Enteric methane emissions by young Brahman bulls grazing tropical pastures at different rainfall seasons in the Peruvian jungle.

Enteric methane emissions from lactating dairy cows grazing cultivated and native pastures in the high Andes of Peru

Enteric and manure-derived methane emissions and biogas yield of slurry from dairy cows fed grass silage or maize silage with and without supplementation of rapeseed

From 1990 to 1992, diet selection and nutrient intake of Zebu cattle grazing Sahelian pasture were studied in Central Mali. Forty-five intact males and 12 oesophageally fistulated animals were separated into three groups of 15 intact and 4 fistulated animals. The control group (C) grazed natural pasture only, while the moderately supplemented group (M) additionally received 0·8–1·5 kg OM/day of crop by-products during the dry season (November–June) and the first month of the rainy season. The third group (H) was highly supplemented with 1·2–2·7 kg OM/day in the dry season and 0·8–1·2 kg OM/day in the rainy season. Oesophageal extrusa was collected during 5 consecutive days at intervals of 4–5 weeks. Samples were analysed for contents of organic matter (OM), crude protein (CP) and neutral detergent fibre (NDF). Digestible organic matter (DOM) and metabolizable energy content (ME) were calculated from in vitro gas release. Intake of organic matter (IOM) of the fistulated animals was determined from faecal organic matter excretion (FOM) and extrusa DOM content. Intake of CP (ICP) and ME (IME) were calculated from IOM and the respective nutrient contents of extrusa samples.Extrusa CP, DOM and ME contents did not differ significantly between the three groups either in the dry or in the rainy season. The CP content was c. 230 and c. 197 g/kg OM during the rainy season, and declined to values [les ]70 and [les ]95 g CP/kg OM at the end of the dry season of 1990 and 1991, respectively. Average DOM and ME contents were c. 668 g DOM and c. 9·9 MJ ME/kg OM during rainy seasons. At the end of the dry seasons, these values decreased to <550 g DOM and <8·0 MJ ME/kg OM. Per kg of metabolic body mass, IOM of group C was c. 89 g/day during the early dry season. It was accompanied by a daily ICP of 8–10 g and by an IME of 691–765 kJ/day. Due to a higher nutrient content in the selected diet, energy intake was slightly increased and protein intake was significantly higher during the rainy than during the dry season, although IOM was only 77–81 g/day. At the end of the dry season, unsupplemented animals ingested <70 g IOM/day and the concomitant CP and ME intake were <6 g CP/day and <500 kJ ME/day, respectively. Feed intake from pasture was stimulated by a moderate supplementation, but reduced by a high supplementation. The results indicate that on slightly degraded Sahelian rangeland, the nutrient intake of cattle is in the first place limited by biomass availability and only secondly by the quality of the vegetation.

Development of mathematical models to predict enteric methane emission by cattle in Latin America

Effects of feed intake on enteric methane emissions from sheep fed fresh white clover (Trifolium repens) and perennial ryegrass (Lolium perenne) forages

