Nerve Block and Meloxicam Injection to Stop Castration Pain20 February 2013
CANADA - Research suggests that beef calves of all ages experience stress when they are handled or when management practices are applied to them which might cause pain, writes Barry Potter, Agriculture Development Advisor, Ontario Ministry of Agriculture and Food.
The recently released Canadian Code of Practice for Beef Cattle contains strong recommendations for producers to use pain blocks, such as anaesthesia, in dehorning animals over 4 months of age or castrating animals over 9 months of age.
These ages represent a compromise between what is achievable on farm versus the amount of pain an animal suffers. Can we do something to reduce pain in our animals? Is it worth it from a management perspective? Is it the right thing to do?
Let's consider the impact of alleviating pain at castration time. Some people say the impact of castration is so quick that the animal gets over it without any loss of weight. However, calves given a local anaesthetic prior to castration have been shown to weight 35 lbs. more at the end of the trial than calves castrated without any pain alleviation.
Often times these production impacts are hard to measure. But new methods of measuring the neurological impact on calves under stress from dehorning or castration show that we can reduce the pain animals feel from these invasive procedures.
Recent research at Iowa State examined the impact of aspirin on reduction of cortisol, a measure of stress in calves. Calves were split into groups, either uncastrated, untreated and castrated, or treated and castrated. In the trial, calves which did not receive aspirin ended up having higher levels of cortisol.
At a recent Dairy Animal Welfare conference at Guelph, Hans Coetzee,Iowa State University, discussed the use of non-steroidal anti-inflammatory drugs (NSAID) used to reduce pain in dehorning calves. He presented research to indicate the impact of the use of these drugs.
Heinrich et al. (2009) demonstrated that 0.5 mg/ kg meloxicam intramuscular (IM) combined with a corneal nerve block reduced serum cortisol response for 6 hours in 6-12 wk. old calves, compared with calves receiving only local anesthesia prior to cautery dehorning. Furthermore, calves receiving meloxicam had lower heart rates and respiratory rates than placebo treated control calves over 24 hours post-dehorning.
Stewart et al. (2009) found that meloxicam administered intravenously (IV) at 0.5 mg/kg mitigated the onset of pain responses associated with hot-iron dehorning in 5 week old calves compared with administration of a corneal nerve block alone, as measured by heart rate variability and eye temperature.
These findings indicate that administration of meloxicam at 0.5 mg/kg IV or IM decreases physiological responses that may be linked to pain and distress associated with cautery dehorning in preweaning calves.
Meloxicam is an injectable product (Metacam) approvedfor use in calves in Canada. Its labeldirections are quite specific: "As an aid in improving appetite and weight gains when administered at the onset of diarrhoea, in combination with oral rehydration therapy, in calves over one week of age.
For relief of pain following de-budding of horn buds in calves less than 3 months of age." So if we can dehorn prior to 3 months of age, Metacam can be useful in reducing pain in calves.
Pain block to reduce immediate pain from dehorning is possible. Work with your veterinarian to learn how to properly block the nerves going to the area around the horn. There is a valley or soft spot on the side of the calf's head between the eyes and the horn.
By slowly inserting a needle here and fanning the pain block medication into this area, nerve pain can be blocked to the horn area. Calves can be dehorned with much less stress than without any pain block. Regardless of their age, calves will benefit from the use of pain medication for invasive procedures.
Using a pain block, and a pain medication can help lower cortisol or stress levels in calves. The benefits are many fold for the producer: calves are easier to handle when they are not feeling pain, will have reduced sickness and a shorter recovery time afterwards, and increased weight gain as compared to unmedicated animals.
The Code of Practice recommends using them for dehorning and castrating when animals are a certain age. The research shows a benefit to the animal at any age. Work with your veterinarian to develop a program that works for you and your animals.
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