42 ± 0.006 °C), and BULL had the lowest temperature (39.41 ± 0.005 °C). BULL increased time lying (P < 0.05) and decrease steps (P < 0.05), compared to BAN, Days 2, 3, 16, and 17, and compared to BAN and BAN + M Days 18 and 19 post-castration. Mel administration had an insignificant effect on pen-level behaviors recorded with the ethogram. Decreased weight gain indicates that castration by banding during the post-weaning period was painful regardless of attempts and pain abatement with Mel. While benefits of Mel were not evident from changes in growth or inflammatory response, behavior and rectal temperature were affected by Mel administration.