Der Einfluß des Polyätherantibiotikums “Monensin” auf Pansenfermentation und Mastergebnisse von Milchrindkreuzungsbullen und Masthybriden

Abstract

The influence of the polyether antibiotic Monensin on the rumen fermentation and the fattening results of fattening hybrids (genotype 61) and crossbreeding bulls of dairy cattle (genotype 19) was ascertained in two feeding experiments (E1 and E2). Caused by the supplementation of the antibiotic, the molar acetate quota decreased (1.9 to 4.8 Mol %) and the molar propionate concentration increased (0.2 to 2.9 Mol %) in the rumen fluid of crossbreeding bulls of dairy cattle and of fattening hybrids, it is, however, below the range described in literature. With the exception of the fattening hybrids in E1, the supplementation of Monensin resulted in the diminished intake of dry matter, the daily increase of the live weight of all groups of fattening bulls was higher (E1: fattening hybrids: 1106 resp. 1199g; crossbreeding bulls of dairy cattle: 1037 resp. 1058 g; E2: 997 resp. 1024 g; 895 resp. 981 g without resp. with Monensin). After the Monensin supplementation the crossbreeding bulls of dairy cattle showed a distinctly bigger decrease of the feed intake and a rise of the live weight increase than the fattening hybrids. For this reason the genotypes of dairy cattle showed in both experiments after the Monensin supplementation a bigger decrease of expenditure (0.8 resp. 7.1% and 5.6 resp. 11.3% in experiments 1 and 2) than the fattening hybrids.