PARTNERSHIP: OPTIMIZING DAIRY CATTLE WELFARE AND PRODUCTIVITY IN A THERMALLY CHALLENGING CLIMATE

Overall aimTo understand the variability of the heat stress response and to evaluate a suite of non-invasive metrics, using a combination of body-mounted, video analytic, and productivity tracking technologies, that are representative of an individual that can remain consistently productive during thermally challenging environments.Objective 1: The ethology of heat stressWe will characterize the variability and consistency of early lactation dairy cow behavior and productivity during a variety of heat stress conditions (measured within the barn) using body-mounted technologies (e.g., rumination collar, pedometer), the Lely A4 Robotic Milking System (e.g., milking behavior, milk yield, dead milk time, milk flow speed, fat, protein, lactose, solids non-fat, milk), video analytics (e.g., water use, brush use), and reproductive success (e.g., DIM at first service, first service conception rate).Objective 2: The temperament of heat stressThe autonomic nervous system (ANS) controls anxiety, thermoregulation, and the startle response. We will characterize the behavioral response of cows to a startle test during their dry period. The goal is to assess whether metrics reflective of ANS reactivity (e.g., behavior during the startle test, dead milk time, max milk speed) or activation (e.g., drinking behavior, brush use) would be viable phenotypes for characterizing dairy cow temperament and heat stress responsivity (Figure 2).Objective 3: The genotypes for the phenotype of heat stressObjective 3: The genotypes for the phenotype of heat stressOur inter-disciplinary team will synthesize behavioral, physiological, productivity, genetic, and environmental data to identify novel animal-based indicators of heat stress, evaluate the heritability of these phenotypes, and to characterize automated, non-invasive phenotypes for identifying specific cows that can maintain productivity during thermally challenging conditions.