The objectives were to accurately quantify enteric methane (CH4) emissions for first lactation dairy cows and to use these data to develop CH4 prediction equations. Calorimeter measurements and production data were used to calculate CH4 emissions for Holstein-Friesian (HF, n = 32) and Norwegian (n = 32) first lactation cows during a 305-d lactation period. Methane outputs were similar between HF
... [Show full abstract] and Norwegian (123 vs. 126 kg/305 d) when offered high-concentrate diets, but HF produced more CH4 (P < 0.05) than Norwegian (105 vs. 98 kg/305 d) when given low-concentrate diets. The HF offered high-concentrate diets had a lower (P <.05) CH4 emission per energy-corrected milk yield (16.3 g/kg) than the other three treatments (19.7–20.4 g/kg). These data were then used to develop CH4 prediction equations, which provide an alternative approach to estimate enteric CH4 emissions for HF and Norwegian first lactation dairy cows.
