The farrowing crate is a small metal cage in which pregnant sows are imprisoned for weeks on end, usually from a week before giving birth until their piglets are weaned three to four weeks later. The metal frame of the crate is just centimetres bigger than the sow’s body and severely restricts her movements. She is completely unable to turn around, can scarcely take a step forward or backward and frequently rubs against the bars when standing up and lying down. Beside her cage is a “creep” area - usually around 50-100cm x 2m in size – for her piglets. The flooring is hard concrete and some form of heating, either mats or more commonly heatlamps, is used as a substitute for the warmth of their mother’s body. The piglets are free to reach the sow’s teats to suckle but she is prevented from moving close to them and cleaning them by the bars of the cage.
When not in the crate, sows used for breeding are kept separate from those used for meat, most commonly in concrete pens. Sows have a pregnancy lasting around four months and are usually reimpregnated within a week of their piglets being weaned, approximately a month after they were born. This means they are forced into the farrowing crate for 28-35 days every five months until, usually at around five years old, they are no longer commercially productive and are sent for slaughter. The crate is used for around 80% of the 512,000 breeding sows in Britain (DEFRA, 2004a).
The constraint of the farrowing crate prevents the sow from fulfilling any of her natural maternal instincts. Studies of wild or semi-wild pigs show that sows actually become more active before giving birth, often walking many kilometres to find a suitable nest site (Cronin et al, 1995; Biensen et al, 1996). They would naturally seek out a site in a covered area which is isolated from the rest of the herd (Jarvis et al,1997). They then prepare a nest of twigs or leaves before giving birth. The standard practice of confining sows in the farrowing crate a week before they give birth not only restrains them at a time of increased restlessness but also denies them the privacy they desire by forcing them into close proximity with other sows. Building a nest has been described as “the single, strongest instinct for a sow” (Per Jensen, quoted on Bowman website) and research indicates a very strong desire for sows to obtain nesting materials (Arey, 1992). Even when they have nothing but a hard floor, sows still attempt to build a nest, pawing at the floor, nuzzling the bars and attempting to turn around. Although new legislation will compel farmers to provide some straw for sows in the crate, for a confined sow in a metal cage on hard flooring inside a building, the nesting instinct will still be completely frustrated.
While confined in the crate, the sow is unable to move toward her piglets when she wants to but is also prevented from moving away from them when she wants to. This can lead to aggression towards piglets, with 1 in 8 piglets fatally mauled by their mothers (New Scientist, 2000). This is a very rare event in the wild.
The farrowing crate itself can cause the sow painful sores and also pain and fatigue due to immobility. Studies of hormone levels indicate raised levels of stress in confined sows (Cronin, 1996; Jarvis et al, 1997; Lawrence et al, 1994; Lynch et al, website). Confined sows are also more aggressive than sows who have not been confined when returned to pens with other pigs (DEFRA, 2002).
The crate is supposedly used to prevent sows from accidentally crushing their piglets. In fact, the danger of crushing is a direct consequence of factory farming techniques. In the wild, nests protect piglets from crushing because they are pliable, providing some cushioning for piglets if lain on; because piglets may simply fall through or out of nests; and because the sow roots around before lying down giving the piglets warning that she is about to do so. The crate offers none of these forms of protection. Factory farming also depends on minimising staff costs and that means that most births are unsupervised. Brazil had half the pre-weaning mortality of the USA in the early 1990s because of higher staff ratios (Holyoake et al, 1995) and other South American countries have achieved mortality rates as low as 3% (Guise & Mayland, 1998).
Alternative farrowing systems - such as Solari, Volkenroder and Werribbee pens - have achieved broadly comparable weaning rates to conventional crates in experimental conditions (ibid; Arnott, 2001; Cronin et al, 1999; Far Eastern Agriculture) while outdoor herds have lower mortality rates than indoor, according to MLC research (Far Eastern Agriculture, 1996). Selection of sows – both by breed and as individuals – for “good” mothering is also effective in reducing piglet mortality from crushing and other causes in organic and conventional farming (Brown, personal communication; DEFRA, 2004b).
Piglet mortality increases with larger litter sizes (Jarvis, 2002) and pigs today have been bred to produce litters of up to fifteen piglets, where naturally around 8 would be normal. Large litter sizes increase competition and lead to malnourishment for weaker piglets. Weaker piglets are at greater risk of being crushed (Arey et al, 1992). Recent evidence suggests that dietary changes alone may have a significant impact on crushing death rates for piglets (Allison, 2003). Farmers are also likely to blame crushing for deaths which are actually caused by malnourishment (Vallaincourt, quoted in Holyoake et al, 1995). In fact, piglets in farrowing crates appear more likely to die as a result of savaging by the sow, starvation/chilling and splay leg (Cronin et al, 1996).
The crate also confines piglets. In the wild, three week-old piglets would usually be found 20-30m from the sow (Pasille & Robert, 1989). In the crate they are also unable to mix with other litters and this makes them more prone to fighting when they are weaned (DEFRA 2002). Piglets reared in open systems demonstrate improved weight-gain after weaning and exhibit fewer skin lesions, another sign of fighting (Malkin et al, website; DEFRA, 2002) .
Natural weaning age for pigs is between 12 and 15 weeks and the process occurs gradually over the weeks before final weaning. Abrupt weaning, whether at 21 or 28 days, is more than piglets’ immature digestive systems can cope with (Van Heugten, website), often leading to scours - diarrhoea - and failure to thrive. As a result, piglets require medication and, in intensive conditions, end up on a daily regime of drugs. Weaning in this abrupt manner is also, clearly, a psychological trauma to both mother and piglets.
The problem the farrowing crate is designed to address - piglet crushing - is a direct result of factory farming techniques. While pigs are reared intensively that problem will persist. Even the introduction of non-crate systems in indoor farming is resisted for commercial reasons. In the words of one expert on pig welfare:
“. . . Producers are wary of change because of the costs involved in providing efficient and humane farrowing accommodation” (IJ Lean, in Ewbank et al, Management and Welfare of Farm Animals, 4th Ed, 1999)
The farrowing crate is designed to increase productivity of piglets. It is not used to preserve their welfare but to preserve the meat they will produce. Farmers - and the Government - accept its severe adverse consequencesfor both sow and piglet welfare because it is, at present, the most cost-effective system overall. From a welfare point of view, it is indefensible.
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