Photoperiodism in Pigs Studies on timing of male puberty and melatonin

Andersson, H. 2000. Photoperiodism in pigs. Studies on timing of male puberty and melatonin. Doctoral thesis ISSN 1401-6257, ISBN 91-576-5901-X. The routine castration of male piglets, which is performed in many countries to avoid boar taint in meat, is a cause for great concern in terms of animal welfare. Castrates also have reduced feed efficiency and more fat than do entire males. More of the ingested energy therefore goes to fat tissue than to muscle tissue. The European wild boar is a seasonal short-day breeder and although domestic pigs breed all year round there are indications that they remain responsive to photoperiod. Since boar taint is closely associated with male sexual maturation, the use of artificial light regimens to delay puberty could be a non-invasive method of reducing boar taint in entire males. Therefore, a series of experiments were performed in order to study photoperiodism in young pigs. In two experiments, matched winter-born siblings of crossbred males were allocated after weaning to either one of two light-sealed rooms with high-intensit