Effect of dry cow feeding strategy on rumen pH, concentration of volatile fatty acids and rumen epithelium development

Two experiments, including eight and six dairy cows, were carried out to investigate the effect of dry cow feeding on rumen pH and volatile fatty acid (VFA) concentration during the dry period and early lactation, and the effect of dry cow feeding on the ruminal epithelium status at the end of the dry period. The recommended energy level was fed to dry cows as a roughage-based diet (control group) or as a concentrate-based diet given as 4 kg barley in the morning plus a small amount of roughage in the afternoon (VFA load group). During lactation, both groups were fed the same diet nd libitum. Rumen liquid was sampled on days - 10, 8 and 28 peripartum. Compared with controls on day -10, the pH was significantly lower in the VFA load group 2-7 h postfeeding, while the concentration of propionate and butyrate was significantly higher in the period after morning feeding. Eight days postpartum, the cows on the VFA load treatment had a significantly lower dry matter (DM) intake (11.6 +/- 0.7 versus 14.2 +/- 0.7 kg), a more rapid decrease in pH and to a lower level after the morning feeding. The same tendency was observed in pH on day 28 postpartum but differences in DM intake were not significant. Macroscopic and histological examinations of the rumen epithelia showed no differences between the feeding strategies. In conclusion, using a moderate feeding level with a daily VFA load in the dry period did not change the ruminal epithelium status, postpartum rumen pH or DM intake positively.