Intake, digestibility, growth performance, and enteric methane emission of Brazilian semiarid non-descript breed goats fed diets with different forage to concentrate ratios

Impact of diversified grazing systems on milk production, nutrient use and enteric methane emissions in dual-purpose cows

This study evaluated three continuous grazing systems: Brachiaria Brizantha, Clitoria ternatea and naturalized pastures, complemented with commercial concentrate and C. ternatea silage on milk yield, nutrient use and enteric methane (CH4) emissions. Nine multiparous cows of local Zebu breeds, with an average weight of 448 ± 87 kg, were used. The chemical composition of the food was determined. Live weight, milk production, and quality were assessed. Furthermore, serum urea, urea nitrogen, creatinine and glucose in blood were monitored, and nitrogen use efficiency were calculated. Enteric methane (CH4) emissions were estimated using Tier-2 methodology. A 3 × 3 latin square experimental design was applied. The grazing systems of B. brizantha and C. ternatea had the greater live weights of 465.8 and 453.3 kg/cow, although the latter is similar to naturalized pasture. Milk production and quality were not affected by grazing system, with the exception of the non-fat solids, where the C. ternatea system was lower (102.2 g/kg) than the other grazing systems. The crude protein and N intake, and N excretion in feces and urine were lower in naturalized pasture systems (1139.0 g/day). N outputs in milk was high in the C. ternatea system (56.3 g/cow/day). The naturalized pastures systems showed the better feed use efficiency (25.7%) compared to others. Serum urea and blood urea nitrogen were greater in B. brizantha followed by C. ternatea. Enteric CH4 emissions were indifferent among grazing systems when expressed as a percentage of greenhouse gases (7.1%). In conclusion, the grazing C. ternatea supplemented with commercial concentrate and C. ternatea silage maintains milk production and quality, reduced cow/day emissions (by 2.5%) and lowered energy losses as methane.

Quantifying the Impact of Different Dietary Rumen Modulating Strategies on Enteric Methane Emission and Productivity in Ruminant Livestock: A Meta-Analysis

A meta-analysis was conducted with an aim to quantify the beneficial effects of nine different dietary rumen modulating strategies which includes: the use of plant-based bioactive compounds (saponin, tannins, oils, and ether extract), feed additives (nitrate, biochar, seaweed, and 3-nitroxy propanol), and diet manipulation (concentrate feeding) on rumen fermentation, enteric methane (CH4) production (g/day), CH4 yield (g/kg dry matter intake) and CH4 emission intensity (g/kg meat or milk), and production performance parameters (the average daily gain, milk yield and milk quality) of ruminant livestock. The dataset was constructed by compiling global data from 110 refereed publications on in vivo studies conducted in ruminants from 2005 to 2023 and anlayzed using a meta-analytical approach.. Of these dietary rumen manipulation strategies, saponin and biochar reduced CH4 production on average by 21%. Equally, CH4 yield was reduced by 15% on average in response to nitrate, oils, and 3-nitroxy propanol (3-NOP). In dairy ruminants, nitrate, oils, and 3-NOP reduced the intensity of CH4 emission (CH4 in g/kg milk) on average by 28.7%. Tannins and 3-NOP increased on average ruminal propionate and butyrate while reducing the acetate:propionate (A:P) ratio by 12%, 13.5% and 13%, respectively. Oils increased propionate by 2% while reducing butyrate and the A:P ratio by 2.9% and 3.8%, respectively. Use of 3-NOP increased the production of milk fat (g/kg DMI) by 15% whereas oils improved the yield of milk fat and protein (kg/d) by 16% and 20%, respectively. On the other hand, concentrate feeding improved dry matter intake and milk yield (g/kg DMI) by 23.4% and 19%, respectively. However, feed efficiency was not affected by any of the dietary rumen modulating strategies. Generally, the use of nitrate, saponin, oils, biochar and 3-NOP were effective as CH4 mitigating strategies, and specifically oils and 3-NOP provided a co-benefit of improving production parameters in ruminant livestock. Equally concentrate feeding improved production parameters in ruminant livestock without any significant effect on enteric methane emission. Therefore, it is advisable to refine further these strategies through life cycle assessment or modelling approaches to accurately capture their influence on farm-scale production, profitability and net greenhouse gas emissions. The adoption of the most viable, region-specific strategies should be based on factors such as the availability and cost of the strategy in the region, the specific goals to be achieved, and the cost-benefit ratio associated with implementing these strategies in ruminant livestock production systems.

