Abstract #850

# 850
A novel inhibitor persistently decreased enteric methane emission and increased weight gain of high-producing Holstein cows without negatively affecting milk production.
Alexander N. Hristov*1, Joonpyo Oh1, Fabio Giallongo1, Michael T. Harper1, Holley Weeks1, Antonio F. Branco2, Peter J. Moate3, Matthew H. Deighton3, S. Richard O. Williams3, Maik Kindermann4, Stephane Duval5, 1Department of Animal Science, The Pennsylvania State University, University Park, PA, 2Departamento de Zootecnia, Universidade Estadual de Maringá, Maringá, Parana, Brazil, 3Agriculture Research Division, Department of Economic Development Jobs Transport and Resources, Ellinbank, Victoria, Australia, 4DSM Nutritional Products, Animal Nutrition and Health, Basel, Switzerland, 5DSM Nutritional Products France, Research Centre for Animal Nutrition and Health, Saint Louis Cedex, France.

This study investigated the effect of a CH4 inhibitor, 3-nitrooxypropanol (3NOP), on enteric CH4 emissions in lactating Holstein cows. The experiment was a randomized block design with 48 cows (DIM, 77 ± 3.9; lactations, 2.2 ± 0.15), with a 2-wk covariate and a 12-wk data collection periods. Treatments were: control (no additive) and 3NOP applied at 40, 60, and 80 mg/kg feed DM. 3NOP was mixed with the TMR and cows were fed once daily. Methane and H2 emissions were measured using 2 methods, the GreenFeed system and the modified SF6 tracer technique, during the covariate period and experimental wk 2, 6, 9, and 12. Compared with the control, 3NOP decreased the average CH4 emission by 25, 31, and 32%, respectively, when measured using the GreenFeed system (481, 363, 333, and 329 g/cow/d; SEM = 15.9; P < 0.001). Similar inhibition of CH4 emission by 3NOP was observed when determined using the SF6 technique. Hydrogen emissions from the control cows were negligible throughout the experiment (on average 0.02 g/cow per day), but increased considerably for the 3NOP treatments (0.48, 0.96, and 1.27 g/cow per day, respectively; SEM = 0.116, P < 0.001). Methane emissions per kg of DMI or ECM were on average 29 and 31%, respectively, lower for the 3NOP treatments compared with the control. Treatment had no effect on DMI (27.8 ± 0.45 kg/d), milk production (45.5 ± 1.21 kg/d), and feed efficiency (1.65 kg/kg). Milk composition was not affected by 3NOP. Milk protein and lactose yields were increased (P ≤ 0.05) by 3NOP. Body weight gain during the experiment was about 168 g/d greater (P = 0.05) for the 3NOP-treated cows. Apparent total-tract digestibility of DM, OM, CP, and ADF were quadratically increased (P ≤ 0.06) by 3NOP compared with the control. This experiment demonstrated that enteric CH4 emissions from ruminant animals can be successfully decreased by the use of a CH4 inhibitor, without negatively affecting animal productivity. If adopted, this mitigation practice could substantially reduce greenhouse gas emissions from the ruminant livestock sector.

Key Words: methane, hydrogen, 3-nitrooxypropanol