Effects of dietary virginiamycin on performance and liver abscess incidence in feedlot cattle.

Abstract

The effects of dietary virginiamycin level on performance and liver abscesses in feedlot cattle were evaluated in seven dose-response studies. Steers and heifers were fed finishing diets ranging in energy content from 1.34 to 1.51 Mcal of NEg/kg of DM. In all studies, virginiamycin added to the diet improved average daily gain and(or) feed conversion, with no substantial effect on dry matter intake. Pooled analyses of four studies providing virginiamycin at 11.0, 19.3, and 27.6 mg/kg of DM in the complete diet indicated that growth and feed conversion were linearly improved (P < .05); feeding 19.3 mg/kg improved these measurements by 3.0 and 3.8%, respectively. Overall incidence (score 0 vs score 1, 2, and 3) and severity (score 0, 1, and 2 vs score 3) of liver abscesses were reduced (P < .01) by feeding virginiamycin at either 19.3 or 27.6 mg/kg. Linear plateau modeling indicated that the effective dose range for virginiamycin in feedlot diets (DM basis) was 19.3 to 27.3 mg/kg for increasing average daily gain, 13.2 to 19.3 mg/kg for improving feed conversion, and 16.5 to 19.3 mg/kg for reducing liver abscess incidence.

Combined use of ionophore and virginiamycin for finishing Nellore steers fed high concentrate diets

“…As previously mentioned, this may have occurred due to changes in ruminal fermentation promoted by virginiamycin supplementation. These results are similar to others reported in the literature, in which estimated NE m and NE g of the diets were higher for feedlot beef cattle supplemented with virginiamycin when compared with control animals (Rogers et al, 1995;Salinas-Chavira et al, 2009).…”

“…The isolated utilization of ionophore, like monensin or salinomycin, or non-ionophore antibiotics, such as virginiamycin, as growth promoter feed additives has been thoroughly investigated. The results are consistent in demonstrating improvements on animal performance (Rogers et al, 1995;Zinn, 1986). Moreover, Silva et al (2004) suggested that virginiamycin and ionophore may have an additive effect on growth performance when used in combination, but with no substantial effects on carcass characteristics.…”

“…Even though KPH was higher (p ≤ 0.05) for steers receiving only salinomycin, LM area and backfat thickness did not differ (p > 0.05) between treatments, suggesting that the physical composition of the carcasses were similar for animals receiving only the ionophore or both additives. The supplementation with virginiamycin usually has no adverse effects on carcass quality (Rogers et al, 1995). Silva et al (2004) also did not observe differences in carcass traits, except for backfat thickness, which was greater for Nellore steers fed salinomycin in comparison with those receiving the combination of salinomycin and virginiamycin.…”

“…Similar results were observed by Silva et al (2004), in which G:F of finishing Nellore steers did not differ among groups (control, salinomycin, virginiamycin, or both additives). On the other hand, some authors reported linear improvements in feed efficiency when cattle were fed increasing levels of virginiamycin (Rogers et al, 1995;Salinas-Chavira et al, 2009).…”

Desempenho e metabolismo ruminal em bovinos de corte em sistema de pastejo no periodo seco do ano recebendo virginiamicina na dieta

“…Este antibiótico não ionóforo atua por meio de ligação com os ribossomos, inibindo a síntese de proteína de alguns microrganismos (ROGERS et al, 1995).…”