Crop byproducts supplemented in livestock feeds reduced greenhouse gas emissions.

Crop byproducts can be supplemented in livestock feeds to improve the utilization of resources and reduce greenhouse gas (GHG) emissions. We explored the mitigation potential of GHG emissions by supplementing crop byproducts in feeds based on a typical intensive dairy farm in China. Results showed that GHG emissions associated with production of forage were significantly decreased by 25.60 % when no GHG emissions were allocated to crop byproducts, and enteric methane emission was significantly decreased by 13.46 % on the basis of CO2 eq, g/kg fat and protein corrected milk. The supplementation did not affect lactation performance, rumen microbiota and microbial enzymes at the gene level. Metabolomics analysis revealed changes in amino acid catabolism of rumen fluid, which were probably responsible for more propionate production. In conclusion, supplementing crop byproducts in feeds can be a potential strategy to reduce GHG emissions of livestock.

Influence of Azadirachta indica and Cnidoscolus angustidens Dietary Extracts on Equine Fecal Greenhouse Gas Emissions.

The present study was conducted to investigate the aqueous extracts of Azadirachta indica (AZN), Cnidoscolus angustidens (CNA), and their combination (MIX) at dosages of 0-, 0.6-, 1.2-, and 1.8- mL for their ability to reduce greenhouse gases and fermentation profiles in an in vitro study using horse feces and a nutrient-dense diet (as substrate). The quantity of greenhouse gas and fermentation profiles were determined in in vitro incubation for 48 h. Extracts of AZN, CNA, and MIX reduced total gas production of the incubated and degraded substrates in a dose-dependent and time-dependent manner. Production of CH4 was reduced (P < .05) by 4.41% to 54.54% with the incubated substrates and by 1.16% to 61.82% with the degraded substrates. However, AZN and MIX reduced (P < .05) CO by 4.43% to 12.85% with the incubated substrates and by 0.70% to 16.78% with the degraded substrates. In like manner, the plant extracts and combination reduced (P < .05) H2S production in a dose-dependent and time-dependent manner by 18.37% to 67.35% with the incubated substrates and by 8.51% to 67.23% with the degraded substrates. Extracts maintained pH within the normal range, reduced dry matter digestibility and metabolizable energy, and improved (P < .05) concentration of short chain fatty acids. Overall, aqueous extracts of AZN and CNA and their combinations had a positive effect on reducing the greenhouse gas production with no deleterious effect on fecal horses' fermentation activities.

Anti-Methanogenic Traits of Safflower Oil Compounds Against Methyl-Coenzyme M Reductase Receptor in Equines: An In Silico Docking Analysis.

Greenhouse gases emission from livestock is the major concern for the ecosystem. Despite the lower contribution of non-ruminants towards greenhouse gas emission as compared to the ruminants, the emission of methane (CH4) gas from equines is expected to be increased in future due to its increasing population. Thus, it is essential to find or screen potential anti-methanogenic agent in a cost-effective and quicker manner. Considering this, the present investigation was aimed to analyze anti-methanogenic characteristic of bioactive compounds of safflower oil by targeting methanogenesis catalyzing enzyme (Methyl-coenzyme M reductase; MCR) via in silico tool. Initially, a total of 25 compounds associated with safflower oil were selected and their drug-likeness traits were predicted through Lipinski's rule of 5. Of 25 compounds, 9 compounds passed all the parameters of Lipinski's rule of five. These 9 ligands were further submitted for ADME traits analysis using Swiss ADME tool. Results revealed the absence of Lipinski's violation and approval of drug-likeness attributes of methyl tetradecanoate, 3-isopropyl-6-methylenecyclohex-1-ene, trans-2,4-decadienal, cis-6-nonenal, limonene, syringic acids, matairesinol, acacetin, and 2,5-octanedione. Molecular docking analysis was performed for analyzing the affinity between the selected 9 ligands and MCR receptor using FRED v3.2.0 from OpenEye Scientific Software and Discovery Studio client v16.1.0. Results showed maximum binding interaction of acacetin with MCR with the chemguass4 score of -13.35. Other ligands showed comparatively lower binding affinity in the order of matairesinol (-12.43) > methyl tetradecanoate (-9.25) > cis-6-nonenal (-7.88) > syringic acids (-7.73) > limonene (-7.18) > trans-2,4-decadienal (-7.07) > 3-isopropyl-6-methylenecyclohex-1-ene (-7.01) > 2,5-octanedione (-7.0.). In a nutshell, these identified compounds were observed as potential agents to reduce CH4 production from equines by targeting MCR. This in silico study emphasized the role of safflower-associated compounds in developing anti-methanogenic drug for equines in future.

