Einfluss der Umstellung von Stall- auf Weidefütterung auf den Vormagen pH-Wert von Milchkühen

Summary

To investigate the effect of feed transition from barn feeding to pasture on the course of ruminal pH a study with 8 lactating dairy cows was undertaken. Therefore, an indwelling pH-measurement and data transmitting system was used. The experiment started at 27th March 2012 and a gradual transition from barn feeding to pasture feeding was done (periods P1-P6). After 7 days of barn feeding (P1) animals were given pasture progressively with increasing grazing time from 2 to 7 h/d (P2, day 8-14). In P3 (day 15-21) the cows spent 7 hours/d on pasture. Beginning on day 22, animals had 20 h/d access to pasture (continuous grazing), only semi-daily interrupted for 2 hours for milking and additional feeding (P4-P6). During the barn feeding period (P1), average ruminal pH was highest (6.44) and deviation of H+-ion concentration was lowest. In P2 and P3 ruminal pH depressed significantly (6.24 and 6.21 resp.) and increased again from P4 to P6 (6.30, 6.33, 6.36 resp.). The short-term deviation of H+-ion concentration was highest in the first week of day and night grazing (P4).