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How castration method and age affect pain in young calves

Research on the Record with Reynold Bergen

Canada’s Code of Practice for the Care and Handling of Beef Cattle requires that castration be performed by an experienced person who uses proper, clean, well-maintained equipment and accepted techniques. A producer is expected to seek guidance from their veterinarian on the optimum method and timing of castration, as well as the availability and advisability of pain control drugs for castrating beef cattle. Calves must be castrated as young as practically possible, and pain control is required when castrating bulls older than six months of age.

The requirement to use pain control in older calves was based on research demonstrating its effectiveness in feedlot bulls. A lot of information was also available regarding the use of pain drugs in baby dairy calves, but the beef producers and researchers on the code committee felt that the vast differences in genetics, herd dynamics and familiarity with people meant that nursing beef calves may respond differently to castration than individually housed dairy calves that had been weaned at birth. A research project funded by the Beef Science Cluster is helping to determine when pain control is beneficial in beef calves. As a first step, students working with Karen Schwartzkopf-Genswein (AAFC Lethbridge) and Ed Pajor (University of Calgary) examined how age and castration method affect acute and chronic pain in nursing beef calves (Journal of Animal Science 95:4352-4366 and 95:4367-4380).

What they did: Angus-cross bull calves were divided into three groups of 36 head. Groups were either castrated at one week (early April), two months (late May), or four months of age (early August). In each age group, 12 were knife-castrated, 12 were banded, and 12 were not castrated (control) but otherwise handled the same. The one-week group was handled on the ground. A tip table was used for the two-month group, and a hydraulic squeeze was used for the four-month group. Scalpels were used for surgical castration at one week of age. A Newberry knife was used in older calves. Rubber rings were used for band castration in the one-week and two-month calves and a Callicrate bander was used in four-month calves. Acute pain was evaluated using intensive physiological and behavioural pain measurements collected the day before castration, during castration, the hours immediately after and the first seven days after castration. Chronic pain and scrotal swelling and healing were assessed using weekly physiological and behavioural measurements collected over six to nine weeks, and weaning weights were compared.

What they learned: Acute pain in the first week after castration differed between methods. Regardless of age, behavioural responses at the time of castration were strongest for knife-castrated calves, intermediate for banded calves, and lowest for the controls. At two and four months, knife-castrated calves kicked and bawled more than band or control calves. Signs of pain related to tail flicking, lying, standing and walking behaviour were also more evident in surgical than band or control calves in the hours and days after castration at two or four months. Scrotal temperatures were lower in banded than in surgical or control calves at all ages.

Strictly speaking, the effect of castrating at different ages couldn’t be compared statistically, because the calves were castrated in different months, and because handling and castration techniques varied slightly between the age groups. Technicalities aside, only two or three pain indicators were apparent in either castrated group compared to control calves at one week. At two months, nine pain indicators were different in surgically castrated than control calves, while only two indicators were different in banded calves. At four months, 12 pain indicators were significantly higher in surgically castrated than control calves, and five were higher in banded calves.

Chronic pain beyond the first week of castration was not observed in calves castrated at one week or two months of age. Standing and lying behaviour was significantly altered in the six to nine weeks following castration in calves banded at four months of age compared to control or surgically castrated calves.

Scrotal swelling and healing: There was less scrotal swelling and swelling went down sooner in surgically castrated than in band castrated calves at all ages. Scrotums healed at the same time for both methods in the one-week and two-month groups. Surgically castrated calves healed much sooner than banded calves in the four-month group.

Performance: Initial weights at the time of castration were the same within each age group, but weaning weights were significantly lower for knife calves than with banded or control calves at one week (507 vs. 557 lbs.) and four months (518 vs. 535 lbs.) but not at two months of age (507 lbs.).

What it means: Castrate calves as young as practically possible. Banding caused less acute pain than surgical castration banding at two months, but more chronic pain at four months. This group is currently looking at the potential added benefit of providing pain relief drugs when castrating young calves.

The Beef Research Cluster is funded by the Canadian Beef Cattle Check-Off and Agriculture and Agri-Food Canada with additional contributions from provincial beef industry groups and governments to advance research and technology transfer supporting the Canadian beef industry’s vision to be recognized as a preferred supplier of healthy, high-quality beef, cattle and genetics.

About the author

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Dr. Reynold Bergen is the science director of the Beef Cattle Research Council.

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