144 Assessing economic implications of thermal stress of Bos indicus and Bos taurus species during finishing in northern Colorado

Abstract

Abstract The objective of this study was to determine the economic implications of thermal stress on climate adaptive capacity, resiliency, and impact of Bos indicus and Bos taurus finishing steers using common finishing systems. The experimental design was a completely randomized design, with a 2 by 2 factorial arrangement of finishing system (‘natural’ or ‘conventional’) and species of cattle (Bos indicus or Bos taurus). Steers [n = 200; body weight (BW) ~450 kg] were housed in 20 feedlot pens (10 steers/pen) for the first 84 d, where cattle were blocked by initial BW. For the remainder of the 180 d (96 d) finishing period, cattle were moved to four Climate Smart Research Pens (50 steers/pen, 1 pen/ treatment, and species combination). Within each Climate Smart Research Pen, five SmartFeed systems were used to evaluate individual animal feed intake, one GreenFeed emission measurement system was used to evaluate individual animal gas emissions flux of enteric CH4, O2, H2, and CO2, and were equipped for nutrient mass balance of carbon, nitrogen, and phosphorus. Animal BW were collected every 28 d for analysis of average daily gain (ADG) and feed efficiency. Thermal stress behaviors were evaluated by one trained personnel on a subset of 7 steers/treatment via the measurement of respiration rate, open mouth breathing, rumen temperature, number of daily water intake events, lying and standing behavior, and pen surface temperature for the last 96 d of the finishing period. At harvest, carcass characteristics, liver scores, and heart scores were collected. Economic analyses were conducted post-hoc to determine the profitability of each species based on economic implications, tradeoffs, carcass quality and quantity, and time to finish. Selection of cattle for climate adaptive features may involve production tradeoffs (e.g., depressed rate of gain, greater yield risk, lower technical efficiency) and adjustment costs (e.g., re-optimizing feed for a new breed), which affect the adoption of less common breeds into the US cattle supply chain. Adding to the complexity of this evaluation, consumers preferences may not adapt quickly, affecting the prospect of Bos indicus cuts of meat in the market. We also, therefore, explore the supply- and demand-side effects of climate change adaptation through breed selection in the beef industry.