Ruminal methane emissions, metabolic, and microbial profile of Holstein steers fed forage and concentrate, separately or as a total mixed ration

Abstract

Few studies have examined the effects of feeding total mixed ration (TMR) versus roughage and concentrate separately (SF) on ruminant methane production. Therefore, this study compared differences in methane production, ruminal characteristics, total tract digestibility of nutrients, and rumen microbiome between the two feeding methods in Holstein steers. A total six Holstein steers of initial bodyweights 540 ± 34 kg were divided into two groups and assigned to a same experimental diet with two different feeding systems (TMR or SF) in a crossover design with 21 d periods. The experimental diet contained 73% concentrate and 27% forage and were fed twice a day. The total tract digestibility of crude protein, neutral detergent fibre, and organic matter were not affected by the two different feeding systems. Steers fed TMR emitted more methane (138.5 vs. 118.2 L/d; P < 0.05) and lost more gross energy as methane energy (4.0 vs. 3.5% gross energy intake; P = 0.005) compared to those fed SF. Steers fed TMR had greater (P < 0.05) total volatile fatty acid (VFA), ammonia-N concentrations and propionate proportion of total VFA at 1.5 h, whereas lower after that compared to steers fed SF. The greater (P < 0.05) acetate: propionate ratio at 4.5 h for steers fed TMR reflected the shift of H2 sink from propionate towards acetate synthesis. The lower (P < 0.05) isobutyrate and isovalerate proportions of total VFA observed in steers fed TMR implies decrease in net consumption of H2 for microbial protein synthesis compared to SF. There were no differences in both major bacterial and archaeal diversity between TMR and SF, unlike several minor bacterial abundances. The minor groups such as Coprococcus, Succiniclasticum, Butyrivibrio, and Succinivibrio were associated with the changes in ruminal VFA profiles or methanogenesis indirectly. Overall, these results indicate that SF reduces methane emissions from ruminants and increases propionate proportion of total VFA without affecting total tract digestion compared to TMR. There were no evidences that the response differed due to different major underlying microbial population.

Holstein and Jersey Steers Differ in Rumen Microbiota and Enteric Methane Emissions Even Fed the Same Total Mixed Ration

“…Furthermore, the PCoA plot and PCoA ellipses corresponding to the overall rumen microbiota of the two breeds were separated, indicating distinct different rumen microbiota harbored by each breed even fed the same TMR. Consistent with other studies (Bharanidharan et al, 2018;Difford et al, 2018;Xue et al, 2018), Prevotella had the most predominance in both breeds and at both sampling hours. Likewise, Pr.…”

“…The average body weight (BW) was calculated as (the initial BW + the final BW)/2, and average daily gain (ADG) was recorded for the last 10 days of the experimental period. The TMR was sampled twice (at days 7 and 28) during the feeding trial, and the dry matter content was determined using a hot-air oven at 65°C for 72 h ( Bharanidharan et al, 2018 ). The chemical composition of the TMR was analyzed following the standard methods ( Aoac, 2005 ).…”

Effects of High Forage/Concentrate Diet on Volatile Fatty Acid Production and the Microorganisms Involved in VFA Production in Cow Rumen

“…The ratio of acetate, propionate, and butyrate generated in the rumen is affected by the type of forage and the species and quantity of rumen bacteria [5,6]. Meanwhile, sampling time is also an important factor affecting VFAs production [7].…”

“…TVFA: Total volatile fatty acid; 2 A/P: Acetate/ Propionate; 3 BF(0), before feeding (0 h); 4 AF(4), after feeding (4 h);5 SEM for feed × time;6 NS, not significant (p > 0.05); *, (p < 0.05); **, (p < 0.01).…”

Betaine Modulates Rumen Archaeal Community and Functioning during Heat and Osmotic Stress Conditions In Vitro

“…Similar findings have been previously reported by Bennink et al [ 34 ] who found 12.4% less CH 4 production with salt-induced elevated osmolality in the rumen of wethers. The earlier studies did not focus on the archaea community in relation to high osmolality, but feeding high-grain diets, which elevates ruminal osmolality [ 35 ], have been shown to reduce CH 4 production and formation [ 36 , 37 ], which favour the possible reduction or changes in archaea community structure. The current modifications in archaea diversity due to heat stress were too limited to affect the gas production parameters, which indicates that the metabolic role of archaea was relatively sustained unlike during osmotic stress conditions.…”