Simple SummaryDried distillers’ grains (DDG), a co-product of ethanol production from corn, is gaining attention for its efficiency in ruminant nutrition, as it meets both the energy and protein demands of livestock and is less costly than the popular alternatives. The aim of this study was to evaluate the effect of replacing cottonseed meal with DDG at two levels (50 and 100%) on young Nellore bulls grazing Marandu grass in the rainy season, focusing on ruminal parameters, animal performance, and methane (CH4) emissions. When replacing 50% of cottonseed meal with DDG, animals presented higher intakes of dry matter, organic matter, forage, and digestible organic matter, compared to 100% DDG. Ruminal parameters, including pH, acetate, and acetate: propionate, were higher when animals received only mineral supplementation. Animals supplemented with concentrate (cottonseed meal and/or DDG) presented greater daily weight gain and final body weight than the animals consuming mineral supplementation. Replacing cottonseed meal with DDG does not cause great variations in ruminal parameters, animal performance, and enteric CH4 emissions in grazing Nellore cattle during the rearing phase in the wet season. However, supplementation of 0.3% body weight with the concentrate can improve the productive performance of grazing animals. Both protein sources, DDG or cottonseed meal, can be used to intensify grazing beef cattle production.Two experiments were conducted to evaluate the effect of replacing cottonseed meal with DDG on ruminal parameters, methane (CH4) emissions (Experiment 1), and animal performance (Experiment 2) of young Nellore bulls grazing Marandu grass during the rainy season. Four supplementation strategies were used in both experiments: (1) Mineral supplementation (MS); (2) conventional multiple supplement (energy/protein) with cottonseed meal and citrus pulp (CMS); (3) CMS with 50% cottonseed meal replaced by DDG (50DDG); and (4) CMS with 100% cottonseed meal replaced by DDG (100DDG). The 50DDG condition resulted in greater intake of dry matter (p = 0.033), organic matter (OM) (p = 0.050), forage (p = 0.035), and digestible OM (p = 0.031) than 100DDG. The supplemented animals presented greater final body weight (BW) and average daily gain than the animals consuming MS (p = 0.011), and lower pH, acetate, and acetate:propionate (p < 0.05). However, the treatments had no influence on stocking rate, gain per area, and enteric CH4 emissions (p > 0.05). Replacing cottonseed meal with DDG does not result in great variations in ruminal parameters, animal performance, and enteric CH4 emissions of grazing Nellore cattle during the rearing phase in the wet season. Both protein sources in 0.3% BW supplementation can be used to intensify beef cattle production in pastures.

Performance and enteric methane emission of growing beef bulls from different genetic groups subjected to two supplementation strategies grazing tropical grass in the rainy season

Diet supplementation with a mixture of essential oils: Effects on enteric methane emissions, apparent total-tract nutrient digestibility, nitrogen utilization, and lactational performance.

Lactational performance and enteric methane emissions in dairy cows fed high-oil oats, cold-pressed rapeseed cake, and 3-nitrooxypropanol in a grass silage-based diet.

Enteric methane emission from growing yak calves aged 8–16 months: Predictive equations and comparison with other ruminants

Simple SummaryNumerous enteric methane (CH4) mitigation opportunities exist to reduce enteric CH4 and other greenhouse gas emissions per unit of product from ruminants. Research over the past century in genetics, animal health, microbiology, nutrition, and physiology has led to improvements in dairy and beef cattle production. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4 emissions per unit of products (energy-corrected milk, milk yield, average daily gain, dry matter intake, and gross energy intake) from dairy and beef cattle on a quantitative basis and in a sustained manner, and to integrate approaches in feeding, rumen fermentation profiles, and rumen microbiota changes to emphasize the understanding of these relationships between enteric CH4 emissions and animal productivities.Enteric methane (CH4) emissions produced by microbial fermentation in the rumen resulting in the emission of greenhouse gases (GHG) into the atmosphere. The GHG emissions reduction from the livestock industry can be attained by increasing production efficiency and improving feed efficiency, by lowering the emission intensity of production, or by combining the two. In this work, information was compiled from peer-reviewed studies to analyze CH4 emissions calculated per unit of milk production, energy-corrected milk (ECM), average daily gain (ADG), dry matter intake (DMI), and gross energy intake (GEI), and related emissions to rumen fermentation profiles (volatile fatty acids [VFA], hydrogen [H2]) and microflora activities in the rumen of beef and dairy cattle. For dairy cattle, there was a positive correlation (p < 0.001) between CH4 emissions and DMI (R2 = 0.44), milk production (R2 = 0.37; p < 0.001), ECM (R2 = 0.46), GEI (R2 = 0.50), and acetate/propionate (A/P) ratio (R2 = 0.45). For beef cattle, CH4 emissions were positively correlated (p < 0.05–0.001) with DMI (R2 = 0.37) and GEI (R2 = 0.74). Additionally, the ADG (R2 = 0.19; p < 0.01) and A/P ratio (R2 = 0.15; p < 0.05) were significantly associated with CH4 emission in beef steers. This information may lead to cost-effective methods to reduce enteric CH4 production from cattle. We conclude that enteric CH4 emissions per unit of ECM, GEI, and ADG, as well as rumen fermentation profiles, show great potential for estimating enteric CH4 emissions.

