Veterinary science could learn from the past “30 years of mistakes” with research into human pain, to better treat livestock pain.
- Research shows evidence of pain can be seen in the cells of livestock, just as it can be detected in humans
- The research could make it easier to treat chronic pain in livestock
- Animals experiencing less pain will eat better and survive longer in changing climates
University of Adelaide’s Mark Hutchinson has been researching if pain changes the bodies of livestock animals in similar ways to how it changes humans.
Professor Hutchinson said modern science had found that pain, including chronic pain, could change human cells and that he had found the same could be said for livestock.
“We now know what pain looks like at a cellular molecular level in mice and rats from our research experiments and we know what it looks like in humans,” he said.
“The first step for us has been to ask, ‘Do we see these same signatures in sheep, beef, cattle, and pigs?’ And, yes, we do.”
Professor Hutchinson said the research opens the way to testing new medicines that could control acute and chronic pain in livestock.
He said that preventing chronic pain in livestock would not just make the animals more comfortable but would also improve farmers’ bottom lines.
“The upside is that — if you have animals that are resilient, able to make decisions and not developing chronic pain — those animals will have greater immune protection capacity. They will have the decision-processing ability to eat food when they need it and they’ll have greater emotional capacity.
“All of those point to an animal that is better off under difficult, climate-changing environments, but also one that should be easier to rear and, therefore, literally have more meat on the bone.”
Human experience relevant
According to the federal government, about one in five Australian adults aged 45 years and over had chronic pain in 2016.
Professor Hutchinson said that, while there was no data on how prevalent chronic pain was in livestock, it should be as common as it is in humans, especially since most livestock herds are dominated by female animals.
“If we take what we know from humans, roughly 20 per cent to 40 per cent of the human population, predominantly women, have exaggerated pain,” he said.
“Now, women are 50 per cent [of] the human population, [but] there’s a stark imbalance in the livestock production to a female-dominated herd and mob.
“That means that we would anticipate on the human to sheep and cattle translation, that there would be a profound presence of chronic pain in that [animal] population.”
How pain science has changed
The University of South Australia’s Lorimer Mosely has researched pain in humans and said the understanding of pain had changed significantly in the past few decades.
Professor Mosely said that, rather than pain being generated by injuries, the brain created pain based on the information it received from the body and the context.
“I think that’s the biggest shift is that we now know that pain does not exist until the brain says so,” he said.
“It wasn’t that long ago that that we would think that pain was something that was detected in the tissues of your body — let’s say in your knee — and it would send a pain message up to your brain and your brain would register that.
Professor Mosely said that, in some cases, the brain may not generate a strong pain response to a serious injury if not doing so could help keep the sufferer alive.
“You might be in the paddock, on your own, and you might have sustained a catastrophic injury to your leg, for example, but your brain might say, ‘You need to get back to the back of the house to survive’, so … you don’t experience any pain whatsoever.”
However, Professor Mosely said, the body could also “learn” to experience pain even once an injury had healed, resulting in chronic pain.
“The longer you have pain, the nerves that send messages and the networks in your brain that create this horrible feeling that you have, they get better and better at it, they learn how to produce pain,” he said.
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