What to do with cull sows?
Around one-third to half of the sow population gets replaced, meaning that millions of sows are going for slaughter every year. Reasons may include low performance, lameness, illness, injuries or undesired behaviour. Often, cull sows are in a poor condition when they are sent to slaughter. Pig welfare expert Dr Irene Camerlink therefore asks the following question: at what point is it better to euthanise the sow on-farm rather than to put her on a truck?
It is unknown to many farmers what happens to a cull sow after she has been put on the truck. Same as other livestock farmers, we may think that she will arrive to the slaughterhouse the same day. However, the transport of cull sows is often not straightforward and can include various detours to load other pigs, stops at collection points, and rest stops in between if needed according to the law. In a US study from 2019, 2.5% of sows travelled 5 times further than the actual distance from farm to slaughterhouse. This makes the transport for already weak sows even more challenging.
Fit for transport?
According to laws in most countries, pigs must be physically fit for transportation. With cull sows this may often be on the edge. Lame sows must be able to bear weight on all 4 legs to qualify for transport, but what about slightly less severe lameness? Some injuries or illnesses might seem fine if the journey would be only to a slaughterhouse an hour away. But the reality is that she may be on the road the whole day in a too hot truck, particularly when the vehicle is stationary. Given sows’ higher metabolic rate, especially when highly productive, they will suffer from heat stress much quicker. Keep this in mind when selling lactating sows on a summer’s day.
Do not transport sows who are unable to walk, in the last 10% of her pregnancy, have farrowed within the last week, or have a uterine prolapse
Balancing between financial and ethical choices
Of course, the financial consequences cannot be overlooked. Euthanising a cull sow on-farm will be better for her welfare, but means only costs and no income. On-farm slaughter would be perfect for animal welfare but the financial gains depend strongly on the market options. Also, on-farm slaughter is insufficiently developed to be accessible to all. Keeping the sows a bit longer to gain strength (and weight) also has costs and often requires regrouping of sows and thus aggression and potential injury. An economic study showed that this is only profitable when feeding inexpensive feed and low labour input, with the greatest efficiency in the first 14 days.
Some guidance on decisions
What to do, when sending weak sows on a potentially long and strenuous journey? Do not send sows who are unable to walk, in the last 10% of her pregnancy, have farrowed within the last week, or have a uterine prolapse. In other cases, imagine how the sow’s condition may be when being for at least several hours in a wobbling truck while fighting. Research has shown that the condition of cull sows deteriorates, in particular the gait and lesions. In case she may be more fit for transport within a reasonable time without needing medication, and there is a suitable space available to let her gain strength, then this may a middle way for animal welfare and farm economics. However, it remains a difficult choice when considering the costs to the animal and the costs to the farm.
