114 Monitoring the impact of shade and housing on physiological response in finishing beef cattle during the summer months in the Southeastern United States
A study was conducted to evaluate the effect of heat stress on blood gas parameters of beef steers finished with or without shade in the Southeastern United States. Thirty two steers (BW 453kg 4 kg) were assigned to one of four treatment groups including: inside with fans (CWF) inside no fans (CNF) outside with shade (SHADE) and outside without shade (OUT) All animals were placed into their treatment on d 10 and were given 10 days to acclimate. Animals were fed individually and served as the experimental unit. Animals were weighed and arterial blood was collected on d 10, 0, and 50. Data were analyzed in a completely randomized designed utilizing a one way ANOVA. Initial (d 10) pCO2 values were similar for all treatments (P >0.05) On d0, covered treatments (SHADE, CWF, and CNF) pCO2 values were greater than d 10 (P< 0.01) OUT values did not differ from d 10 to d0 (P 0.95) The change in pCO2 values between d 10 to d0 values were similar for covered groups (P >0.14) and greater than OUT (P 0.02) On d50 all treatment pCO2 values returned to baseline values (P 0.50) and the change in pCO2 from d0 to d50 was greater for covered groups than the OUT group (P 0.04) Initial d 10 pO2 values were similar for all treatments (P >0.05) On d0, covered treatments (SHADE, CWF, and CNF) pO2 values were less than d 10 (P 0.01) OUT values did not differ from d 10 to d0 (P 0.75) pCO2 values between d 10 to d0 were similar across all groups (P 0.38) On d50 SHADE and CNF pO2 values were less than base line (P 0.02) d50 pO2 values for OUT and CWF returned to baseline values (P >0.20) The change in O2 from d0 to d50 was similar across all groups (P 0.84) These results suggest that there is a physiological difference between beef steers fed with cover versus beef steers outside.