Effects of protein supplementation to steers consuming low-quality forages on greenhouse gas emissions.

Providing supplements that enhance the efficiency of feed utilization can reduce methane (CH4) emissions from ruminants. Protein supplementation is widely used to increase intake and digestion of low-quality forages, yet little is known about its impact on CH4 emissions. British-cross steers (n = 23; initial body weight [BW] = 344 ± 33.9 kg) were used in a three-period crossover design to evaluate the effect of protein supplementation to beef cattle consuming low-quality forage on ruminal CH4, metabolic carbon dioxide (CO2) emissions, forage intake, and ruminal fermentation. Steers individually had ad libitum access to low-quality bluestem hay (4.6% crude protein [CP]) and were provided supplemental protein based on (dry matter basis): cottonseed meal (CSM; 0.29% of BW daily; 391 g/d CP), dried distillers grains with solubles (DDGS; 0.41% of BW daily 563 g/d CP), or none (CON). Urea was added to DDGS to match rumen degradable protein provided by CSM. Ruminal CH4 and metabolic CO2 fluxes were obtained 2.4 ± 0.4 times per steer daily using an automated open-circuit gas quantification system (GreenFeed emission monitoring system; C-Lock Inc., Rapid City, SD). Forage intake increased (P < 0.01) with protein supplementation; however, no difference in forage intake (P = 0.14) was observed between CSM and DDGS treatments. Flux of CO2 (g/d) was greater (P < 0.01) for steers fed CSM and DDGS than for steers fed CON. Steers supplemented with CSM had greater (P < 0.01) CH4 emissions (211 g/d) than DDGS (197 g/d) both of which were greater (P < 0.01) than CON (175 g/d). Methane emissions as a proportion of gross energy intake (GEI) were lowest (P < 0.01) for DDGS (7.66%), intermediate for CSM (8.46%) steers, and greatest for CON (10.53%). Steers fed DDGS also had the lowest (P < 0.01) ruminal acetate:propionate ratio (3.60), whereas CSM (4.89) was intermediate, and CON (5.64) steers were greatest. This study suggests that the common practice of supplementing protein to cattle consuming low-quality forage decreases greenhouse gas emissions per unit of GEI.

Links between the rumen microbiota, methane emissions and feed efficiency of finishing steers offered dietary lipid and nitrate supplementation.

Ruminant methane production is a significant energy loss to the animal and major contributor to global greenhouse gas emissions. However, it also seems necessary for effective rumen function, so studies of anti-methanogenic treatments must also consider implications for feed efficiency. Between-animal variation in feed efficiency represents an alternative approach to reducing overall methane emissions intensity. Here we assess the effects of dietary additives designed to reduce methane emissions on the rumen microbiota, and explore relationships with feed efficiency within dietary treatment groups. Seventy-nine finishing steers were offered one of four diets (a forage/concentrate mixture supplemented with nitrate (NIT), lipid (MDDG) or a combination (COMB) compared to the control (CTL)). Rumen fluid samples were collected at the end of a 56 d feed efficiency measurement period. DNA was extracted, multiplexed 16s rRNA libraries sequenced (Illumina MiSeq) and taxonomic profiles were generated. The effect of dietary treatments and feed efficiency (within treatment groups) was conducted both overall (using non-metric multidimensional scaling (NMDS) and diversity indexes) and for individual taxa. Diet affected overall microbial populations but no overall difference in beta-diversity was observed. The relative abundance of Methanobacteriales (Methanobrevibacter and Methanosphaera) increased in MDDG relative to CTL, whilst VadinCA11 (Methanomassiliicoccales) was decreased. Trimethylamine precursors from rapeseed meal (only present in CTL) probably explain the differences in relative abundance of Methanomassiliicoccales. There were no differences in Shannon indexes between nominal low or high feed efficiency groups (expressed as feed conversion ratio or residual feed intake) within treatment groups. Relationships between the relative abundance of individual taxa and feed efficiency measures were observed, but were not consistent across dietary treatments.

