Nitrate may lower methane production in ruminants by competing with methanogenesis for available hydrogen in the rumen. This study evaluated the effect of 4 levels of dietary nitrate addition on enteric methane production, hydrogen emission, feed intake, rumen fermentation, nutrient digestibility, microbial protein synthesis, and blood methemoglobin. Digesta content from duodenum, ileum, and feces, and rumen liquid of cannulated dairy cows were collected, after which methane production and hydrogen emissions were measured in respiration chambers. Nitrate lowered methane production linearly with minor effects on rumen fermentation and no effects on nutrient digestibility.
Olijhoek D, Hellwing A, Brask M, Weisbjerg M, Højberg O, Larsen M, Dijstra J, Erlandsen E, Lund P
Journal of Dairy Science