17 U. Coronel-Robles M.E. Ortega-Cerrilla G.D. Mendoza-Martínez P. Zetina-Córdoba M.T.S. Torres-Esqueda G. Munguía-Ameca M.V. Teco-Jácome Journal of Animal and Plant Sciences JAPS 20162016/02/01 26 1 17-24 1018-7081 NA <p>The objective of this study was to determine the effect of supplementating 10 g/animal/day of&nbsp;<em>Saccharomyces cerevisiae1077</em>&nbsp;(SC1077) or&nbsp;<em>Saccharomyces boulardii</em>1079(SB1079) on dry matter intake (DMI), daily weight gain (DWG), feed efficiency (F:G),&nbsp;<em>in vivo</em>&nbsp;digestibility, pH, and rumen ammonia nitrogen (NH3-N) concentration in rumen liquor, as well as progesterone concentration (P4). Twenty four, six-month old, Holstein heifers were randomly assigned to three treatments (n=8): (T1: Control; T2:10 g/animal/day of SC1077; T3:10 g/animal/day of SB1079). Samples of rumen liquor were taken at 60, 120 and 180 d of the experiment to determine pH and ammonia nitrogen. Determination of&nbsp;<em>in vivo</em>&nbsp;digestibility of DM, NDF, ADF and N was carried out 14 days before the of 60, 120, and 180 d periods. Blood samples were taken to measure P4 concentration. No differences (P &gt; 0.05) were found for DMI, DWG, and F:G from supplementing with&nbsp;<em>S. cerevisiae</em>. Similarly, no differences were reported for rumen pH and rumen NH3-N concentration were not affected (P &gt; 0.05), and&nbsp;<em>in vivo</em> digestibility of DM, NDF, ADF and N (P &gt; 0.05). The P4 concentration was similar (P &gt; 0.05) among the treatments. It is concluded that supplementing Holstein heifers with SC1077 and SB1079 did not improve heifers performance nor modified the progesterone concentration.</p> Saccharomyces, replacement heifers, digestibility Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2016-JAPS-03