Effects of dietary inclusion of 3 Nordic brown macroalgae on enteric methane emission and productivity of dairy cows

Macroalgae has gained increasing interest as antimethanogenic feed additives for cattle, but most in vivo studies are limited to investigating effects of the red macroalgae Asparagopsis spp. Hence, this study aimed investigate CH4 mitigating potential 3 brown from Northern hemisphere when fed dairy cows, and on intake, milk production, digestibility, animal health indicators. The experiment was conducted a 4 × Latin square design using lactating rumen, duodenal, ileal cannulated Danish Holstein cows. cows were total mixed ration (TMR) without any or same TMR diluted with, dry matter basis, either 4% ensiled Saccharina latissima, Ascophyllum nodosum (NOD), 2% Sargassum muticum (MUT). Each period consisted 14 d adaptation, digesta blood sampling, gas exchange measurements respiration chambers. Milk yield intake (DMI) recorded daily. Blood sampled 13 16 analyzed status None species affected emission. Moreover, DMI also unaffected. Total-tract digestibility crude protein significantly lower NOD compared with other diets, additionally, diet tended reduce total-tract neutral detergent fiber MUT. biomarkers did not indicate negative dietary inclusion cow health. In conclusion, none reduced emission affect production whereas nutrients observed A. added. diets would be allowed commercial herds due high contents iodine, cadmium, arsenic.