[The influence of different straw-based ration type on fermentation and production of volatile fatty acids in the rumen of lactating cows. 3. Rumenal fermentation processes and milk yield criteria after using a low-fiber straw pellet batch as basal ration component and a fully pelleted straw-based ration].

Lactating Black-Pied (DSR) cows were used to study, over a period of 100 days, the influence of different basal ration types (I-treated wheat straw pellets, low-fibre; II- monodiet pellets containing 48% of wheat straw; III = conventional rations based on fresh forage and arable root crops) on the molar fermentation pattern and the daily rate of VFA production and some milk yield criteria. Ration types I and II results in almost equal fermentation patterns of the VFA; as against the conventional ration types (III) a significantly higher molar acetate propertion as well as a highly significantly decreased molar proportion of iso-acids were found. The daily rated of VFA production relativated to energy intake were as follows (in the order of the ration types mentioned): 4.9, 4.2 and 5.0, and 3.3, 2.5 and 3.3 moles per 1,000 anergetic feed equivalents (cattle) after 30 and 100 days of feeding, respectively. In both trials, only about 80% of the relative VFA production of the straw pellet-concentrate (I) and conventional (III) ration types were found when feeding fully pelleted diets (II). On account of the relatively wide variation of the experimental results no statistically secured findings were obtained as to the milk yield criteria, but ration type II produced some 200 and 300 kg milk less thant ration types I and III, respectively, during the 100-day experimental period.