Effects of forage ensiling and ration fermentation on total mixed ration pH , ruminal fermentation and performance of growing Holstein‐Zebu cross steers

Our objective was to determine the effect of forage ensiling and ration fermentation on total mixed ration pH , ruminal fermentation and animal performance. Thirty Holstein‐Zebu cross steers were allotted to feeding treatments for 188 days in a randomized complete block design including: fresh grass‐total mixed ration ( GTMR ; pH 4.7), grass silage‐ TMR ( STMR ; pH 4.0) and fermented‐ TMR ( FTMR ; pH 3.5). Average daily gain for STMR was greatest during the first 3 months period; however, that for FTMR tended to be greater than GTMR during the second 3 months period ( P  <   0.10). During the second period dry matter intake for STMR was the greatest ( P  <   0.01), but feed conversion ratio ( P  <   0.01) and cost per gain ( P  <   0.01) were the least for FTMR . Protein digestibility tended ( P  <   0.10) to be greater for FTMR than STMR and fat digestibility was greater ( P  <   0.05) for GTMR and FTMR than STMR . FTMR had less ( P  <   0.01) ruminal NH 3 ‐N content than STMR . Total volatile fatty acids post‐feeding was greatest for GTMR ( P  <   0.01). Ruminal proportions of acetic and butyric acids were greater for FTMR than GTMR ( P  <   0.05); in contrast, propionic acid was greater for GTMR ( P  <   0.05). Utilizing silage or total ration fermentation did not negatively impact on ruminal pH . STMR and F TMR s can be used to maintain performance of growing crossbred Holstein steers.