PSXIII-8 Assessment of additive used to formulate molasses lick blocks to reduce beef cattle methane emissions.

Abstract This study analyzed a novel product used in the manufacture of molasses lick blocks (LB) to reduce methane (CH4) emissions and improve productivity from grazing beef cattle. The effectiveness of four products was evaluated under in vitro conditions. Product 3 was the most effective in all in vitro parameters reducing CH4 production by over 90% at 6% dose compared to the control (P < 0.05). Consequently, the selected product was incorporated into grain-based pellets to achieve a target of 0, 100, and 200 g/head per day product intake delivered via a GreenFeed unit. Results indicated that steers treated with the product pellets tend to have a significant reduction of up to 10.7 % in CH4 production compared to the steers that received the pellets without product (P = 0.07). Also, CH4 yield (g CH4 kg-1 DMI) from steers treated with 100 and 200 g/head per day product supplement were 11.7% and 7.5% lower (P < 0.01) than those without product supplement, respectively. Additionally, CH4 intensity tended (P = 0.06) to be 16.8 % lower for the animals fed 100 and 200 g pellets compared with the control. Finally, the average product intake (g/head per day) was negatively correlated with CH4 intensity and yield and positively with water consumption and ADG (P < 0.05). In conclusion, the product used for manufacturing LB supplements appears to have a beneficial effect in reducing methane yield (by up to 11.7%), without adverse effect on animal performance. Moreover, the trend reduction in CH4 production (up to 10.7%) and intensity (up to 16.8%) indicate a potential for product 3 to contribute to lower methane emission from beef steers. However, greater doses of product over longer periods of feed supplementation may need to be assessed to discard possible negative effects of microbial adaptation.