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What are the animal welfare issues with pig farming?

In Australia, pigs that are raised for meat may be housed in several types of farming systems including; indoor intensive systems, semi-indoor extensive (outdoor bred) systems and outdoor free-range systems [1]. RSPCA Australia considers there to be serious welfare problems particularly associated with the use of indoor intensive housing systems for pigs. Pig producers use indoor systems for a number of reasons, including climate control, ease of cleaning, use of labour-saving equipment, protection from predators and control of the animals. However, these systems can have serious welfare issues for pigs due to factors such as barren environments with lack of enrichment, sow and boar confinement, restricted sow feeding and routine painful husbandry procedures (ear notching, teeth clipping and tail docking).

Barren environments and lack of enrichment

Barren environments, such as those in intensive systems, provide minimal opportunities for pigs to fulfil natural exploratory and foraging behaviours that they are highly motivated to perform. The inability to perform these behaviours can negatively affect pigs on both a behavioural and physiological level compromising their welfare. The lack of stimulation in barren housing systems with lack of enrichment not only prevents pigs from performing motivated behaviours, but also leads to boredom and frustration. This can lead to frustration being directed towards other pigs through aggressive behaviour (nosing and biting) or the development of stereotypies. Stereotypies are abnormal repetitive behaviours that can occur in response to stress. Some examples of these behaviours include stereotypic licking, bar-biting or sham-chewing [2]. Pigs in barren environments have also been shown to have higher salivary cortisol (stress hormone) levels than pigs in more enriched environments, indicating that pigs in barren environment may be chronically stressed [3].

Sow stalls and farrowing crates

Both sow stalls and farrowing crates involve the confinement of pigs in metal-barred crates, to the extent that pigs are only able to stand up and lay down but are unable to turn or walk around. When confined they have no opportunity to socialise with other pigs or engage in highly motivated behaviours such as exploratory behaviours or nesting behaviour in pregnant sows. As a result, pigs suffer from stress and frustration when they are confined which can lead to the development of stereotypies and unresolved aggression. In addition to the negative behavioural effects of confinement, pigs, when physically confined, can suffer with reduced bone strength, impaired mobility and reduced cardiovascular fitness. The confinement of pregnant sows during farrowing has also been suggested to be associated with an increased number of stillbirths and aggressive behaviour towards piglets [4]. To learn more about the welfare issues with sow stalls and farrowing crates click here.

The Australian pig industry has committed to voluntarily phasing out sow stalls. Majority of sows are now housed in groups except for the 5 days after mating where they are confined to mating stalls, and the 7 days before farrowing (birthing) where they are placed in farrowing crates until their piglets are weaned. Where sow stalls are still in place, regulation currently requires that they cannot be used for more than 6 weeks during gestation (pregnancy) [1, 5].

Boar stalls

A boar stall is like a sow stall but for boars (adult male pigs). It is a metal-barred pen slightly larger than a sow stall at just 2.4m long and 70cm wide. Like sow stalls, boar stalls only allow enough room for the boar to stand up but he is unable to turn or walk around. Boars are only taken out from these stalls for mating (semen collection) or they may occasionally receive a short walk during the week. Boars in these stalls suffer the same negative welfare effects as confined sows including stress and frustration from confinement, development of stereotypies and impaired mobility. Unfortunately, the Australian pig industry has made no commitment yet to phase out the use of boar stalls in pig farming.

Restricted feeding of sows

The feed intake of breeding sows is commonly restricted to improve productivity and manage mobility issues of confined sows. Sows are naturally motivated to spend a large amount of time during the day foraging and eating. When the opportunity for foraging and time spent eating is greatly reduced such as in intensive farming systems where feed is provided in the form of a pelleted ration, sows spend their remaining time in barren environments with minimal enrichment and unable to perform motivated behaviours. These factors commonly result in sows experiencing hunger and frustration leading to increased aggression, feeding competition between sows, and the risk of developing oral stereotypies (licking, bar-biting, sham-chewing or vacuum-chewing) [2, 6].

Piglet husbandry procedures

In the first few days of life, piglets may undergo several painful husbandry procedures such as ear notching, teeth clipping and tail docking. These painful procedures are routinely performed on piglets without anaesthesia or pain relief. Following these procedures, piglets show obvious signs of pain and distress such as squealing, chomping, clamping their tails between their hind legs, tail wagging and head shaking [7]. To read more about the welfare issues with piglet husbandry procedures click here.

Male piglets may also be castrated when they are young to reduce the risk of aggressive behaviour and undesirable meat characteristics (boar taint). Physical castration when used is usually performed without anaesthesia or pain relief, resulting in significant pain and distress for the piglet. Alternative methods such as immunological castration currently provide a more humane option than physical castration. If piglets are not castrated they are then usually sent for slaughter before they reach sexual maturity.

What is RSPCA’s position on these animal welfare issues?

RSPCA Australia believes that in all farming systems, animals must be provided with freedom of movement and the ability to satisfy their behavioural, social, and physiological preferences and needs. Pregnant sows must be able to exhibit nesting behaviour and all pigs must be able to root, forage and explore. Under the RSPCA Approved Farming Scheme Standard – Pigs, pigs must have bedding and enrichment, and sow stalls, farrowing crates and aversive piglet husbandry procedures are not permitted. Visit the RSPCA Approved Farming Scheme website for more information.

References

[1] Australian Pork: Our Farming Systems (2020).

[2] Hemsworth P (2018) Key determinants of pig welfare: implications of animal management and housing design on livestock welfare. Animal Production Science, 58:1375-1386.

[3] Van de Weerd H (2009) A review of environmental enrichment for pigs housed in intensive housing systems. Applied Animal Behaviour, 116:1-20.

[4] Pedersen LJ (2018) Advances in pig welfare – overview of commercial pig production systems and their main welfare challenges. Herd and Flock Welfare, Ch1 pp3-25.

[5] Primary Industries Standing Committee (2008) Model Code of Practice for the Welfare of Animals: Pigs 3rd Edition. PISC Report 92.

[6] Meunier-Salaün M, Edwards S, Robert S (2001) Effect of dietary fibre on the behaviour and health of the restricted sow. Animal Feed Science and Technology, 90:53-69.

[7] AVMA (2014) Literature review on the welfare implications of teeth clipping, tail docking and permanent identification of piglets.

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Updated on February 6, 2020
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https://kb.rspca.org.au/knowledge-base/what-are-the-animal-welfare-issues-with-pig-farming/

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