Manipulating rumen fermentation and methanogenesis using an essential oil and monensin in beef cattle fed a tropical grass hay

• Published in: Animal feed science and technology 2015-02, Vol.200, p.25-34
• Main Authors: Tomkins, Nigel W., Denman, Stuart E., Pilajun, Ruangyote, Wanapat, Metha, McSweeney, Chris S., Elliott, Robert
• Format: Article
• Language: English
• Subjects: Abatement; Cattle; Chloris gayana; CRINA; Greenhouse gas emission; Ionophore; Methanobrevibacter; Methanogens; Ruminantia
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2014.11.013

•CRINA does not significantly reduce enteric methanogenesis.•Steers given monensin at a rate of 250mg/d have DM intakes reduced by 18%.•Methyl coenzyme-M reductase clone libraries were generated from rumen microbial DNA.•Correlated decline in methanogens was out of phase with methane production. The objective of this study was to determine if a specific blend of essential oils (CRINA® Ruminants) compared to monensin could reduce enteric methane production in beef cattle fed medium to low quality Rhodes grass (Chloris gayana) hay. Five Brahman steers [mean live weight (LW); 226kg] were allocated to one of five groups: control (no additive), CRINA1 (CRINA 1g/d), CRINA2 (CRINA 2g/d), Mon1 (monensin 60mg/d) and Mon2 (monensin 250mg/d) as a 5×5 Latin square. Individual LW, dry matter (DM, kg/d) intake, rumen pH, fermentation patterns, and ruminal fungal colonisation was measured. Methyl coenzyme-M reductase (mcrA) clone libraries (methanogen diversity) were generated from microbial DNA extracted from the rumen. Total methane production (g/d) was measured over 24h using open circuit respiration chambers. The DM intake for animals given CRINA at either dose rate was not different (P>0.05) to the control (5.4kg/d). However, Mon2 (P