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This paper constitutes a review on the welfare aspects of piglet castration that considers the scientific literature published after 2004. Castrating during the neonatal period (1 to 3 days of age) is clearly painful. In addition, inflammatory processes may take place at the sites of incision, thus adding further pain to the procedure. Surgical castration with general and local anaesthesia, in combination with long-term analgesia, has been shown to reduce pain but the additional handling and injection of the anaesthetic, the effectiveness and limited safety margins have to be thoroughly evaluated. Raising entire males during the whole fattening period or immunocastration of males towards the end of the fattening period are other alternatives with welfare benefits in young pigs compared to current surgical castration, but with some potential welfare drawbacks regarding handling stress and behaviour during fattening. Based on the current knowledge, it can be concluded that sperm sexing and raising entire males after genetic control of boar taint are potentially preferable alternatives to current practices, but need further research, as these methods are not yet available.

Many of the behavioral responses following acute bacterial or viral infection are now considered important for maintaining homeostasis during inflammation. In the present study, we extend this concept to pigs (16 crossbred barrows) by demonstrating that lipopolysaccharide (LPS, .5, 5, or 50 micrograms/kg BW) from Escherichia coli injected i.p. reduces feed intake, decreases activity, and elevates body temperature. To determine whether any of these effects could be mediated via a prostaglandin (PG)-dependent mechanism, a second experiment with 16 crossbred barrows was conducted. Barrows were pretreated with indomethacin (IND, 5 mg/kg BW [a cyclooxygenase inhibitor]), and their behavior and body temperature following a challenge i.p. injection of LPS (5 micrograms/kg BW) were assessed. Pretreatment with IND inhibited the anorexia and inactivity caused by LPS, suggesting that the behavioral effects of LPS are dependent on activation of a PG system. Lipopolysaccharide alone, however, did not elevate body temperature in this case; thus, the involvement of PGs in this response was not determined. Collectively, these data indicate that pigs respond to LPS by reducing feed intake, decreasing activity, and becoming febrile. The ability of IND to inhibit behavioral effects of LPS is consistent with the hypothesis that a PG system is involved in mediating sickness behavior. Perhaps, by altering the activity of cyclooxygenase it is possible to enhance or inhibit the behavioral symptoms of sickness in pigs.

Using a comparative approach, we investigated the ability of dwarf goats and sheep to use direct and indirect information about the location of a food reward in an object-choice task. Subjects had to choose between two cups with only one covering a reward. Before making a choice, subjects received information about the baited (direct information) or non-baited cup (indirect information). Both goats and sheep were able to use direct information (presence of food) in the object choice task. After controlling for local enhancement, we found that goats rather than sheep were able to use indirect information (i.e., the absence of food) to find a reward. The actual test setup could not clarify whether individual goats were able to inferentially reason about the content of the baited cup when only shown the content of the non-baited cup or if they simply avoided the empty cup in that situation. As browsing species, feral and wild goats exhibit highly selective feeding behaviour compared to the rather unselective grazing sheep. The potential influence of this species-specific foraging flexibility of goats and sheep for using direct and indirect information to find a food reward is discussed in relation to a higher aversion to losses in food acquisition in goats compared to sheep.