One of the challenges in the production of slaughter pigs is tail biting which can result in serious tail damage. Tail biting is painful and a sign of reduced welfare for the pigs, as well as an economical problem for the farmer. Prevention of tail biting is therefore important and in everyone’s best interest.

Yet tail docking is used as the primary preventive measure against tail biting. This is not an optimal solution since tail docking is painful for the pigs. New studies conducted by Department of Animal Science, Aarhus University, show that the risk of tail damage in the slaughter pigpen is reduced to the same level if straw provision and a lowered stocking density are combined, as if the pigs had been tail-docked. The research also shows that other strategies, such as early warning of tail biting, can be necessary to avoid tail damage.

Risk reduction

EU legislation does not allow routine tail docking of pigs and demands that the environment of the pigs is improved according to their needs before resolving to tail docking. This can be done by removing known risk factors of tail biting. Earlier studies have investigated the effect of removing single risk factors but not the risk factors’ relative effect compared to tail docking. Such studies can be especially important to overcome the idea that slaughter pigs cannot be raised without tail docking.

Effect of tail docking, straw and stocking density

The Department of Animal Science, Aarhus University, has completed an investigation where the effect of tail docking, straw provision (150 g/pig/day) and lowered stocking density were compared in relation to the risk of tail damage in slaughter pigpens. The results showed that all three preventive measures lowered the risk of tail damage and that a combination of the measures lowered the risk even further. When the measures were compared, tail docking was the most effective. Although the risk of tail damage was lowered to the same level as with tail docking, if straw provision and lowered stocking density were combined.

The conclusion of the investigation was that it would most likely require a combination of preventive measures to be able to replace tail docking. Thus, prevention of tail biting when raising pigs with intact tails will require an extra effort of the farmer. 

Early warning

The above-mentioned investigation also showed that not even a combination of all three preventive measures could remove the risk of tail damage entirely. This result emphasises that it is worth to investigate other strategies to prevent tail biting. The same investigation, thus, also focused on early warning of tail biting. The purpose of this strategy is to inform the farmer of pens in high risk of future tail damage. This can help the farmer to focus on specific pens with high risk of tail damage in the close future and make it possible for him to initiate actions in these pens based on his own experiences of what works at his herd. With it, the farmer can intervene early and hinder that tail biting develops into tail damage. 

Observation of behavioural changes prior to tail damage

 The investigation focused on behavioural changes in the days leading up to tail damage and found that pigs’ manipulation of hard wooden sticks, activity level and tail posture in pens with tail damage differed from pens without tail damage. However, the changes were not so distinct that the farmer would be able to observe himself in the stable. Thus, the next step in the development of the early warning strategy will be to develop automatic tools to observe these types of behaviour in slaughter pigpens.

Overall, the investigation showed that risk reduction, here represented by straw provision and lowered stocking density, is an effective strategy to prevent tail biting and that a combination of preventive measures is probably required to replace tail docking. However, it is also necessary to look into alternative strategies, such as early warning of tail biting, especially for the production of pigs with intact tails. 

More information

Mona Lilian Vestbjerg Larsen, Department of Animal Science, Aarhus University.

E-mail: mona@anis.au.dk