|Carroll, Jeffery - Jeff carroll|
Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 10/20/2005
Publication Date: 7/9/2006
Citation: Vann, R.C., Randel, R.D., Welsh, Jr., T.H., Willard, S.T., Carroll, J.A., Brown, M.S., Lawrence, T.E. 2006. Influence of breed type and temperament on feedlot growth and carcass characteristics of beef steers [abstract]. Journal of Animal Science. 84:396(Suppl. 1). Abstract #468. Interpretive Summary:
Technical Abstract: Forty steers (Angus, n = 20; Brahman, n = 20) were used to examine the effects of breed type and temperament classification on feedlot growth performance and carcass traits. Steers were weaned, assigned a temperament classification (TEMP; calm or excited), commingled and grazed on rye-ryegrass pastures for 130 d and then shipped from Overton to Canyon, TX (500 miles). At weaning, steers were assigned a pen temperament score (PS; 1 = non-aggressive, to 5 = aggressive), weighed and assigned a chute score [CS; 1 = calm, to 5 = highly agitated), restrained in a squeeze chute, and then released. Time to travel 1.83 m was recorded (exit velocity (EV), m/s). TEMP represented the combined weaning PS and EV measurements. Steers were assigned to pens at the feedlot based on mean TEMP: calm pen means for Angus were 2.3 and 2.3 (n = 2), and for Brahman were 1.4 and 1.4 (n = 2; SEM 0.4); excited pen means for Angus were 3.5 and 3.4 (n = 2) and for Brahman were 3.8 and 2.5 (n = 2; SEM 0.4). Steer BW, ultrasound measurements for Longissimus area, rib fat, and percent intramuscular fat (%IMF), and PS and EV were collected on arrival at the feedlot and after 113 d on feed. Steers were harvested after reaching a similar rib fat thickness as per breed type. Angus steers ate 1.68 kg/d more DM (P = 0.004), and had greater ADG (P = 0.05), adjusted feed efficiency (P = 0.05), HCW (P = 0.001), carcass marbling score (P = 0.05), ultrasound and carcass fat thickness (P = 0.003), yield grade (P = 0.05), and lower shear force (P = 0.04). TEMP influenced carcass fat thickness (P = 0.03); excited steers had lower fat thickness compared to calm steers. Breed type x temperament interaction influenced carcass marbling score (P = 0.08); Angus calm steers had greater marbling scores than Brahman calm or excited steers. Temperament and breed type influenced carcass quality as indicated by marbling; however, breed type had the greatest effect on growth and carcass characteristics.