Pain management in farm animals is a significant animal welfare concern, with more than 120 million pigs and 35 million calves raised in the US each year. However, there are no drugs labeled to relieve pain resulting from dehorning and castration. Kansas State University has assembled a multidisciplinary team of clinical pharmacologists, livestock production specialists, and animal behavior and welfare specialists to address this need.
Developing a tool kit for assessing pain in farm animals
Food and Drug Administration Guidance 123 proposes the use of validated methods of pain assessment in the target species to support analgesic drug approvals. With the support of grants funded by the USDA National Institute of Food and Agriculture (USDA-NIFA), our group has validated the use of pressure-sensitive mats to measure pain-associated changes in gait. This technology was used to support the approval of the first food animal analgesic drug to manage foot rot pain in cattle. We have pioneered the use of infrared thermography to quantify changes in skin temperature from pain-associated peripheral vasoconstriction in cattle and piglets. These outcomes are measured concurrently with novel behavior and facial grimace scoring systems that we have described in calves, piglets, and goats.
These projects have culminated in a multi-institutional collaboration with the American Association of Swine Veterinarians, FDA, partner universities, and industry, supported by USDA-NIFA, to identify and validate end points for use in future clinical trials evaluating drug efficacy to control pain associated with piglet castration. We are also exploring a universal blood test for pain by evaluating circulating transcriptomic biomarkers after painful procedures. Technological advances have resulted in the use of machine learning and precision technology for the analysis and validation of pain biomarkers in our laboratory. This work will improve farm animal welfare by advancing the multidimensional assessment of livestock pain to support future analgesic drug approvals.
Providing on-farm solutions for alleviating pain
In the absence of drugs specifically labeled for alleviating pain after dehorning and castration, extralabel drug use is permitted in accordance with the Animal Medicinal Drug Use Clarification Act (AMDUCA). K-State researchers were the first to demonstrate that oral meloxicam tablets provide safe, long-lasting, and effective analgesia in livestock after a single dose and we reported that meloxicam increases weight gain in calves after dehorning and reduces the incidence of bovine respiratory disease after castration. Our research group was also the first to describe the use of gabapentin for alleviating chronic pain associated with bovine lameness.
Time sequence thermography video recorded during surgical castration in a Holstein calf. Color changes (red to yellow to green) indicate changes in skin temperature associated with peripheral vasoconstriction mediated by catecholamines released in response to surgical pain.
Citation: American Journal of Veterinary Research 84, 9; 10.2460/ajvr.23.07.0153
Current projects are focused on optimizing the transmammary delivery of oral firocoxib from the sow to the piglets to provide a cost-effective, convenient, and needle-free solution to alleviate castration and tail-docking pain at processing. We are engaged in studies to provide dose, route, duration, frequency and withhold period recommendations for analgesics in goats and to explore game-changing strategies, such as an immunocastration vaccine ear implant, to reduce the number of painful on-farm procedures.
Taken together, the animal welfare program at K-State is committed to delivering practical and cost-effective pain management solutions for on-farm use and to validate pain assessment tools that support future analgesic drug approvals.
