| Twenty-four steers (avg. wt. = 300.6 +/- 7.6 kg) were randomly assigned to treatments: 1% Tasco meal (TM) vs. no Tasco meal (NT) and thermoneutral (TN) vs. heat load (HL) conditions. The steers were placed in one of four environmental chambers, maintained initially at TN (19°C), with three steers in each room assigned to TM vs. NT. Prior to the study, steers were ruminally cannulated (n = 8) and telemetric transmitters (n = 24) installed in the peritoneal cavity. For 7 d, steers were acclimated to chambers at TN and remained at TN through period 1. Prior to 0730 h, steers were fed treatment premixes of ground corn/alfalfa meal + 1% TM or NT. At 0730 h, steers were fed a cottonseed hulls/cracked corn based diet (12.6% CP; 30.8% ADF; 1.47 Mcal/kg) ad libitum. During periods 2, 3, and 4, two chambers were maintained at TN and two increased in ambient temperature (HL).;The same 24 Angus crossbred steers with an average weight of 374.0 +/- 25.2 kg were randomly assigned to endophyte-infected (E+) tall fescue or endophyte-free (E-) tall fescue pastures. (Abstract shortened by UMI.). |
