Tail and ear biting lesions in pigs: an epidemiological study
Tail and ear biting lesions have a negative effect both on the animal welfare status of pigs (Sus scrofus) and the economical revenue of the pig farm. Tail biting behaviour is an unpredictable, abnormal behaviour that is thought to have a multifactorial origin. On-farm factors
influencing tail biting have been described, but the real triggers are poorly understood. Much of the research into tail biting has been done on a small scale within a well-controlled environment and small sample sizes. This well-controlled environment is not always representative of the contemporary
commercial conditions. Therefore, an observational epidemiological approach at farm level was adopted to gain a better insight into the factors influencing the occurrence of tail and ear biting lesions. Tail and ear biting lesions were observed at pen level three times a year on sixty farms
across Belgium. A questionnaire was conducted to build a multifactorial model indicating different risk factors concerning the lesions scored. The temperature and the number of feeding places per animal in the nursery, the percentage of floor space covered with slats in the farrowing unit,
the feed type in the growing unit and the overall hygiene policy were the most important indicators for the appearance of tail and ear biting lesions during fattening. The leave-one-out cross validation of the model demonstrated an intraclass correlation coefficient of 0.55 between the predicted
model outcomes and the observed data. This epidemiological study provides important potential risk factors in relation to the incidence of tail and ear biting lesions. However, experimental and/or longitudinal studies have to confirm that the correlations found in this work are causal factors.