[The effects of feeding NaOH-treated straw to dairy cows with special reference to acid-base balance and ruminal...

Four moderately yielding cows were for 9 weeks given 4.8 kg dry substance of unneutralized, alkali-treated straw and 150 g urea, implying a great surplus of Na and alkali. With the exception of tympanitis on one occasion, no symptoms of disease were found. In spite of subfeeding with protein, no evident reduction in yield occurred during the experimental period. The rumen function was not negatively influenced by the excess of Na and alkali. The Na content in blood serum increased during the experimental period. At the same time there was an increase of bicarbonate and base excess in arterial blood. The alkalosis was, however, only mild and well compensated.