Behavioural alterations in piglets after surgical castration: Effects of analgesia and anaesthesia.

The present study aimed to use behavioural measures to assess pain induced by surgical castration of piglets, and evaluate the efficacy of pain-relief medications. In total, 143 male piglets from 29 sows were used. The treatments included: 1) non-castration (NC; n = 28), 2) castration without medication (SC; n = 29), 3) castration with meloxicam injection 0.4 mg/kg i.m. (ME; n = 28), 4) castration with 0.5 ml of 2% lidocaine in each testicle (LA; n = 29), and 5) castration with general inhalation anaesthesia using isoflurane (1.5%) and meloxicam injection (GA; n = 29). Behaviour was monitored continuously for a ten minute period one hour prior to castration (-1 h), as well as immediately (0 h), one hour (1 h), and two hours (2 h) after castration. Behaviour was also monitored twice (08:00 and 20:00) during the following day. Compared to -1 h, castration induced changes in several behavioural measures in SC piglets at 0 h, suggesting that castration was painful. Furthermore, inactive standing or sitting, tail wagging and aggressive behaviour differed between SC and NC piglets at 0 h. ME and LA piglets spent less time standing or sitting inactively, and LA and GA piglets showed more tail wagging than SC piglets at 0 h (P < 0.05 for all). No other behavioural measures differed among the various groups of castrated piglets. In conclusion, the results indicate that surgical castration is indeed painful. However, the efficacy of various pain-relief protocols in piglets shortly after castration was not verified.

Strategic use of anti-GnRH vaccine allowing selection of breeding boars without adverse effects on reproductive or production performances.

Boar stations raise only entire male pigs for selection as reproductive boars, but the majority of them will fail the selection process, ending at slaughter with a high risk of boar tainted meat. The aim of this study was to investigate whether a single dose of Improvac given to 16-week old boars had a negative effect on their subsequent sperm numbers and motility in 16 artificial insemination boars. We also aimed to generate more knowledge on incidence of boar taint at slaughter among Finnish pigs, compare production performances as average daily gain, feed conversion ratio, and carcass and meat quality (lean meat percentage, back fat, pH, color, androstenone, and skatole) of immunocastrated boars (n = 248) with those of entire boars (n = 268). Moreover, we aimed also to explore whether a fat biopsy taken at 16 weeks of age could already reveal the presence of boar taint compounds and be predictive of boar taint development at slaughter age. We found that 32% of entire boars (Figen Landrace, Figen Large White, and their crossbreed) slaughtered at an age of 25 weeks presented levels of androstenone and/or skatole above the threshold for boar taint in their meat. These boars (control) had higher androstenone and skatole levels in the back fat samples at slaughter (0.77 ± 0.55 and 0.09 ± 0.06 µg/g, respectively, mean ± standard deviation) than those in the immuno group (0.20 ± 0.25 and 0.06 ± 0.03 µg/g, respectively, P < 0.001). A single dose of anti-GnRH vaccine, given at 16 weeks of age, did not affect future sperm numbers and motility of boars selected for artificial insemination. We found no difference in the levels of testosterone, anti-GnRH antibodies titers, testicle morphology, and sperm numbers and motility between the boars vaccinated once, at 16 weeks of age, with anti-GnRH vaccine and the control boars (no vaccination). There were no differences in average daily gain, feed conversion ratio, lean meat percentage, and back fat between the immunocastrated boars and entire boars. Meat from immunocastrated boars had a higher pH and better color than meat from entire boars (P < 0.001), suggesting slightly improved meat quality.