Measured greenhouse gas budgets challenge emission savings from palm-oil biodiesel.

The potential of palm-oil biofuels to reduce greenhouse gas (GHG) emissions compared with fossil fuels is increasingly questioned. So far, no measurement-based GHG budgets were available, and plantation age was ignored in Life Cycle Analyses (LCA). Here, we conduct LCA based on measured CO2, CH4 and N2O fluxes in young and mature Indonesian oil palm plantations. CO2 dominates the on-site GHG budgets. The young plantation is a carbon source (1012 ± 51 gC m-2 yr-1), the mature plantation a sink (-754 ± 38 gC m-2 yr-1). LCA considering the measured fluxes shows higher GHG emissions for palm-oil biodiesel than traditional LCA assuming carbon neutrality. Plantation rotation-cycle extension and earlier-yielding varieties potentially decrease GHG emissions. Due to the high emissions associated with forest conversion to oil palm, our results indicate that only biodiesel from second rotation-cycle plantations or plantations established on degraded land has the potential for pronounced GHG emission savings.

Associative effects of wet distiller's grains plus solubles and tannin-rich peanut skin supplementation on in vitro rumen fermentation, greenhouse gas emissions, and microbial changes1.

Two sets of in vitro rumen fermentation experiments were conducted to determine effects of diets that included wet distiller's grains plus solubles (WDGS) and tannin-rich peanut skin (PS) on the in vitro digestibility, greenhouse gas (GHG) and other gas emissions, fermentation rate, and microbial changes. The objectives were to assess associative effects of various levels of PS or WDGS on the in vitro digestibility, GHG and other gas emissions, fermentation rate, and microbial changes in the rumen. All gases were collected using an ANKOM Gas Production system for methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), and hydrogen sulfide (H2S) analyses. Cumulative ruminal gas production was determined using 250 mL ANKOM sampling bottles containing 50 mL of ruminal fluid (pH 5.8), 40 mL of artificial saliva (pH 6.8), and 6 g of mixed diets after a maximum of 24 h of incubation. Fermenters were flushed with CO2 gas and held at 39 °C in a shaking incubator for 24 h. Triplicate quantitative real-time polymerase chain reaction (qPCR) analyses were conducted to determine microbial diversity. When WDGS was supplied in the diet, in the absence of PS, cumulative CH4 production increased (P < 0.05) with 40% WDGS. In the presence of PS, production of CH4 was reduced but the reduction was less at 40% WDGS. In the presence of PS, ruminal lactate, succinate, and acetate/propionate (A/P) ratio tended to be less with a WDGS interaction (P < 0.01). In the presence of PS and with 40% WDGS, average populations of Bacteroidetes, total methanogens, Methanobrevibacter sp. AbM4, and total protozoa were less. The population of total methanogens (R2 = 0.57; P < 0.01), Firmicutes (R2 = 0.46: P < 0.05), and Firmicutes/Bacteroidetes (F/B) ratio (R2 = 0.46; P < 0.03) were strongly correlated with ruminal CH4 production. Therefore, there was an associative effect of tannin-rich PS and WDGS, which suppressed methanogenesis both directly and indirectly by modifying populations of ruminal methanogens.