Effects of Dietary Nonfibrous Carbohydrate/Neutral Detergent Fiber Ratio on Methanogenic Archaea and Cellulose-Degrading Bacteria in the Rumen of Karakul Sheep: a 16S rRNA Gene Sequencing Study

The study was conducted to investigate the effects of dietary nonfibrous carbohydrate (NFC)/neutral detergent fiber (NDF) ratio on methanogenic archaea and cellulose-degrading bacteria in Karakul sheep by 16S rRNA gene sequencing. Twelve Karakul sheep were randomly divided into four groups, each group with three replicates, and they were fed with four dietary NFC/NDF ratios at 0.54, 0.96, 1.37, and 1.90 as groups 1, 2, 3, and 4, respectively. The experiment lasted for four periods: I (1 to 18 days), II (19 to 36 days), III (37 to 54 days), and IV (55 to 72 days); during each period, rumen contents were collected before morning feeding to investigate on methanogenic archaea and cellulose-degrading bacteria. The results showed that with an increase in dietary NFC/NDF ratio, the number of rumen archaea operational taxonomic units and the diversity of archaea decrease. The most dominant methanogens did not change with dietary NFC/NDF ratio and prolongation of experimental periods. Methanobrevibacter was the most dominant genus. At the species level, the relative abundance of Methanobrevibacter ruminantium first increased and then decreased when the NFC/NDF ratio increased. When the dietary NFC/NDF ratio was 0.96, the structure of archaea was largely changed, and the relative abundance of Fibrobacter sp. strain UWCM, Ruminococcus flavefaciens, and Ruminococcus albus were the highest. When the dietary NFC/NDF ratio was 1.37, the relative abundance of Butyrivibrio fibrisolvens was higher than for other groups. Based on all the data, we concluded that a dietary NFC/NDF ratio of ca. 0.96 to 1.37 was a suitable ratio to support optimal sheep production. IMPORTANCE CH₄ produced by ruminants aggravates the greenhouse effect and cause wastage of feed energy, and CH₄ emissions are related to methanogens. According to the current literature, there is a symbiotic relationship between methanogens and cellulolytic bacteria, so reducing methane will inevitably affect the degradation of fiber materials. This experiment used 16S rRNA gene high-throughput sequencing technology to explore the balance relationship between methanogens and cellulolytic bacteria for the first time through a long-term feeding period. The findings provide fundamental data, supporting for the diet structures with potential to reduce CH₄ emission.

Changes in the Metagenome-Encoded CAZymes of the Rumen Microbiome Are Linked to Feed-Induced Reductions in Methane Emission From Holstein Cows

