Tail biting in pigs: from measurement to genetic solutions for limiting the phenomenon

Abstract

The determinism of tail biting is multifactorial and complex. The general preventive measure is tail docking of piglets shortly after birth. In recent years, a number of recommendations have been issued to limit tail biting and, consequently, tail docking. However, pigs sharing the same environment show widely varying responses to this biting phenomenon. To make progress, it is necessary to deepen our understanding of the factors specific to each individual. This review looks at the genetic and biological factors - body condition, sensitivity to stress, health and microbiota - that interact with the environment to influence the expression of tail-biting. All these factors interact with the genetic predisposition of each animal to bite or have its tail bitten. Progress is expected in the measurement of animal behaviour, working on the biting-victim-neutral typology and the characterisation of their physical and social environment to reduce tail biting. The genetic solution has not been sufficiently exploited to reduce tail biting. The acquisition of continuous individual data at group level and in large populations over several generations is imperative to be able to assess the genetic effects linked to social interactions between pigs. Analytical models that take into account several internal factors at the same time, their evolution over time, and the composition of the group of individuals are now available. Their use should make it possible to improve the welfare of pigs reared in groups.