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Lidocaine shows promise in mitigating castration pain

Two ongoing projects highlight the potential of using this anaesthetic during processing

Producers may have another option to offset castration pain in calves in the future, thanks to work underway in Western Canada.

Early results from a University of Saskatchewan study suggest using lidocaine in addition to meloxicam during castration may control pain better than meloxicam alone. Dr. Diego Moya, assistant professor at the Western College of Veterinary Medicine (WCVM), is leading this study at the university’s Livestock and Forage Centre of Excellence (LFCE). This research began after Moya and Dr. John Campbell, WCVM professor, discussed the possibility of using lidocaine in a manner that’s more practical for producers.

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Anaesthetics haven’t been widely used as a pain control method at castration due to being seen as less practical.

“Typically they suggest that you should wait half an hour for the lidocaine, in this case, to be fully effective, and that means that the animal has to go two times through the chute to get the castration done,” says Moya.

However, when lidocaine is used for other painful procedures such as dehorning, the wait time after its application is typically shorter than five minutes.

“We thought if we could provide something faster than that — if we give lidocaine and we only wait 90 seconds or pretty much immediately after application we can castrate the animals — that would make that approach more practical and could be potentially more used by the industry.”

Although meloxicam is a pain mitigation drug of choice for many, research led by Dr. Karen Schwartzkopf-Genswein, senior research scientist with Agriculture and Agri-Food Canada, shows this non-steroidal anti-inflammatory drug (NSAID) doesn’t prevent all signs of pain 100 per cent of the time. Moya believes its effectiveness may be increased by combining the use of an NSAID with an anaesthetic such as lidocaine.

This pilot study, conducted last spring at the LFCE, took a simple approach with as little handling of the calves as possible. Moya conducted the trial with the help of summer student Amanda Loeffen and WCVM assistant professor Dr. Nathan Erickson. Forty two-month-old calves were split into two groups, the first of which received just meloxicam. The second was given both meloxicam and lidocaine. Meloxicam was administered subcutaneously in the neck, while lidocaine was given as a ring block of 10 injections of one ml each around the scrotum.

After treatment and castration, the calves were brought to a pen with their dams, where they were observed for an hour. The pairs were then moved back to pasture in an effort to do “something fairly similar to what happens in the industry, rather than trying to collect a lot of samples from the calves, which could be masking the actual effects of the drug,” says Moya. The calves were brought in after seven and 14 days to assess inflammation and collect hair and blood samples.

More research is needed, but early results are promising for the use of lidocaine to control pain during processing.
photo: Diego Moya

Behavioural assessment immediately after castration suggests the lidocaine provided increased pain relief.

“We saw that the number of tail flicks, which is something that is indicative of discomfort and pain, was reduced with lidocaine compared to the other group,” he says. Researchers also saw some changes in the standing and lying behaviour, with the lidocaine group lying down for a longer time, he adds.

They also observed the calves’ movement when they were sent to pasture.

“We observed the distance between the mother and the calf and also how long it took them to reach the pasture,” he says. “We found some changes in their mobility, suggesting that with the lidocaine they tend to move faster and closer to their mom compared to the meloxicam group.”

The results from the blood samples were inconclusive, as the calves were vaccinated at the time of castration, which seemed to interfere with the immune cells results. Hair samples are currently being evaluated for cortisol levels to indicate the calves’ level of stress.

Although the trial was small, results indicate that lidocaine may reduce pain effectively even when administered shortly before castration, Moya explains.

The next step is to conduct a larger trial that may explore other treatment options.

“Maybe use another NSAID or use a different protocol to optimize the effects of lidocaine, but for now we’re really happy with this early result,” says Moya.

There are limitations, Moya notes, with implementing this protocol. For example, lidocaine requires a veterinary prescription.

“But we are still moving forward and trying to reduce the pain, the stress and improving the welfare of the animals that we produce for our food,” he says. “If it shows (to be) really effective, I think it will be really practical as it can be done right before castration, so that will optimize the use of time by the ranchers.”

One step for castration and pain control

Lidocaine’s pain mitigation potential is also being explored with the development of an analgesic elastrator band.

Chinook Contract Research is in the process of creating elastrator bands that release topical lidocaine into the skin, combining castration and pain control in one step. This project, conducted in partnership with Alberta Beef Producers (ABP) and Alberta Veterinary Laboratories Ltd., is geared towards introducing a practical pain mitigation solution while castrating older calves.

The ABP membership “was very keen on having a pain mitigation treatment, particularly on larger animals,” says Nick Allan, president of Chinook Contract Research.

The 2018 updates to the Beef Cattle Code of Practice specify that pain mitigation must be used when castrating bulls six months of age and older.

“A lot of the producers and stakeholder groups were concerned about not having a reasonable answer for this.”

Initial funding for this project came from a grant ABP received through the Canadian Advancing Agriculture Program. Later, the project received additional funding from the province of Alberta through the Strategic Research and Development Program.

Chinook Contract Research works in both animal and human health. “When we do human health work, we do a lot of work around anti-infective agents,” says Allan.

Much of this has to do with medical devices to be implanted or imbedded in the body, which require antimicrobials to be released from the device to prevent bacteria growth.

The company’s animal health work is in partnership with Dr. Merle Olson of Alberta Veterinary Laboratories, and many of their developments relate to pain mitigation. The idea for these bands came from applying the technology they already use in human health care products.

“We thought, ‘Wouldn’t it be great if when you put that band on, it just released an anaesthetic?’”

Upon first glance, these bands look exactly like those already available — the small green bands used shortly after calving, and the larger Callicrate bands used on older calves.

“We wanted a practical solution for producers,” says Allan. “They already have the tools in their shop; they wouldn’t need to get anything additional.”

They chose lidocaine for its success as a topical anaesthetic and because it has no withdrawal period. The bands are soaked in a solvent of lidocaine and other ingredients, including skin permeation enhancer, allowing the anaesthetic to seep from the band into the tissue.

As part of the early field testing, the company assessed indicators of pain. Areas assessed included behaviour, such as kicking, tail flicks and time spent laying down versus standing, heart rate and average daily gain over the trial period. Biopsy samples and electro-cutaneous stimulation were used to detect the presence and amount of anaesthesia in the tissue.

Preliminary results show that when the effective concentration of lidocaine is released into the tissue, it is measurable within 30 minutes and still detectable in the tissue seven days post-castration. The company has been in discussions with Schwartzkopf-Genswein and Moya to conduct field trials in Saskatchewan.

Due to the use of lidocaine in the band, the product will have a best-before date on its packaging, and they’re aiming for a two-year shelf life. Allan’s team is in the process of shelf-life testing, which includes an accelerated age test and real-time testing.

This testing is required to register the product with Health Canada’s veterinary drug directorate. The company met with Health Canada earlier this year to move toward getting this product registered as a veterinary product and making label claims. Further testing will be conducted through field trials in Alberta and Saskatchewan. They aim to prove that the bands allow for the lidocaine to be present in the tissue for greater than 21 days and function in all weather conditions.

Allan believes this product will be attractive to those who may be hesitant about adding an extra step when castrating calves, and sees great value in pain-mitigation efforts.

“It’s an easier-to-administer, potentially long-term pain solution for banding, and this was an industry collaboration throughout the process,” he says. “The final product will be useful for producers, practical and cost-effective as well.”

About the author

Field editor

Piper Whelan

Piper Whelan is a field editor with Canadian Cattlemen. She grew up on a purebred, Maine-Anjou ranch near Irricana, Alta., and previously wrote for Top Stock, Western Horse Review, and various beef breed publications.

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