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New Protocols available for treating pain in livestock 07 Nov Western Producer ... We know surgical procedures cause discomfort, but the problem is we have no reliable way to quantify pain in food-producing animals. We assume they feel pain like we do, but we still don't know if something hurts a little or a lot. There has also been little guidance in using painkillers in these animals, at least until recently. Meredyth Jones, a veterinarian at Kansas State University, studied the common procedures performed on animals and created protocols to alleviate pain. The protocols, which she presented at the CanWest Veterinary Conference in Banff, Alta, earlier this year, are intended to be used by veterinarians and producers. Dehorning is necessary for animal welfare, safety and carcass quality. Commonly, a local anesthetic with lidocaine is used to provide pain relief. Unfortunately, this only lasts for about two hours after the procedure. Giving a sedative such as xylazine (Rompun) to the calf stretches the lidocaine effect to about three hours. By using bupivicaine, a different local anesthetic, producers can double the benefit to about four hours. Another way to provide pain relief for dehorning is by injecting a painkiller. A non-steroidal anti-inflammatory such as ketoprofen significantly prolongs pain relief. Jones suggests that an ideal protocol for dehorning calves would be a cornual nerve block with lidocaine and an injection of ketoprofen, both given before the procedure. In goats, two nerves must be blocked. For docking lamb tails, heat docking seems to produce the least pain response. If rubber rings are used, a ring block should be used by injecting a local anesthetic, preferably bupivicaine, around the tail base. Using a Burdizzo past the rubber ring reduces the pain associated with death of the end of the tail. Castration, another common surgery, should be performed as early as possible for welfare and management reasons. Beef Quality Assurance publications recommend it be done before 120 days of age or at a weight of less than 500 pounds. However, every castration method causes pain. Injecting a local anesthetic - local or epidural- has no lasting benefit. It only helps for the first few hours yet the pain continues for days. Local anesthetic is more effective if combined with ketoprofen. The least painful procedure, based on measuring cortisol responses, is Burdizzo castration. Dystocia (difficult calving) has always been a challenge for pain control because interpreting pain during parturition is difficult. Producers have to look at behaviour for clues on the degree of pain an animal is experiencing. For example, heifers can be dangerous to handle because of pain and pressure of the calf in the pelvis. Lidocaine epidurals are commonly used in dystocia, but they only anesthetize the back part of the birth canal. They do not block the front end of the vagina or the cervix, which is where the calf puts most of the pressure. This is why they fail to eliminate straining or behaviour associated with pain. Giving a cow in dystocia an intravenous injection of butorphanol significantly reduces pain and it provides sedation as well. Sedatives such as acepromazine, do not provide pain relief and should not be used alone. If a calf is dead, xylazine can provide sedation and analgesia. These guidelines can be considered a beginning in livestock pain control. For common procedures such as dehorning, tail docking, castration and dystocia, we still don't know precisely which method of pain control is the best. More research is needed. What we do know is that painkillers are far more effective if given before the procedures so that they are working when the effect from the local anesthetic wears off. Its much easier to prevent pain than to treat it. Jeff Grognet, DVM, BSc (Agr) |
