Rumen fermentation characteristics in pre-weaning calves receiving yeast culture supplements

Abstract

In an experiment with 45 neonatal male Holstein calves, effects of yeast cultures Yea-Sacc<sup>®</sup> 1026 (SC) containing <I>Saccharomyces cerevisiae</I> (strain 1026) and Vitex (KF) containing <I>Kluyveromyces fragilis</I> (strain Jürgensen) on rumen fermentation characteristics were determined. From day 4 to day 56 of age, the calves were allocated to one of the three dietary treatments (Control, SC, and KF) of 15 animals each, placed in individual pens, and fed 4 l of whole milk twice daily and a basal concentrate mixture ad libitum as calf starter feeds. The control treatment was not supplemented with yeast culture. The yeast culture supplements Yea-Sacc<sup>®</sup> 1026 and Vitex were top-dressed at 10 g/calf daily on the basal concentrate mixture of treatments SC and KF, respectively. At the end of the experiment (day 56), all calves were slaughtered and the rumen fluid was analysed. The administration of yeast cultures Yea-Sacc<sup>®</sup>026 and Vitex to calves did not affect final body weight (BW), BW gain, dry matter intake, feed conversion ratio, ruminal pH, lactic acid concentration and the molar proportion of propionic acid, but it decreased (<I>P</I> < 0.05) the total volatile fatty acid concentration and the molar proportion of butyric acid, and increased (<I>P</I> < 0.05) the molar proportion of acetic acid and the acetate to propionate ratio. In addition, the microbial cellulolytic activity was higher in calves that received both yeast cultures compared to the control treatment. The results of this study suggest that the ruminal fermentation was more stable in calves receiving yeast culture supplements.