Enteric methane emission and digestion in dairy cows fed wheat or molasses

Abstract

The aim of this experiment was to measure enteric methane (CH 4 ) emission and its relation with rumen digestion in dairy cows fed diets rich in 1 of the 2 carbohydrate sources, starch or sugar. The rations were based on late first-cut grass-clover silage supplemented with wheat (Wh), NaOH-treated wheat (Wh+NaOH), sugar beet molasses (Mo), or sugar beet molasses with addition of sodium bicarbonate (Mo+Bic). Wheat and molasses made up 35% of dry matter in the 2 diets with molasses and wheat, respectively. Four cows fitted with ruminal, duodenal, and ileal canulae were used in a 4 × 4 Latin square design. Nutrient digestibility was measured using chromium oxide and titanium oxide as flow markers, and emissions of CH 4 and hydrogen were measured via open-circuit indirect calorimetry on 4 consecutive days. Data were analyzed using PROC MIXED of SAS (version 9.4; SAS Institute Inc., Cary, NC) with treatment and period as fixed effects and cow as random effect. Furthermore, orthogonal contrasts were calculated. The cows produced 32.5, 33.6, 36.2, and 35.1 L of CH 4 /kg of dry matter intake (DMI) on diets Wh, Wh+NaOH, Mo, and Mo+Bic, respectively. The emission of CH 4 per day, per kilogram of DMI, and per kilogram of energy-corrected milk as well as daily hydrogen emission were higher on the Mo diet compared with the Wh diet. With the present inclusion of wheat and molasses in the diet, no effects of NaOH treatment of wheat or of sodium bicarbonate supplementation to the Mo diet could be demonstrated on CH 4 emission expressed per kilogram of DMI or per kilogram of energy-corrected milk. The duodenal flow of starch was higher when wheat was treated with NaOH. Under the conditions in the present experiment, ruminal NDF digestibility was not affected by carbohydrate source, NaOH treatment of wheat, or bicarbonate supplementation. Total volatile fatty acid concentration in the rumen and the proportions of acetate and propionate were not affected by carbohydrate source, NaOH treatment of wheat, or bicarbonate supplementation. Likewise, we could not show any influence of diet on microbial protein synthesis or efficiency of microbial protein synthesis expressed as grams of microbial protein synthesis per kilogram of true rumen-digested organic matter. We concluded that CH 4 emission was increased when wheat was replaced by molasses, whereas no effect of manipulating rumen fermentation by NaOH treatment of wheat or addition of bicarbonate to molasses could be found with a level of approximately 25% of dry matter from starch and sugar, respectively.

Protected or Unprotected Fat Addition for Feedlot Lambs: Feeding Behavior, Carcass Traits, and Meat Quality

“…Odd-and branched-chain fatty acids (OBCFA) are formed by ruminal bacteria from the elongation of propionate, valerate, valine, leucine, and isoleucine [55]. Animals fed a higher amount of NFC have a higher proportion of OBCFA precursors [56]. Dietary fat inclusion (WSB, CSFA, SO, and CG) were related to decreased levels of NFC in the diets, which explains the reason for the concentrations of FA C17:0 iso being higher with the NAF diet.…”

A Review: Plant Carbohydrate Types—The Potential Impact on Ruminant Methane Emissions

“…According to Nozière et al (120), the chemical treatment of grains can be used to prevent rumen acidosis by reducing the digestibility of the starch inside the rumen. Furthermore, introducing buffers (e.g., sodium bicarbonate or plant buffering capacity) to starch-based diets reduces the prevalence of rumen acidosis by stabilising rumen pH and improving feed digestion (121,122). emissions per unit of DM were numerically 10% lower for cows fed the Jerusalem artichoke tubers than cows fed wheat.…”

Methane Emissions Regulated by Microbial Community Response to the Addition of Monensin and Fumarate in Different Substrates

“…Enteric methane is formed during the microbial degradation of food in the rumen, and any variation in its production level relies on changes in the microbial ecosystem [29]. The diversity indexes of prokaryotic microbiota, with F as the substrate were significantly higher than V, and the microbial community structure (e.g., Euryarchaeota and Tenericutes) varied under the two substrates.…”