There is a range of pig rearing systems, from organic to intensive large-scale production. In recent years, there has been an intensification of pork production and the establishment of specialised farms. Due to the specific nature of pig breeding and rearing, the welfare of these animals in large-scale farms should be under special scrutiny.
Ensuring adequate pig welfare is determined by several factors, including the housing system, environmental management, nutrition and the provision of adequate care. Serious problems can arise in any system if one or more of these elements are missing.
In terms of pig welfare, their physiological and behavioural requirements should be considered first and foremost. In the case of piglets and piglets, important factors include:
- time spent with the mother and contact with peers,
- a soft, stimulus-rich substrate to satisfy the cognitive instinct,
- space in which a high level of juvenile life activity can manifest itself.
- key factors in sow welfare are:
- maintenance in groups, which corresponds to the characteristics of the species,
- being on soft ground allowing instincts to manifest,
- extension of the feeding time, which is related to the quantitative and qualitative composition of the diet, the presence of an adequate amount of fibre in the ration,
- availability of material useful for nesting and environmental enrichment.
There are, however, undesirable behaviours – aggression or strep. One of these is cannibalism. This behaviour manifests itself by biting tails and ears. Biting of the flanks and vulva also occurs. Tail-biting is not just a manifestation of pig aggression, but results from the redirection of the animals’ natural behaviour to other stimuli. In the natural environment, pigs spend more than 60% of their time searching for food and exploring the environment (rutting, sniffing, etc.). Despite genetic changes over the years, their needs have remained constant. Therefore, it is important that they are influenced by the right stimuli and, more specifically, are provided with environmental enrichment.
Factors associated with the incidence of organ biting in pigs include:
- poor environment/no enrichment,
- lack of material to enable rutting in the pen (with slatted floors). Pigs have an irresistible need to explore their surroundings and forage (sniffing, biting and chewing),
- inadequate ventilation in pigsties,
- frequent temperature changes in the pig room, inadequate lighting, high ammonia levels. Pigs need a stable environment that provides them with optimum temperature and humidity levels, no draughts and adequate lighting,
- too high a density of animals in the pen,
- poor health and disorders of the digestive system (pain, as a cause of abnormal behaviour). Good general health is the best way to avoid tail-biting. Pigs in poor condition are stressed and aggression is exacerbated,
- an improperly balanced feed ration. Pigs need feed with the right consistency and an adequate intake of minerals, fibre and essential amino acids. They also need sufficient fresh and good quality water,
- competition, especially for food. Pigs prefer to forage, eat and rest together. They should be given sufficient space and the opportunity to satisfy their behavioural needs when taking food (minimising competition),
- stocking density in the pen and its cleanliness. Pigs prefer to reserve particular parts of the pen for different behaviours (resting, eating, defecating). A dirty environment and excessive crowding is a cause of stress,
- individual factors (age, genetics).
EU Directive 2008/120/EC sets out minimum welfare standards for pigs. It stipulates, among other things, that group-housed pigs must be protected from fights by using plenty of bedding or, if possible, by introducing other materials, suitable for exploration and providing occupation. Subsequently, Commission Recommendation (EU) 2016/336 of 8 March 2016 sets out specific criteria for enrichment materials for pigs.
Surrounding enrichment materials should:
- be safe and have the following characteristics:
- be edible – so that the pigs can eat them or sniff them – and, if possible, they should also have nutritional value,
- be chewable – so that the pigs can chew them,
- be suitable for examination – so that pigs can examine them,
- be manipulable – so that pigs can change their position, appearance or structure.
- be taught in such a way that:
- arouse sustained interest, i.e. they should stimulate exploratory behaviour in pigs and be regularly replaced and supplemented,
- enabled oral manipulation,
- were available in sufficient quantities,
- were clean and hygienic.
These criteria make it possible to divide materials that enrich the pig environment into:
- optimum materials – materials possessing all the characteristics listed in points 1 and 2, and therefore suitable for use on their own,
- sub-optimal materials – materials possessing most of the characteristics listed in points 1 and 2 and therefore suitable for use in combination with other materials,
- materials of marginal interest – materials that divert the pigs’ attention, which should not be considered to meet the pigs’ basic needs; optimal or sub-optimal materials should also be provided for these materials.
Symptoms indicating that the enrichment material is of inadequate quality or the enrichments are insufficient:
- bitten tails and ears,
- skin damage,
- loss of interest in enrichment materials over time,
- chewing of pen equipment or other pigs instead of enrichment materials,
- riting or burying in faeces,
- competition or struggle for enrichment materials,
- poking the nose in the stomach.
The routine clipping of pigs’ tails is prohibited. The procedure may only be carried out if tail damage is occurring on the farm and if all possible causes of tail damage have been addressed.