Indicators of Pre-weaned Calf Respiratory Health in Dairy Industry Welfare Standards

This Capstone Synthesis review paper bridges sickness behavior ethology research in pre-weaned dairy calves to industry-driven quality assurance (QA) and third-party welfare standards. The objective is to identify calf-based behavioral measures of Bovine Respiratory Disease (BRD) from applied ethology and determine the extent to which reliable and specific behavioral indicators of pre-weaned calf BRD are integrated into welfare assessments in the US dairy and calf rearing sectors. The hypothesis is that calf-based and behavioral indicators of respiratory health derived from sickness ethology research will be unevenly and minimally incorporated into both US dairy industry-driven welfare standards as well as third-party auditing welfare standards for pre-weaned dairy calves. The approach used in this paper includes (1) an overview of sickness behavioral indicators of BRD in pre-weaned dairy calves (2) aggregating clinical and pre-weaned calf-based indicators of BRD in respiratory scoring systems (3) comparing outcome-based measures of pre-weaned calf respiratory health in dairy industry quality assurance (QA) programs with those in third-party welfare assessment. Findings indicate that specific and reliable behavioral indicators of pre-weaned calf BRD have been incorporated into respiratory scoring systems, but use of scorers and calf-based measures of respiratory health are not widely applied on-farm in US dairy industry welfare assessment. Improving reliability of respiratory scorers and standardizing training of observers may improve on-farm implementation of these tools and facilitate wider uptake of calf-based measures of respiratory health into existing QA and third party welfare standards. Calf-based indicators specific to respiratory health were not present in any of the welfare standards evaluated, although management-based indicators in some welfare standards recommended sick animal health monitoring and individual calf record-keeping using BRD-related sickness behaviors and respiratory scorers.