Enteric methane (CH4) emission from cattle is strongly linked to the feeding regime and the rumen microbial community structure. Here, we report that feed-induced CH4-reducing effects correlate with specific alterations in the profile of the microbiome-encoded carbohydrate-active enzymes predicted from the rumen fluid metagenome. Rumen microbiome samples were obtained by mouth-tube sampling from 12 lactating Holstein cows after 3-4 weeks of feeding with three different concentrate-to-forage-ratio diets, i.e., standard, high, and extremely high levels of concentrate (4 cows per group; constant dry matter intake in the three groups). Increased inclusion of concentrate involved increased starch levels in the diet at the expense of fiber. The extreme diet resulted in 48% reduction of the CH4 emission per kg dry matter intake compared to the standard diet. From metagenome sequencing of the rumen fluid samples from each cow, 561 different microbial strains (bins) could be derived from analysis of 260 billion DNA base pairs. In the cows fed, the extreme diet, the relative abundance of the majority of the bins, was significantly altered compared to the other groups. Fibrobacterota and Verrucomicrobiota were less abundant in the Extreme group. Surprisingly, no significant abundance changes were observed among Archaea and Bacteroidota, although abundance changes of individual bins of these phyla were found. For each of the 561 bins, the functions of the metagenome-encoded carbohydrate-active enzymes were predicted by bioinformatics using conserved unique peptide pattern (CUPP) analysis. By linking each of the predicted molecular functions of the enzymes to their substrates, changes were found in the predicted abundance of the different enzyme types. Notably, the decreased CH4 emission of the extreme diet group was concurrent with a profound decrease in the xylan-active enzymes, targeting the xylan backbone β-1,4-linkages, acetyl-, feruloyl-, and methyl-glucuronoyl substitutions in xylan. This work provides a first enzyme-conversion-based characterization of how extreme feeding, i.e., lowered forage, can drive rumen microbiome changes that support decreased CH4 emission via a changed carbohydrate-active enzyme profile. The data, furthermore, provide a metagenome-wide catalog of enzymes, underpinning the microbial conversion of different feed fibers (the enzymes attacking specific carbohydrate linkages) in the rumen of Holstein cows.

Effects of dietary forage to concentrate ratio on nutrient digestibility, ruminal fermentation and rumen bacterial composition in Angus cows

This study evaluated effects of dietary forage to concentrate ratio (F:C) on the body weight, digestibility, ruminal fermentation and rumen bacterial composition in Angus cows. Three diets with different F:C (LCD: 65:35, MCD:50:50, and HCD: 35:65) were fed to ninety Angus cows (3.2 ± 0.18 years old, 387.2 ± 22.6 kg). The average daily gain (ADG) and ammonia nitrogen concentration increased (P = 0.039 and P = 0.026, respectively), whereas the acetate to propionate ratio (P = 0.027) and the neutral detergent fiber (NDF) digestibility decreased with increasing concentrate level. The acetate concentration and ruminal pH (P = 0.033 and P = 0.029, respectively) decreased by feeding HCD diet. Serum amyloid A (SAA), C-reactive protein (CRP), haptoglobin (Hp) and lipopolysaccharide binding protein (LBP) increased under the HCD. The relative abundances of Bacteroidetes, Fibrobacterota, Prevotella and Prevotellaceae UCG-003 decreased, whereas the relative abundances of Ruminococcaceae NK4A214 group, Saccharofermentans and Spirochaetota increased with increasing dietary concentrate level. Our study provides a better understanding of rumen fermentation parameters and microbiota under a wide range of dietary F:C ratios, supporting the potential dietary manipulation of microbes, which could enhance feed digestibility associated with cow rearing.

In vitro methane production from silages based on Cenchrus purpureus mixed with Tithonia diversifolia in different proportions

Climate change (CC) affects food production, mainly those based on livestock systems. Producers must identify adaptation strategies to ensure the production, during periods of drought, and lack of forage. Besides contributing to CC, high emissions of ruminal methane (CH4) are energy loss potentially usable for livestock production. The objective was to estimate in vitro ruminal gas production (RGP) and determine the CH4 emissions from silages. Treatments were made with forage of Cenchrus purpureus mixed with Tithonia diversifolia T1= C.purpureus at 100%; T2= C.purpureus/ T.diversifolia in 33/67 percent ratio; T3= C.purpureus/ T.diversifolia 67/33; and T4= T.diversifolia at 100%. Samples of silages were analyzed, and they were inoculated with strains of Lactobacillus paracasei (T735); then they were fermented in vacuum-sealed bags for 67 days. RGP and CH4 were measured at 2, 4, 8, 12, 18, 24, 30, 36, and 48 hours. Additionally, modeling of CH4 production kinetics was conducted, using different equations. The results indicate that the highest cumulative CH4 production was for T1. This kinetics was represented using the Gompertz model. In conclusion, the inclusion of T.diversifolia to C.purpureus silages contributes to the decrease of methane at the ruminal level, which constitutes an adaptation practice at climate change.

