caa a22 4500 397552467 CHVBK 20180308164754.0 cr unu---uuuuu 161202e199608 xx s 000 0 eng 10.1111/j.1574-6941.1996.tb00319.x doi (NATIONALLICENCE)oxford-10.1111/j.1574-6941.1996.tb00319.x The effect of pH on ruminal methanogenesis [Elektronische Daten] [Jo Ann S. Van Kessel, James B. Russell] When a fistulated cow was fed an all forage diet, ruminal pH remained more or less constant (6.7 to 6.9). The ruminal pH of a concentrate-fed cow decreased dramatically in the period soon after feeding, and the pH was as low as 5.45. Mixed ruminal bacteria from the forage-fed cow converted CO2 and H2 to methane, but the ruminal fluid from the concentrate-fed cow did not produce methane. When the pH of the ruminal fluid from the concentrate-fed cow was adjusted to pH 7.0, methane was eventually detected, and the absolute rate constant of methane production was as high as the one observed with ruminal fluid from the forage fed cow (0.32 h−1). Based on the zero-time intercepts of methane production, it appeared that the concentrate-fed cow had fewer methanogens than the forage-fed cow. When the mixed ruminal bacteria were incubated in a basal medium containing 100 mM acetate, methanogenesis was pH-dependent, and no methane was detected at pH values less than 6.0. Because the removal of acetic acid completely reversed the inhibition of methanogenesis, it appeared that volatile fatty acids were causing the pH-dependent inhibition. Based on these results, concentrate diets that lower ruminal pH may provide a practical means of decreasing ruminal methane production. © 1996 Federation of European Microbiological Societies. Published by Elsevier Science B.V. Rumen nationallicence Methanogenesis nationallicence pH nationallicence Volatile fatty acid nationallicence Van Kessel Jo Ann S. Section of Microbiology, Cornell University, Wing Hall, Ithaca, NY 14853, USA aut Russell James B. Section of Microbiology, Cornell University, Wing Hall, Ithaca, NY 14853, USA aut FEMS Microbiology Ecology Blackwell Publishing Ltd 20/4(1996-08), 205-210 20:4<205 1996 20 femsec https://doi.org/10.1111/j.1574-6941.1996.tb00319.x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1111/j.1574-6941.1996.tb00319.x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Van Kessel Jo Ann S. Section of Microbiology, Cornell University, Wing Hall, Ithaca, NY 14853, USA aut NATIONALLICENCE 700 1- Russell James B. Section of Microbiology, Cornell University, Wing Hall, Ithaca, NY 14853, USA aut NATIONALLICENCE 773 0- FEMS Microbiology Ecology Blackwell Publishing Ltd 20/4(1996-08), 205-210 20:4<205 1996 20 femsec Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford