Comparisons of technologies in beef production systems

Abstract

Beef steers (n = 180; initial BW = 250 � 19 kg) were randomized to one of two treatments in the pasture phase. Steers were implanted with 40 mg of TBA, 8 mg estradiol, and 29 mg tylosin tartrate (Conventional; CONV-Z) or received no implant (Natural; NAT). Conventional steers had improved ADG and a heavier final BW compared with NAT steers. Following the pasture phase, steers were assigned to a 2 x 2 factorial in the feedlot phase. Production system (NAT vs. CONV-Z) was maintained from the pasture phase, and the second factor was 7 vs. 12% roughage (DM basis; LOW vs. HIGH). Conventional steers ate more feed, gained faster and were more efficient compared with NAT steers. Hot carcass weight and LM area was increased for CONV-Z steers compared with NAT steers. Conventional steaks had increased slice shear values and Warner-Bratzler shear force compared with NAT steaks. Steaks from cattle fed CONV-Z had higher moisture content, lower lipid content, higher protein and higher ash content than steaks from NAT cattle. In experiment 2, steers (n = 336; initial BW = 379 � 8 kg) were randomized to similar treatments. CONV-Z steers gained faster and were more efficient than CONV steers, and CONV steers gained faster and were more efficient than NAT steers. Hot-carcass weight was increased for CONV-Z steers compared to CONV steers and compared to NAT steers. In experiment 3, beef steers (n = 54; initial BW = 391 � 3 kg) were randomized to one of two treatments, an all-natural treatment (NAT), and a conventional treatment (CONV-Z). Gain and feed efficiency was improved for CONV-Z steers compared to NAT steers. Daily water intake was numerically greater for NAT steers compared to CONV-Z steers and total feed and water efficiency was improved by 50% for CONV-Z steers compared to NAT steers. Natural steers spent more time at the feed and water bunk than CONV-Z steers. Hot-carcass weight and LM area were increased for CONV-Z compared to NAT steers. Data from these experiments show that conventional production increases animal performance and net return without drastically affecting meat quality.