Reducing calves’ castration pain drives research


Source: University of Saskatchewan, Jessica Colby

Canada’s national codes of practice for the care and handling of both beef and dairy cattle recommend that male calves be castrated within the first few weeks of life.

“The younger the better,” stresses Dr. John Campbell, a professor and beef cattle veterinarian at the Western College of Veterinary Medicine (WCVM). Campbell has also led previous studies evaluating pain mitigation options for calves.

While most cattle producers will castrate their calves within a few months of birth, current guidelines don’t require the administration of any form of pain mitigation when castrating calves under six months of age.

However, Canada’s cattle industry is searching for an effective and economical way to mitigate the calves’ pain during castration that addresses welfare concerns. The industry’s need is driving a new WCVM study involving Campbell and his colleague Dr. Diego Moya, a specialist in beef cattle behaviour and welfare.

One of the study’s goals is to develop a standardized pain evaluation protocol to help with the development and registration of future pain mitigation tools.

“[We are hoping to] kind of summarize or filter the amount of tests that one researcher has to do in order to evaluate pain, because so far, it’s a little bit all over the place,” says Moya.

The study’s other goal is to evaluate the effects of a new castration tool that includes extended-term delivery of a local anesthesia drug.

The project focuses on testing pain mitigation options in young calves at two different ages: castration at two weeks and castration when the animals are five and a half months old.

“There are two specific ages which are of interest for the industry trying to provide some analgesic (pain relief),” says Moya, this project’s lead investigator. “Up until now, the … only prescribed solution is Metacam, an anti-inflammatory drug.”

Cattle producers have two pain-mitigating drug options for use on calves before castration. They can use a local anesthetic drug such as lidocaine — the same medication used by dentists to reduce pain in their human patients. However, local anesthetics must be given some time before castration — plus they have a limited window of effectiveness.

“The short duration of the lidocaine, along with a difficult administration method, actually doesn’t make it that relevant for the industry to use it, so that’s why they go for the Metacam, which is easier to administer and has a longer-lasting effect in the animal,” says Moya.

Metacam contains meloxicam, a non-steroidal anti-inflammatory drug (NSAID) — the second drug option available for cattle producers. Researchers have developed specific NSAIDs for cattle, and these drugs tend to work better for managing pain associated with castrating since their pain-relieving effects can last anywhere from 36 to 48 hours.

In their study, Moya and Campbell are evaluating the pain mitigation effects of a novel, lidocaine-infused castration band developed by Alberta Veterinary Laboratories in Calgary, Alta.

“We don’t want to run the cattle through the chute every two days to give them more pain control. We’d like to just give them pain control once,” explains Campbell.

By using the band “that has some lidocaine impregnated into it,” Campbell says the technique has potential for providing longer-term pain control.

“[The castration bands are] a good technique, especially in young calves — it’s probably one of the least painful ones. But it still causes some pain, so if this technique would work, it would be a solution to one of the castration techniques where the injectable products don’t work terribly well because they don’t last long enough.”

Producers can use castration bands in younger and older calves. With this method, producers can place a small, tight band around the calf’s testicles to restrict the testicular blood supply. Three to six weeks later, the testis and scrotal tissue slough off.

In addition to testing the new castration band, the researchers will evaluate the calves’ pain after using a regular castration band with either no pain medication or with local injections of lidocaine.

Moya will evaluate several factors that may indicate pain in calves, including how often a calf kicks its belly and how much it swishes its tail.

“Beef cattle in general [are] quite [a] stoic species and some of them are very good at hiding pain just because through evolution, they have been trained to hide any pain or injury so they’re not the target of predators,” says Moya, who will use a series of video cameras to monitor the calves’ reactions to the procedure.

“I think the behaviour is going to be an important component in capturing the individual science of pain and coming up with results on this problem.”

In addition to evaluating behavioural factors that indicate pain, Moya and his team will also evaluate blood samples for signs of tissue damage and inflammation. In terms of stress, they’re looking at cortisol levels in calves’ coat hair samples to measure chronic stress and analyzing saliva samples from the calves to monitor acute stress.

As well, the team will analyze the testicular tissues of calves that receive the new lidocaine-infused band to measure levels of the local anesthetic in their tissue and to ensure that the novel bands are working.

Castration is a necessary procedure that protects the health and welfare of individual cattle and the whole herd, and the industry can’t compromise on that point.

“Once bulls are pubertal (reach sexual maturity), they can be potentially dangerous,” says Campbell. “They can also fight with each other as they get older and can be hard on facilities.”

He adds that in North America, people don’t typically consume bull meat; consumers prefer the quality and texture of meat from steers. As a result, the carcasses of bulls are usually priced lower.

“Castration still has to happen for different safety and meat quality issues — but it has to happen … under the best conditions possible,” says Moya.

Saskatchewan’s Agriculture Development Fund (ADF), SaskMilk and the Beef Cattle Research Council (BCRC) have provided funding for this study, along with an in-kind contribution from Chinook Contract Research and Alberta Veterinary Laboratories.

Jessica Colby of Montmartre, Sask., is a University of Regina journalism student. She worked at the WCVM as a summer research communications intern in 2021.


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