Abstract

PORDOMING, Anibal J.; BRESSAN, E.  and  APA, F.J.. Combinación de monensina y viginiamicina en engorde y eficiencia de novillos terminados a corral. RIA. Rev. investig. agropecu. [online]. 2022, vol.48, n.1, pp.78-83.  Epub Apr 06, 2022. ISSN 1669-2314.

Effects of the combination of monensin (Mo) and virginiamycin (Vi) included in a cracked-corn low-effective fiber diet for finishing beef steers. A group of 180 323.22-kg Angus steers were distributed in 12 pens, with 15 animals each. Two treatments, 1) base diet + Mo (Mo), and 2) base diet + Mo + Vi (MoVi), were randomly applied to pens. The diet was based on cracked corn, pelleted wheat middlings, corn distillers’ grain, peanut hulls and a vitamin and mineral premix. Feed was offered by pen daily, twice a day, in 10 to 15% excess. Average daily dry matter intake (DMI) was recorded per pen on a weekly basis. Animals were weighed individually on days 0, 44 and 91. After 91 days on feed animals and reaching 8 mm of back fat were considered finished and taken to a commercial abattoir to slaughter. Individual carcass and hot carcass yields were recorded. Pens were the experimental units for all variables. Effects were detected (P<0.05) for body weight (BW) at weighing dates 44 and 91. Likewise, effects were detected (P<0.05) for average daily gain (ADG), and DMI overall and between weighing dates. On average, MoVi resulted in higher 44-d (P=0,02) and final BW (P=0.01). MoVi animals had higher (P<0.01) ADG during the first 44 days, but, no effects (P=0.17) were detected for the second period. Overall, ADG was 10,8% higher (P<0.01) for MoVi over Mo. Carcasses from MoVi were heavier (P=0.02), but no differences were detected (P=0.40) for hot carcass yield. Clearly, including Vi + Mo in a cracked-corn low-effective fiber diet for feedlot finished steers would improve ADG and DMI over Mo, with no effects on the feed efficiency. Such improvement reflected in carcass weight and did not affect hot carcass yield.

Keywords : monensin; virginiamicyn; steers; feedlot fattening.

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