Have we dropped the ball on castration?

It eases the management of large farm animals, reduces the chances of unwanted mating, and improves carcase quality. In the UK, we use three main methods: rubber ring, bloodless (eg burdizzo), and surgical removal.

Although UK farmers often swear by ring castration for its speed and ease, its necessity is being called into question. Other European countries and overseas competitors have either abandoned or changed the practice. Uncastrated animals grow faster and avoid the risks of haemorrhage and infection.

Not only this, but with the prospect of new trade deals, an increasing consumer awareness and interest into animal welfare, and the ever-evolving presence of technology in farming, we may soon have to find better ways to skin a cat, or ring a lamb.

So why have our continental cousins taken a different approach? The shift is likely due to consumer demand for high welfare products, as well as an increasing understanding of how pain affects productivity.

The young animal is born with fully developed nerves. This may surprise some, as legislation recommends castration within a week of birth. This legislation arose as the Protection of Animals (Anaesthetics) Act of 1954, because at the time we believed younger animals were less sensitive to pain. This stance is embarrassingly outdated.

Unfortunately, since then we have found the opposite: painful procedures conducted on younger animals can actually reduce their stress and pain thresholds later in life. However, there are practical reasons for castrating younger animals – handling, ease of management, and wound size to name a few. The question is, do these pros outweigh the cons on a practical and economic level?

To answer this question we need to work out how much pain is really caused by current methods, and what effect this has on productivity of the animal.

It would be easy to believe rings immediately cut off blood supply and nerve function as soon as they’re applied, but this is not the case. The nerves and vessels of the testicles run through the very centre of the neck of the scrotum, so it can take hours for them to be fully crushed by the ring.

However, this isn’t the only problem. The application of the elastrator ring causes reduced blood flow to the area. This causes cells to die. When they die, they try to alert the body to danger by sending pain signals.

These signals can still be sent up the nerves for a while, because the nerves are one of the last structures to die. Another major source of pain arises from something called a neuroma – essentially a messed up nerve trying to heal itself after injury.

Our fourth problem is that inflammation (causing chronic pain) can continue for up to six weeks after ringing – which is arguably quite a long time to feel like you’ve been hit in the testes.

Problem five is through something called sensitisation or '“wind-up', which occurs after a painful stimulus. The pathway to the brain gets so much traffic from the site of trauma that it becomes hypersensitive to any stimulus, even just a light touch.

This means an animal may be affected by pain even after the testicles are removed, because the rest of the pathway is still intact.

Ok, so we know castration should hurt. But how do we know young animals actually feel pain? Pain is measured in animals in several ways –behaviours we know are associated with it (extension of limbs, stamping, stiffening, looking ‘sleepy’, licking, among others), the levels of stress hormone in the blood, and brain activity.

It’s worth noting some behaviours are not that obvious. For example, a sleepy looking ringed lamb may appear to be dozing, but it’s stress hormone levels could be a hundred times greater than the norm.

Prey animals hiding pain (rather than not experiencing it) makes sense in terms of evolution. Pain is what tells us to stop walking on that sore foot, so that it has a chance to heal. If an animal couldn’t feel pain, it would injure itself a lot, and end up too dead to pass on its genes.

If it got really good at hiding pain, it would be less likely to be picked on by predators, but still be able to avoid further damage, and still pass on its genes. That is the evolutionary basis for why sheep are so good at looking ‘fine’, then suddenly dying for no obvious reason.

Pain is obviously not ideal, but we can’t just pay the vet to knock out every animal for every painful procedure. However, we must consider the economic impacts of pain.

Theoretically, it’s likely to have a negative effect on productivity. However, this has not been reliably shown in the example of castration. What has been observed in some studies is that mortality is higher in animals castrated without pain relief, but this is difficult to prove.

However, economic gain can be sought by entering a ‘high welfare’ market, and to not do so could be considered a loss.

There are some promising new pieces of kit which may be conservative (and cheap) enough to be integrated into our routines. One of which, Numnuts, is being phased into use in Australia.

It’s essentially an optimised elastrator, only with a gun attachment which quickly injects local anaesthetic into the site. The device and treatment runs a maximum cost of around 50p per lamb on a small (500 ewe) flock, or less for bigger units.

The disadvantages of using this could be outweighed by the economic benefits of pioneering a new welfare friendly market. The main drawback of Numnuts, other than cost, is it’s a bit fiddly to do one-handed, and is better suited to the cradle systems used in Australia and NZ.

There are also injectable proteins, such as Improvac, Bopriva, and Vaxtrate. These use the animal’s own immune system to deliver the effects of castration.

They have been shown to cause less pain than traditional methods, and – unlike ring and surgical castration – do not cause an open wound, which reduces the subsequent risks of infection, stress and mortality.

A cheaper option is to combine burdizzo and elastrator rings. By doing this, you get the benefit of crushing the nerves all in one go (and hence fewer pain impulses reach the brain afterwards) and the rubber ring handles the actual removal of the testicles.

This may be the quickest and easiest options, and could make a significant difference to the individual animal even if it’s still painful. However, this method only reduces pain responses if conducted under a week of age.

Short scrotum castration, where the testicles are pushed back inside the body and only the scrotum is removed with a ring, is less painful, and significantly reduces the chances of successful mating- but does not eliminate them.

Overall, whether or not we can be convinced that using new methods can make a visible or immediate difference to our economic outputs, our attitude to castration is currently much more lax than other EU countries, Australia and New Zealand.

If Britain wants to truly boast the best welfare practices in the world, we will need to re-evaluate our standing amongst our potential trade partners on this matter. Trying some new tech can’t be worse than being outdone by the French.