Uso de Saccharomyces cerevisiae y monensina sódica en raciones con distinto nivel de proteína para vaquillas holstein

Abstract

Zaragoza HC, Ayala OJ, Mendoza MGD. Tec Pecu Mex 2001,39(3)207-214. It has been reported that ionophores and yeast culture can modify duodenal amino acid flow, therefore those additives were included in heifers rations with three levels of protein. Twenty seven Holstein heifers were individually fed (189 kg body weight), 10 months of age according to a completely randomized design with a 3 x 3 factorial arrangement, protein levels (12, 14 and 16 % CP), and additives (none, 10 g/ d of Saccharomyces cerevisiae, and 30 ppm monensin). There was no interaction among protein level and feed additive. Feed additives did not affect dry matter intake, daily gain, feed conversion or body condition. Dry matter intake was reduced with the medium protein level, however, no differences were observed in the rest of the variables. Estimation of metabolizable lysine and methionine indicated that requirements were met. Lack of interaction between feed additives and protein level indicates that amino acid flow was not altered. Heifers can be fed with rations with 12 % CP if requirements of metabolizable amino acids are met.