Effects of TMR and Separate Feeding System on Ruminal Methane Production, Total Digestibility, Rumen Metabolic and Microbial Profile

Abstract

P < 0.005) compared to those fed TMR. Also, cattle those received SF exhibited significantly lower (P < 0.05) ruminal pH and higher (P < 0.05) ammonia-N concentration and total VFA compared to those fed TMR. A significantly (P < 0.05) lower acetate: propionate ratio (2.2 vs. 2.6) in those fed SF reflected the shift in hydrogen transfer towards the formation of more propionate than those fed TMR. Significantly higher levels of isobutyrate and isovalerate (P < 0.05) were observed in those fed SF compared to those fed TMR. The total tract digestibility of CP, NDF, and OM were not affected by the feeding system. 16SrRNA analysis revealed the changes in the representation of bacteria belonging to the phyla Bacteroidetes and Firmicutes between the feeding system. TMR feeding system significantly increased (P < 0.1) the Leuconostoc and RFN20 population. SF system exhibited higher abundance of Coprococcus. Overall, these results indicate that SF significantly reduces methane emission from ruminants and increases VFA production without affecting the total tract digestion when compared to TMR.

Limited researches are available on effect of TMR (Total Mixed Ration) and SF (Separate feeding) system on ruminant methane production. Two experiments were performed at two different levels of daily feed intake (2.4 and 2.0 % of BW) to investigate methane production from the two different feeding systems by using a triplicated 2 × 2 Latin square design. Each experiment was conducted using six male Holsteins with BW ranging from 230–570 kg. Animals were provided either SF or TMR containing 73% concentrate and 27% forage, with the same ratio of same ingredients and grasses, twice a day. No differences (P > 0.1) in methane emissions were observed in animals fed diets at 2.4% of BW in experiment 1. Animals fed SF at 2% BW in experiment 2 emitted significantly more methane (114.5 vs. 138.5 L/d

P < 0.005) and lost more methane energy (3.39 vs. 4.08%