Influence of Crushing on the pH of Grass Silage

Abstract

THE communication by de Man¹ on this subject makes desirable a brief reference to laboratory experiments here, the results of which are in the press. We have shown that with minced material the influence of added molasses on lactic acid formation is small. Pilot-scale ensilage (15-cwt. quantities) has shown, in addition, that three silages made from chopped grass had pH values of 4.03, 4.00 and 4.13, while another sample of the same crop ensiled at the same time in an unchopped condition had a final pH of 4.46. The carbohydrates liberated by the chopping can replace molasses, and it is conceivable that, with the accompanying liberation of plant amino-acids, a further stimulus is given to the growth of lactobacilli—a possibility suggested by the findings of Dolby and Waters² and Harry³ in connexion with studies on Lactobacillus caseii. Further, the findings of Brouwer⁴, on the interrelationship of dry matter content and pH in silage, mentioned by de Man, have been confirmed by Brown⁵ and extended by myself⁶ to include the nitrogen content as well.