By Cassie Yost
In today’s dairy industry, there are management practices that some people may view as cruel or unnecessary. However, it is crucial to remember that farmers have the best interest and well-being of their cows in mind. A farmer’s cattle are his or her livelihood and proper care and treatment are essential for the success of their businesses. Because farming practices come under such scrutiny, it is vital that proper management and procedures are being done to help calm the public’s concern and ensure the welfare of these animals.
One practice that may be a cause for concern is dehorning, or in calves that are under 3 weeks of age, disbudding. Removing the horns of dairy cattle helps to protect the animal itself, the rest of the herd, and also the people that are working with the animals. In the United Sates, farming ranks among the highest for work-related fatal and non-fatal injuries (Dogan and Demirci, 2012). Agriculture has an 8.5 times greater fatality injury rate than all other occupations’ combined injuries (Dogan and Demirci, 2012). Obviously not all of these are cattle-related injuries, but The Center for Disease Control and Prevention (CDC) estimates that about 22 people are killed by cows each year in the United States. Because this is such a dangerous profession, farmers do what they can to minimize risks to themselves. Dehorning is one of these practices. Therefore, because it is a welfare issue, we must focus on the best ways to make calves as comfortable and pain-free as possible during this event.
Scientists have studied the best practices to minimize the stress and pain felt by calves during dehorning. Most of the studies included blood sampling of calves to monitor cortisol levels. Cortisol is a steroid hormone produced by the adrenal gland that is produced when a calf is stressed. Therefore, blood samples were routinely collected and analyzed to monitor stress levels. Also during these studies, calves were monitored for behaviors such as head shaking, ear flicking, head rubbing, tail flicking, and foot stamping. These actions are thought to be some physical indicators that the calf is experiencing pain. Through analysis of the cortisol levels, assessing visual cues, and monitoring feed and water intakes, researchers offer their recommendations for minimizing stress and pain when dehorning.
The most common method of dehorning and disbudding is hot iron cauterization. There are other methods available, however, this is the method that was used in all of the aforementioned studies. One important part of dehorning is to provide a local anesthetic to the calf in order to block the cornual nerve, which supplies sensation to the horn. In 2007, researchers investigated different strengths of the anesthetic lidocaine during dehorning. This study assessed the effectiveness of 5% lidocaine versus 2% lidocaine in providing prolonged pain relief and reducing the stress response in dairy calves during the 72-hour period after dehorning (Doherty et al., 2007). Calves in this study were either given 2% lidocaine, 5% lidocaine, or a saline solution that did not contain an anesthetic. The results of the study showed that the use of the anesthetic, at either 2% or 5%, did not provide any additional pain relief following dehorning. At the time of dehorning, the saline and 2% lidocaine-treated calves displayed the greatest magnitude of cortisol increase as compared to the 5% lidocaine group. Although there were no significant behavioral changes following dehorning, there were noticeable differences at the time of dehorning. The 5% lidocaine treated calves showed less kicking during dehorning, suggesting that these calves were able to maintain a greater level of well-being during the procedure. Overall, this study concluded that the use of an adequate level of anesthesia may provide an overall decrease in the stress response in calves at the actual time of dehorning (Doherty et al., 2007.)
The next phase of dehorning consists of finding an acceptable method of pain management for the calves. Two similar studies published in the Journal of Dairy Science looked into the effects of using meloxicam during the dehorning process. In 2010 researchers compared dehorning calves using meloxicam or a placebo. Meloxicam is a common nonsteroidal anti-inflammatory drug (NSAID) used for pain management. This drug is a favorable choice over others because it has a half-life of approximately 26 hours in cattle, thus providing longer pain relief than others such as ketoprofen and flunixin meglumine that only have a half-life of approximately 6 to 7 hours (Heinrich et al., 2010). This study did not involve blood sampling but did include the nerve block with lidocaine and focused on behaviors believed to be responses to pain. Calves treated with an injection of meloxicam displayed less ear flicking and head shaking following dehorning. These calves were also less active than the control calves during the first 5 hours following the actual event, leading researchers to believe that the reduced pain experience facilitated this resting behavior. This study concluded that meloxicam was effective at reducing pain following dehorning and was able to reduce pain for up to 44 hours with a single injection (Heinrich et al., 2010).
Another study in 2013 went into further research on the timing of meloxicam during dehorning and took into consideration the cortisol levels of the calves given meloxicam. This study was done to assess the effect of oral meloxicam on pain response after dehorning and to determine if oral meloxicam was more effective when given 12 hours prior or at the time of the procedure (Allen et al., 2013). Calves that received meloxicam had significantly lower serum cortisol concentrations compared with the control calves. Although this study did not find any clinically significant differences between when the meloxicam was administered, it did conclude that meloxicam was able to suppress the pain response following dehorning (Allen et al., 2013).
Dehorning is a stressful event for calves. However, as compared to weaning, transportation, and some other typical events on a farm, the effects from dehorning wear off much quicker than other events. In the studies discussed earlier, calves did not suffer any setbacks as far as feed and water intakes were concerned and generally were back to normal behaviors by 72 hours post weaning. When we dehorn calves, it is essential to remember to use an adequate nerve block as well as a long lasting anesthetic in order to minimize the stress and pain to these calves. When done properly, dehorning does not have to be such a dreaded event for calves or for farmers.
Source:psu.edu