Reducing ammonia and greenhouse gas emission with adding high levels of superphosphate fertilizer during composting.

Previous studies revealed that superphosphate fertilizer (SSP) as an additive in compost can reduce the nitrogen loss and improve the effectiveness of phosphorus during composting. However, few studies have explored the influence of adding SSP with high levels on ammonia and greenhouse gas emission and the suitable amount for SSP addition according to a combined assessment of the composting process and product. The present study aimed to evaluate the impact of SSP with high additive amounts on NH3, CO2, CH4, and N2O emission and organic carbon loss. All piles were mixtures of pig manure and cornstalks with different levels of SSP addition including 10%, 14%, 18%, 22%, 26%, and 30% dry weight basis of raw materials. Compared with the control without SSP, the amount of NH3 cumulative emissions was decreased by 23.8-48.1% for the treatments with 10-30% SSP addition, and the emission of greenhouse gas including CO2, CH4, and N2O by 20.9-35.5% (CO2 equivalent) was reduced by 20.9-35.5%. Adding SSP with the amount exceeding 14% to compost could reduce CO2 emissions by 32.0-38.4% and more than 30% carbon loss at the end of composting but exceeding 26% had an adverse impact on maturity of the composts. Therefore, considering the maturity and safety of compost and gas emission reduction, 14-26% SSP was the optimum amount for composting addition, which is an effective and economical way to increase the nutrient level of carbon, nitrogen, and phosphorus in compost and reduce environmental risks.

China's livestock transition: Driving forces, impacts, and consequences.

China's livestock industry has experienced a vast transition during the last three decades, with profound effects on domestic and global food provision, resource use, nitrogen and phosphorus losses, and greenhouse gas (GHG) emissions. We provide a comprehensive analysis of the driving forces around this transition and its national and global consequences. The number of livestock units (LUs) tripled in China in less than 30 years, mainly through the growth of landless industrial livestock production systems and the increase in monogastric livestock (from 62 to 74% of total LUs). Changes were fueled through increases in demand as well as, supply of new breeds, new technology, and government support. Production of animal source protein increased 4.9 times, nitrogen use efficiency at herd level tripled, and average feed use and GHG emissions per gram protein produced decreased by a factor of 2 between 1980 and 2010. In the same period, animal feed imports have increased 49 times, total ammonia and GHG emissions to the atmosphere doubled, and nitrogen losses to watercourses tripled. As a consequence, China's livestock transition has significant global impact. Forecasts for 2050, using the Shared Socio-economic Pathways scenarios, indicate major further changes in livestock production and impacts. On the basis of these possible trajectories, we suggest an alternative transition, which should be implemented by government, processing industries, consumers, and retailers. This new transition is targeted to increase production efficiency and environmental performance at system level, with coupling of crop-livestock production, whole chain manure management, and spatial planning as major components.

Performance, profitability and greenhouse gas emissions of alternative finishing strategies for Holstein-Friesian bulls and steers.

