Enteric methane emission, milk production, and composition of dairy cows fed 3-nitrooxypropanol

This study examined the effect of 3-nitrooxypropanol (3-NOP), an investigational substance, on enteric methane emission, milk production, and composition in Holstein dairy cows. Following a 3-wk covariate period, 48 multi- primiparous cows averaging (± standard deviation) 118 ± 28 d milk, 43.4 8 kg/d yield, 594 57 kg body weight were blocked based days emission randomly assigned to 1 2 treatment groups: (1) control, no 3-NOP, (2) 3-NOP applied at 60 mg/kg feed dry matter. Inclusion was through total mixed ration fed for 15 consecutive weeks. Cows housed freestall barn equipped with Calan Broadbent Feeding System (American Inc., Northwood, NH) monitoring individual matter intake ad libitum once daily. Enteric gaseous emissions (methane, carbon dioxide, hydrogen) measured using 3 GreenFeed (C-Lock Rapid City, SD) units. Dry intake, cow weight, change not affected by 3-NOP. Compared control group, decreased daily intensity 26, 27, 29%, respectively. dioxide affected, hydrogen increased 6-fold Administration had energy-corrected yields efficiency, fat urea nitrogen concentrations, yield but other effects components. Concentration C6:0 C8:0 sum saturated fatty acids Total trans polyunsaturated In this experiment, without affecting high-producing