Virginiamycin and sodium monensin supplementation for beef cattle on pasture

H.M Saturnino,F.A Barbosa,P.M Costa,I.C.F Maciel,V.M.R Malacco,J.M.C Andrade Júnior,G.H.B Maia Filho

doi:10.1590/1678-4162-10659

H.M Saturnino, F.A Barbosa + Show 5 more

Open Access

https://doi.org/10.1590/1678-4162-10659

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Abstract

ABSTRACT The aim of this paper was to evaluate the effects of including virginiamycin (VM), sodium monensin (MON) or the association (VM+MON) in the energetic mineral supplement, on the intake and performance of beef cattle on pasture. Forty Nellore heifers with 24 months of age and initial body weight (BW) of 251.5±16.6kg, were distributed in four treatments in a randomized block design. Treatments consisted of adding VM, MON or VM+MON to the supplement (CONT). Additive concentrations were defined to reach a dose of 40 to 45mg/100kg BW. The herbage allowance was not a limiting factor for the animals’ intake. Supplement intake was lower than expected, with 33.0, 18.8 and 26.3mg per 100kg BW for VM, MON and VM+MON, respectively. Dry matter intake (DMI, mean=2.65% BW) and animal performance were not affected by the inclusion of additives. The average daily gain (ADG) was 0.561kg/animal day-1. The inclusion of additives in energetic mineral supplement does not affect the DMI and the ADG of grazing animals. The variability in supplement intake and daily dose intake of additives may have influenced the performance of the animals. Monensin inclusion presented the less expensive supplementation cost, due to reduction in supplement intake without changing weight gain.

Highlights

The use of technologies to increase the feed efficiency and weight gain of animals are increasingly recommended for grazing systems, due to the fact that about 90% of the Brazilian bovine herd is exclusively fed on pasture (Silva et al, 2016)
Herbage allowance (HA) in leaf and steam DM (LSDM) was greater than 11% in all the evaluated months (Figure 2)
The accumulated rainfall in March and April (144.3mm, Figure 1) and pasture fertilization could explain the higher crude protein (CP) content, causing a smaller decrease in the Total digestible nutrients (TDN): PB when compared to the other months

Summary

Introduction

The use of technologies to increase the feed efficiency and weight gain of animals are increasingly recommended for grazing systems, due to the fact that about 90% of the Brazilian bovine herd is exclusively fed on pasture (Silva et al, 2016). The anti-microbial growth promoters, such as antibiotics ionophores or nonionophores, are alternatives to improve the efficiency of nutrient utilization, since they can manipulate ruminal fermentation trough changes in the microbial population (Tedeschi et al, 2011). In grazing animals, these alterations in pattern of rumen fermentation promoted by additives can reduce methanogenesis, a strategy to mitigate greenhouse gases (Guan et al, 2006), suppling the increasing demands for sustainable livestock production (Godfray et al, 2010; Garnett et al, 2013). The use of monensin and virginiamycin association in beef cattle supplements, to our knowledge, is not yet fully characterized; this combination has the potential to maximize nutrient absorption in the rumen and increase animal performance

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