It has become an increasingly widespread practice to administer local anesthesia to calves prior to dehorning to prevent pain. But is that enough? A team of Austrian researchers led by Dr. Marc Drillich with the University of Veterinary Medicine, Vienna, Austria, recently conducted a study to evaluate whether further measures to alleviate pain had an effect on calves. The team's results were reported in the January 2013 Journal of Dairy Science.
Eighty calves of 5 to 9 weeks of age were evaluated in four study groups of 20 calves each. The treatment groups were:
- Local anesthesia (10 mL procaine hydrochloride) plus 2.2 mg flunixin meglumine/kg of bodyweight 20 minutes before hot-iron dehorning and again three hours after dehorning.
- Local anesthesia plus flunixin meglumine before dehorning plus a placebo 3 hours after dehorning.
- Local anesthesia plus a placebo both before and after dehorning.
- No treatment and no dehorning.
Blood samples from all groups were collected 20 minutes before restraint in a headlock before dehorning; two minutes after dehorning; and 30 minutes and 1, 2, 4, 6 and 8 hours after dehorning.
The researchers found significantly higher levels of the stress hormone cortisol at 30 minutes and 2 hours post-dehorning in the double-placebo group compared to the group that received two doses of flunixin meglumine. The group that received one dose of flunixin meglumine also showed higher levels of cortisol than the group that received two doses. Throughout the study, cortisol levels in both groups that received flunixin meglumine were similar to those of calves in the non-dehorned control group, indicating that they incurred very little stress throughout the dehorning process.
Source: Journal of Dairy Science, January 2013, Vol. 96, Issue 1, Pages 132-140, J. Huber, T. Arnholdt, E. Möstl, C.-C. Gelfert, M. Drillich