Livestock-forestry (LF) systems enhance the delivery of ecosystem services and sustainability by providing shade, increasing diversity, and improving carbon sequestration. Despite these benefits, more evidence is needed to establish LF systems as a viable alternative for reducing enteric CH4 emissions and improving thermal comfort in beef cattle production. We aimed to evaluate the impact of the forestry component into a forage-based livestock system on animal performance, thermal comfort, and its consequences on enteric CH4 emissions. The experimental design was a randomized complete block with two systems: livestock (L) and LF, each with four replicates. During both seasons, microclimate variables such as relative humidity, photosynthetically active radiation, black globe temperature, and black globe temperature-humidity index were greater in the L system. Plant-part and chemical compositions did not differ between the systems, except for a 10% greater leaf proportion in LF during the rainy season. During the dry season, the LF system showed a 47% greater total gain per ha and 33% greater stocking rate. There was no system effect on CH4 production (g/day). However, in the dry season, LF presented greater CH4 emissions per area. These results indicate that integrating trees into forage-based livestock systems can improve thermal comfort and animal productivity without increasing individual CH4 emission, enhancing long-term productivity and sustainability.

Effects of plant-bound condensed tannin (CT)-containing sainfoin vs. CT-free alfalfa (or low-CT alfalfa-sainfoin mixture), plant stage of maturity, and their interaction on enteric methane (CH4) emissions, diet digestibility, and N excretion were studied, using 8 ruminally cannulated beef heifers in 2 sequential short-term experiments (Exp. 1 and 2). In Exp. 1, first growth legumes were harvested daily and offered fresh to heifers. Heifers were assigned to 100% sainfoin or 80% alfalfa:20% sainfoin (as-fed basis). Responses were measured at early (late vegetative to early bud; stage 2 to 3) and late (early flower; stage 5) stage of maturity. In Exp. 2, the same legumes were harvested from second growth (late bud; stage 4) and offered to heifers as hay; 100% sainfoin or 100% alfalfa. In both experiments, heifers were fed once daily at 1× maintenance. When fed as fresh forage (Exp. 1), sainfoin, compared with the alfalfa-sainfoin blend, had greater digestibility of OM (74.7 vs. 70.9%; P = 0.02), yet tended to have lower CP digestibility (73.2 vs. 77.1%; P = 0.059). There was no difference between fresh legumes for CH4 emissions [25.9 g/kg DMI ± 4.02 SE; 8.5% of gross energy intake (GEI) ± 1.26 SE; or 36.8 g/kg digested OM ± 1.75 SE]. The fresh legumes were more digestible at early, rather than at late, maturity and, consequently, enteric CH4 (27.4 vs. 24.4 g/kg DMI; P < 0.004; 8.9 vs. 8.1% GEI; P < 0.008) was greater at early, rather than at later, growth. When fed as hay (Exp. 2), sainfoin, compared with alfalfa, had greater digestibility of OM (60.5 vs. 50.3%; P = 0.007), lower digestibility of CP (64.2 vs. 68.8%; P = 0.004), yet there was no difference between the legume hays for CH4 emissions (22.4 g/kg DMI ± 1.29 SD and 7.1% GEI ± 0.40 SD). However, on the basis of OM digested, CH4 emissions were lower for sainfoin than alfalfa hay (44.3 vs. 59.0 g/kg; P = 0.008). Percentage of total N excretion in urine was less for sainfoin compared with alfalfa, both for fresh legumes in Exp. 1 (74 vs. 78%; P = 0.017) or hay in Exp. 2 (64 vs. 72%; P < 0.001), and increasing maturity lowered urinary N excretion. In conclusion, feeding CT-containing sainfoin partially shifted N excretion from urine to feces, but it had little impact on enteric CH4 emissions from beef cattle fed at maintenance as compared with feeding either 80% alfalfa:20% sainfoin (fresh forages) or 100% alfalfa (hay). Feeding fresh legumes harvested between the late vegetative to early bud stage, compared with harvested at the early flower stage, increased N excreted in urine as well as enteric CH4 emissions from beef cattle fed at maintenance.