Modifying finishing strategies within established production systems has the potential to increase beef output and farm profit while reducing greenhouse gas (GHG) emissions. Thus, the objectives of this study were to investigate the effects of finishing duration on animal performance of Holstein-Friesian (HF) bulls and steers and evaluate the profitability and GHG emissions of these finishing strategies. A total of 90 HF calves were assigned to a complete randomised block design; three bull and three steer finishing strategies. Calves were rotationally grazed in a paddock system for the first season at pasture, housed and offered grass silage ad libitum plus 1.5 kg DM of concentrate per head daily for the first winter and returned to pasture for a second season. Bulls were slaughtered at 19 months of age and either finished indoors on concentrates ad libitum for 100 days (19AL), finished at pasture supplemented with 5 kg DM of concentrate per head daily for 100 (19SP) or 150 days (19LP). Steers were slaughtered at 21 months of age and finished at pasture, supplemented with 5 kg DM of concentrate per head daily for 60 (21SP) and 110 days (21LP) or slaughtered at 24 months of age and finished indoors over the second winter on grass silage ad libitum plus 5 kg DM of concentrate per head daily (24MO). The Grange Dairy Beef Systems Model and the Beef Systems Greenhouse Gas Emissions Model were used to evaluate profitability and GHG emissions, respectively. Average daily gain during the finishing period (P<0.001), live weight at slaughter (P<0.01), carcass weight (P<0.05) and fat score (P<0.001) were greater for 19AL than 19SP and 19LP, respectively. Similarly, concentrate dry matter intake was greater for 19AL than 19SP; 19LP was intermediate (P<0.001). Live weight at slaughter (P<0.001), carcass weight (P<0.001), conformation score (P<0.05) and fat score (P<0.001) were greater for 24MO than 21SP and 21LP, respectively. During the finishing period concentrate dry matter intake was greater for 21LP than 21SP with 24MO intermediate; 542, 283 and 436 kg DM, respectively. Although pasture-based finishing strategies had lower gross output values, concentrate feed costs were also reduced thus net margin was greater than indoor finishing strategies. Reducing concentrate input increased GHG emissions for bulls and steers slaughtered at the same age, respectively. Although prolonging the finishing duration reduced GHG emissions for bull and steer production systems, finishing bulls and steers over a longer period at pasture did not enhance animal performance and profit.

Influence of feeding supplements of almond hulls and ensiled citrus pulp on the milk production, milk composition, and methane emissions of dairy cows.

Almond hulls and citrus pulp have been fed to dairy cows with variable responses for milk production, but no information exists on their effect on enteric methane emissions. This experiment examined the effects of dietary supplementation with either almond hulls or ensiled citrus pulp on the milk yield, milk composition, and enteric methane emissions of dairy cows. Thirty-two Holstein dairy cows in mid lactation were offered 1 of 3 diets over a 28-d experiment. Twelve cows received a control (CON) diet, 10 cows a diet containing almond hulls (ALH), and 10 cows a diet containing ensiled citrus pulp (CIT). All cows were offered 6.0 kg of dry matter (DM)/d of crushed corn, 2.0 kg of DM/d of cold-pressed canola, and 0.2 kg of DM/d of a mineral mix. In addition, cows fed the CON diet were offered 14.5 kg of DM/d of alfalfa cubes; cows fed the ALH diet were offered 10.5 kg of DM/d of alfalfa cubes and 4.0 kg of DM/d of almond hulls; and cows on the CIT diet were offered 11.5 kg of DM/d of alfalfa cubes and 3.0 kg of DM/d of ensiled citrus pulp. Milk yield was measured daily and milk composition was measured on 4 d of each week. Individual cow methane emissions were measured by a sulfur hexafluoride tracer technique on d 24 to 28 of the experiment. The mean milk yield of cows fed the CON diet (27.4 kg/d) was greater than the mean milk yield of cows fed the ALH diet (24.6 kg/cow per day), whereas the mean milk yield of cows fed the CIT diet (26.2 kg/cow per day) was not different from the mean milk yield from cows fed the other 2 diets. Dietary treatment did not influence the concentrations of milk fat, protein, and lactose or fat yields, but the mean protein yield from cows fed the CON diet (0.87 kg/d) was greater than that from cows fed the ALH diet (0.78 kg/d) but not different to those fed the CIT diet (0.85 kg/d). In general, we found no differences in the proportion of individual fatty acids in milk. The mean pH of ruminal fluid from cows offered the CON diet was not different to the pH in the ruminal fluids of cows offered the ALH or the CIT diets. The mean methane emissions (g/d) and yields (g/kg of DM intake) were not influenced by dietary treatment. These findings indicate that, although almond hulls and ensiled citrus pulp can be used as a low-cost feed supplement, almond hulls did negatively affect milk production and neither inhibited enteric methane emissions.