SciELO - Scientific Electronic Library Online

 
vol.39 issue5Factors influencing energy demand in dairy farmingMulti-trait and random regression mature weight heritability and breeding value estimates in Nelore cattle author indexsubject indexarticles search
Home Pagealphabetic serial listing  

South African Journal of Animal Science

Print version ISSN 0375-1589

Abstract

PRICE, M.M. et al. The effect of dietary ionophores on feedlot performance of lambs. S. Afr. j. anim. sci. [online]. 2009, vol.39, n.5, pp. 141-144. ISSN 0375-1589.

This study was conducted to evaluate the effect of different rumen fermentation modifiers (ionophores) in feedlot finisher diets on the production performance of S.A. Mutton Merino lambs. Monensin (16.4 mg/kg), lasalocid (33.0 mg/kg) or salinomycin (17.5 mg/kg) was incorporated into a commercial high-protein (398 g CP/kg DM) concentrate. Treatment diets consisted of maize meal (650 g/kg), lucerne hay (150 g/kg) and a protein concentrate (200 g/kg; containing an ionophore or not) to supply isonitrogenous (177 g CP/kg DM) total mixed diets during the experimental period. Sixty lambs (29.7 ± 2.5 kg) were randomly allocated to the treatment groups (n = 15/treatment) and each treatment was further subdivided into five replicates (n = 3/replicate). Individual body weight and average feed intake per replicate were recorded weekly and used to calculate the feed conversion ratio (FCR) and average daily gain (ADG). Ionophore treatment had no effect on any of the feedlot performance parameters measured (feed intake: 1379, 1434, 1534 and 1559 g DM/day; ADG: 298, 314, 340 and 329 g/day; FCR: 4.66, 4.58, 4.51 and 4.74 g DM intake/kg live weight gained for the Control, Monensin, Lasalocid and Salinomycin treatments, respectively. The results suggest the efficiency of the different rumen fermentation modifiers to be similar and financial implications and/or animal preference would influence their usage in sheep diets.

Keywords : Feed efficiency; ionophores; lambs; production.

        · text in English     · pdf in English