Methane emissions (CH4) from enteric fermentation represent an energy loss to the animal ranging from 2% to 12% of gross energy (GE) intake; therefore, the challenge is to develop diets and handling strategies to mitigate CH4 emissions. This study tested the hypothesis that fat supplementation as a source of energy could reduce CH4 emissions without decrease animal production, independently of the starch level utilised. Thus, the goal of this study was to assess the combined effects of high- or low-starch supplements with or without a source of oil (soybean grain) on intake, digestibility, performance, and CH4 emissions of finishing Nellore bulls [n = 44; initial bodyweight (BW) = 414 ± 12 kg; age of 20 months] grazing on Brachiaria brizantha cv. Xaraés during the dry season. No interactions between starch level and oil source (soybean grain) supplementation with respect to intake of dry matter (DM), forage DM, supplement DM, organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), ether extract (EE), or GE were found. However, there was an effect of starch and oil source on intake of EE. There were no interactions between starch level and oil source supplementation with respect to digestibility of DM, OM, NDF, CP, EE, or digestibility energy. Irrespective of the starch level utilised, the addition of soybean grain (oil source) decreased the digestibility of NDF and increased the digestibility of EE. In relation to animal performance, there were no interactions between starch level and oil regarding initial BW, final BW, average daily gain (ADG), gain efficiency, hot carcass weight, dressing, carcass gain, fat depth, or longissimus muscle area. However, the addition of soybean grain (oil source) increased the fat depth independently of the starch level used. There was no interaction between starch-based supplementation level and oil source on CH4 emissions when expressed in g/day, g/kg DM intake, g/kg OM intake, g/kg NDF intake, % of GE intake, g/g EE intake, g/kg ADG, or g/kg of carcass gain. Therefore, the addition of soybean grain (oil source) in supplements, independent of starch level used, was associated with reduced CH4 emissions expressed in g/day. Additionally, soybean grain (oil source) decreased enteric CH4 emissions relative to GE and EE intake and ADG for animals fed high- or low-starch supplements. Soybean grain supplementation is effective at reducing enteric CH4 emissions from Nellore bulls grazing on tropical pasture.

An experiment was conducted to examine how dietary interventions reducing enteric methane (CH4) emissions influence manure CH4 emissions in biogas production (as biochemical methane potential (BMP)) or under static conditions mimicking natural manure storage conditions. Experimental treatments consisted of a factorial arrangement of high (HF: 0.65) or low (LF: 0.35) levels of forage and 0 or 50 g of rapeseed oil per kg of diet dry matter. Oil supplementation reduced daily enteric CH4 emissions, especially in the HF diet, by 20%. Greater dietary concentrate proportion reduced CH4 yield and intensity (6 and 12%, respectively) and decreased pH, increased total volatile fatty acids, and molar proportions of butyrate and valerate in feces incubated under static conditions. Oil supplementation increased daily BMP and BMP calculated per unit of organic matter (OM) (17 and 15%, respectively). Increased dietary concentrate had no impact on daily BMP and BMP per unit of OM, whereas it reduced daily CH4 production by 89% and CH4 per unit of OM by 91% under static conditions. Dietary oil supplementation tended to decrease fecal CH4 production per unit of digestible OM (23%) under static conditions. Diets had no impact on the alpha diversity of ruminal prokaryotes. After incubation, the fecal prokaryote community was significantly less diverse. Diets had no effect on alpha diversity in the BMP experiment, but static trial fecal samples originating from the HF diet showed significantly lower diversity compared with the LF diet. Overall, the tested dietary interventions reduced enteric CH4 emissions and reduced or tended to reduce manure CH4 emissions under static conditions, indicating a lack of trade-off between enteric and manure CH4 emissions. The potential for increasing CH4 yields in biogas industries due to dietary interventions could lead to a sustainable synergy between farms and industry.