A number of times over the years I have been asked the question “do cattle feel pain the same way we do?” To answer the question, it’s important to understand a little bit about pain physiology.
When a pain stimulus is administered to an animal (for example, you pinch the claw on the hind leg of a calf), it activates pain and pressure receptors in the tissue. The receptors send a stimulus through the nerves to the spine. At the level of the spine there is often a reflex activated that makes the calf withdraw its foot rapidly.
The stimulus continues to travel up the spine to the lower part of the brain; at this point the pain stimulus activates a fight or flight (stress) response. The blood pressure will rise and the heart rate will change.
The stimulus continues to the cerebral cortex where it is perceived as pain. Once the pain is perceived the calf will typically display behaviour to avoid the pain stimulus; it may struggle, and they often vocalize. All of this physiology and some of the associated behaviours are very similar to what we would see in humans, dogs, horses and many other animals.
I think anyone who works with cattle knows that the perception and response to acute pain is not that different from what we see in humans.
The challenge with cattle comes when we try to assess or quantify post-surgical or chronic pain.
Pain in humans is a very personalized experience, we all perceive pain differently and respond to it differently but untreated pain can have adverse effects including depression, increased stress response, and catabolism (increased breakdown of fat and muscle).
In people we rely very heavily on responses to questions in order to assess the degree of pain. The doctor may ask you to grade your pain on a scale of 1-10, you may be asked about the quality of the pain; is it a “burning” sensation, is it a “crushing” sensation. Does the pain radiate to other areas of the body, what behaviours reduce the pain.
Once the doctor assesses these responses, they can prescribe an appropriate pain medication and assess the response to treatment; has the pain diminished or gone away completely. Unfortunately, all of these assessments rely on the individual being able to respond to questions.
Assessment of pain in veterinary medicine can be a real challenge, as we cannot talk with our patients; in general we must rely on behaviour to assess pain. We have developed some very good techniques to assess pain in dogs as they frequently demonstrate behaviours associated with pain and we can group these behaviours into a table that will allow us to score or rate the pain and determine if we need to administer pain medication to treat the pain.
One of the major challenges with cattle is that they do not express many overt pain behaviours and the behaviours that they do express are very subtle. This is common to many prey species, such as deer, cattle and bison. It is probably an evolutionary response as predators will key into these pain behaviours when hunting herd animals. It is in their best interest not to show behavioural signs of pain.
Over the past few years I have been fortunate to have the opportunity to collaborate with Dr. Karen Swartzkopf-Genswein and colleagues at the Agriculture and Agri-Food Canada Lethbridge Research Centre. They have been doing some great work to determine how to assess and treat the pain resulting from surgical and band castration in cattle.
During one of my trips to Lethbridge, I was heading back to the research centre with my colleague Dr. Eugene Janzen. As we were passing one of the pens he suddenly slammed on the brakes of the truck and pointed out the window at the bulls in the pen. He said, “Look at that!” I was not sure what he was pointing to until I suddenly realized that even from a distance we could pick out all of the bulls that had been banded that morning.
The pen was a mixture of banded and unbanded bulls, all the banded ones had assumed a classic stance that we often refer to as the “sawhorse stance.” The animals looked stiff with their hind legs thrust back and had a rigid appearance. Many of these animals were walking around or eating but they were displaying the stance that we typically see with hardware disease, twisted guts and any other conditions that we associate with abdominal pain.
This experience really made me realize that if you take the time to look, and know what to look for, you can often see the subtle behaviours that are associated with pain in cattle. Some other behaviours associated with pain in calves include such things as head shaking, foot stomping and ear twitching. We can look at the frequency of these behaviours in a research setting, but they can be challenging to use when you are trying assess pain in a clinical setting.
We currently have a lot of research tools to help us quantify pain and response to treatment following surgery in cattle. We can look at their stride length, the amount of time they spend lying or standing, feed and water consumption and weight gain. We can measure stress hormones and other markers in the blood associated with pain but we still often return to behaviour in a clinical and research setting.
I think over the years that I have studied the assessment and treatment of pain in cattle I have come to the conclusion that cattle feel and respond to acute pain in a very similar way that we do. I also believe that cattle feel chronic or post-surgical pain the same way that we do, but their behavioural response to chronic pain is very different to ours.
In answer to the question. Cattle feel pain the same way that we do, but their expression of pain is much more stoic.
Dr. Nigel Caulkett DVM, MVetSc is a diplomate of the American College of Veterinary Anesthesia and Analgesia and professor and department head of veterinary clinical and diagnostic science at the University of Calgary.