1 Awardee Talk: Investigation of Pain and Analgesic Strategies in Cattle Undergoing Painful Husbandry Procedures and Disease Conditions

Abstract

Abstract Negative public perception of routine husbandry practices such as dehorning and castration is growing, increasing the need for the development of practices to relieve pain and suffering in livestock. The objective was to quantify pain associated with induced bacterial pneumonia, hot-iron dehorning, surgical castration, and hot-iron branding, and to investigate analgesic effectiveness. Calves were experimentally inoculated with Mannheimia haemolytica, cautery dehorned, surgically castrated, or hot-iron branded. Outcome variables were collected at baseline and following husbandry procedures and included serum cortisol; infrared thermography (IRT); mechanical nociceptive threshold (MNT); substance P; kinematic gait analysis; a visual analog scale (VAS); chute defense and behavior scoring; clinical illness score; computerized lung score; average activity and rumination; prostaglandin E2 metabolite (PGEM); plasma serum amyloid A and rectal temperature. Reduced activity levels, decreased force on calves’ right front limb, and increased VAS scores all support that bacterial pneumonia in cattle is painful. Differences in right front force were observed in calves challenged with M. haemolytica and treated with flunixin transdermal and those given a placebo, indicating that flunixin transdermal may attenuate specific pain biomarkers in cattle with respiratory disease. Pain from cautery dehorning and surgical castration can last up to 120 h post-dehorning indicated by changes in IRT, MNT, PGEM and gait analysis. Administration of bupivacaine liposome suspension as a local anesthetic block at the time of dehorning and castration was as effective at controlling pain as a multi-modal approach of lidocaine and meloxicam. Changes in IRT, MNT, lying time, step count, visual analog scale score and wound scoring all support that hot-iron branding cattle is painful. Oral meloxicam administration reduced IRT differences from the branding and control site and reduced lying bouts. Breed and sex effects were observed across a wide range of biomarkers. The need for long-acting analgesic options for cattle that demonstrate pain alleviation across multiple biomarkers is apparent and would be beneficial to alleviating pain and suffering.