According to the EFSA, tail-biting is a major issue in modern pig breeding. The opinion separately looked at the issues of avoidance of tail-docking and the provision of manipulable materials, such as straw, hay, saw dust, paper and woodchips, which meet the needs of the animal.
Datasets were used from 242 farms in five countries – Spain, France, Finland, Netherlands and Sweden – as well as data from 1,574 farms in Finland.
Among the main conclusions were that pigs need manipulable materials to satisfy a range of behavourial needs, which differ dependent on the class of pig. However when these needs are not met, they are at an increased risk of tail-biting – especially in weaners and rearing pigs.
It also deduced that certain materials, while good at meeting these behavourial needs, can also have adverse effects on elements of animal welfare.
The analysis of a large Finnish dataset with undocked pigs showed that the use of straw was associated with reduced tail-biting prevalence relative to the other types of manipulable material (including objects) present on Finnish farms. "No other manipulable material gave consistent reduction in tail-biting across both weaner and rearing pigs compared to the population average," said the AHAW.
The opinion added that analysis of an international dataset using its Welfare Quality protocol suggested that a number of animal resource-based factors could be important risk factors for tail-biting, but a high degree of uncertainty in the model precluded strong conclusions.
Recommendations arising from the work included the need for further research in a number of areas, including further harmonised data collection from across Europe.