The effects of technology use in feedlot production systems on feedlot performance, carcass characteristics, and feeding behaviors of crossbred beef steers

Abstract Text: The objectives of this study were to examine the effects of a technology enhanced system compared to an all-natural production program on feedlot performance, feeding behaviors and carcass characteristics.  Crossbred beef steers (n = 54; initial BW = 391 ± 2.6 kg) were randomized to one of two treatments in a RCBD (13-14 steers/pen; 27 steers/treatment).  Treatments consisted of an all-natural treatment (NAT), and a conventional treatment (CONV-Z).  The NAT cattle received no growth promoting technologies. The CONV-Z cattle were implanted with 40 mg of estradiol and 200 mg of trenbolone acetate on d 0, and were fed 33 and 9 mg/kg of monensin and tylosin daily, respectively as well as zilpaterol hydrochloride at 6.76 mg/kg (90% DM basis) for the last 20 DOF.  Gain was improved by 45.1% (1.77 vs. 1.22 kg/d; P < 0.01) and feed efficiency by 45.5% (0.163 vs. 0.112; P < 0.01) for CONV-Z steers compared to NAT steers.  Daily water intake was numerically greater for NAT steers compared to CONV-Z steers consistently throughout the study (56.26 vs. 53.59 L/d; P = 0.43).  Thus, total water and feed efficiency was improved by 50% for CONV-Z steers compared to NAT steers (0.027 vs. 0.018; P < 0.01).  NAT steers consumed more (8.22 vs 7.59 meals/d; P = 0.03), smaller feed meals (1.34 vs 1.46 kg/meal; P = 0.02), resulting in more time spent at the feed bunk (85.36 vs 73.19 min/d; P < 0.01) throughout the day compared to CONV-Z steers.  Water meal length was greater for NAT steers compared to CONV-Z steers (3.23 vs 2.58 min/meal; P < 0.01), resulting in more time spent at the water trough throughout the day (23.71 vs. 17.80 min/d; P < 0.01).  Dressing percentage was increased by 2.17 percentage units (65.31 vs. 63.14; P < 0.01) for CONV-Z steers compared to NAT steers, resulting in a 48 kg heavier carcass (388 vs. 340, kg; P < 0.01).  Longissimus muscle area was increased by 11.09 cm² (87.25 vs. 76.15, cm²; P < 0.01) for CONV-Z steers compared to NAT steers, and marbling score was greater for NAT steers compared to CONV-Z steers (504 vs. 410; P <0.01).  The results of this experiment show that CONV-Z production improves feedlot performance and resource-use efficiency compared to NAT with differences in feed and water intake behavior.  

Keywords: beef cattle, conventional, natural