No abstract

Injection anaesthesia with a combination of ketamine and azaperone (K/A) is discussed as a painless alternative to commonly used non-anaesthetized castration. To protect anaesthetized piglets from being crushed, they have to be separated from the sow for 3 h following castration. The aim of this study was to test if this separation and the different treatments would affect short-term behaviour after castration (3 to 6 h after castration) as well as weight gain. Piglets were 5 to 7 days old. Treatment Group 1 received a combination of anaesthesia and analgesia (n 5 29, ketamine: 25 mg/kg BW; azaperone: 2 mg/kg BW; meloxicam: 0.4 mg/kg BW), Group 2 received only analgesia (n 5 24) and Group 3 received no medication (n 5 29). Behaviour and suckling order were compared for a 3 h period the day before castration and after castration. A significantly higher number of teats used by anaesthetized piglets (P 5 0.004) suggests a decrease in suckling order stability. There were significant treatment effects between all three groups in the time spent at the sow's teat, with an increase in Group 2 (169%), decrease in Group 1 (228%), whereas the control Group 3 (12%) almost remained unchanged. The anaesthetized piglets showed an increase in the time spent active away from the sow after castration of almost 200% (Groups 2 and 3: ,50%, P , 0.001). However, no significant treatment effect was seen for weight gain. The results suggest that analgesia has an effect on behaviour, perhaps due to less post-castration pain. This advantage is not apparent for animals receiving additional anaesthesia, probably because of impaired coordination. Although the behavioural changes did not affect weight gain significantly, a decrease in suckling order stability indicates a certain degree of stress due to fighting over teat positions as a consequence of separation. Thus, postcastration behaviour must be taken into account when evaluating alternative castration methods.Keywords: anaesthesia, analgesia, teat order, piglet castration, animal welfare ImplicationsInjection anaesthesia (ketamine/azaperone) and analgesia (meloxicam) during the castration of pigs is considered as a welfare friendly alternative to conventional castration without any anaesthesia and post-castration pain treatment. Our study suggests that this combination of injection anaesthesia and analgesia in particular impairs the short-term suckling behaviour and teat order of piglets. In contrast, analgesia treatment alone resulted in a higher suckling order stability with no changes to a lower (posterior) teat position and increased time spent at the teat after being reunited with the sow. The results suggest that analgesia treatment alone has an effect on post-castration behaviour, perhaps due to less post-castration pain.

Awareness of factors (positive and negative) which influence motivation of participation in a clinical trial is useful to provide strategies for successful enrollment of patients.

Previous studies have shown that the analysis of high frequency stress calls in pigs can serve as a reliable tool in welfare research. Our study focuses on the classification of three different classes of piglet vocalisation: grunting, squealing and screaming. In a castration experiment (Experiment 1), 3,285 vocalisations from 42 piglets were analysed for 21 different vocal characteristics. A first discriminant function for the three vocal types was derived from recordings made under laboratory-like conditions. A second discriminant function was derived from non-calibrated measurements of the relative sound energy content. These two classifications revealed 86.7% identical assignments of vocalisations to the three vocal types. The second classification allowed for vocalisation analyses of animals under on-farm recording conditions. This technique was validated during an open-field test (Experiment 2) with piglets housed in two different farrowing systems (11,089 vocalisations, 22 piglets). The proportion of screaming sounds was lower for piglets from a group-farrowing (GF) system than for those from a single-farrowing (SF) system. Sound properties showed differences between as well as within the two experiments for all three vocal types. Vocalisations from SF and GF piglets differed significantly in the duration, energy, and relative maximum levels. We conclude that vocal-type analysis can not only help to identify vocalisation indicative of pain during castration, but also vocal behaviour changes indicating separation stress during the open-field test. Therefore, classification of vocal types can add valuable information to studies that use pig vocalisation for the assessment of welfare.