Growth performance, carcass characteristics, and meat quality of Mongolian lambs fed native grass or hay with or without concentrate on the Inner Mongolian Plateau

The aim of this study was to evaluate the effects of native grass on growth performance, carcass characteristics, and meat quality of Mongolian lambs fed Inner Mongolia native grass in three forms: grass, hay, and hay with concentrate (HC). Sixty Mongolian noncastrated male lambs, in good health and with the same age (6 mo) and similar body weights (mean, 28.63 ± 0.19 kg), were randomly divided into three treatments. There were four replicates in each treatment, with five lambs in one pen as a replicate. Compared with the HC group, the intake of the grass group was higher (P < 0.05) and that of the hay group was lower (P < 0.05). The hay group had a gain of −58.67 g d−1, compared with 42.33 g d−1 for the HC group and 80.00 g d−1 for the grass group. The carcass weight, net meat mass, loin muscle area, and fat thickness (a measure of fat tissue thickness) were greater in the grass and HC groups than in the hay group (P < 0.05). Compared with the hay group, the protein and calcium contents, marbling score, and water loss rate were greater in the grass and HC groups (P < 0.05), whereas the fat, phosphorus, cholesterol contents, and b* score were lower for the latter groups (P < 0.05). These results suggest that feeding of native grass hay with concentrate could improve the growth performance and meat quality of Mongolian lambs and achieve results similar to those observed in grass-fed lambs.

Comparative Study of Intake, Apparent Digestibility and Energy and Nitrogen Uses in Sahelian and Majorera Dairy Goats Fed Hay of Vigna unguiculata

This study aimed to compare digestive and metabolic characteristics in Sahelian (S) and Majorera (M) goat breeds. Six lactating females from each breed, with an average weight 27.0 ± 1.93 and 23.7 ± 1.27 kg, respectively, were used. Cowpea hay, variety 58/74, was offered as sole feed ingredient, at a rate of 2 kg of fresh matter per animal per day. The animals were placed in metabolic cages and a digestibility test was conducted according to an adaptation period of 15 days and a collection period of 7 days. The daily chemical components offered and refused and recovered faeces, urine and milk were measured in order to assess energy and nitrogen utilization. The M and S goats had similar levels of dry matter (DM) intake as well as nutrient digestibility. On a metabolic weight basis, dry matter intake, gross energy intake, metabolizable and energy intake, digestible energy and energy lost as methane production were significantly higher (p < 0.01) in M than in S goats. Urinary energy excretion was similar (p = 0.9) between breeds, while faecal energy output was higher in M than in S goats. The milk energy output from the M goats was higher than that the S goats (p < 0.05). However, metabolizable to net energy conversion efficiency (klm) was not affected by breed (p = 0.37), while N intake, milk N yield and faecal N losses, relative to metabolic weight, were significantly higher (p < 0.05) in M than in S goats. Similarly, the percentage of dietary N intake excreted in urine (UNIN) was higher in S than in M breeds. The breed factor had no effect on N retained, N digestibility, urinary N and N use efficiency. In conclusion, the M and S goats were similar in terms of energy and nitrogen use efficiency, despite higher daily milk production and DM consumption in the M goat. This suggests that the M breed is possibly more dependent on a dense nutrition diet than the S breed but requires less maintenance nitrogen.

Animal performance, and enteric methane, manure methane and nitrous oxide emissions from Murrah buffalo calves fed diets with different forage-to-concentrate ratios

The present study aimed to evaluate the effects of dietary forage:concentrate ratios on growth performance and enteric and faecal greenhouse-gas emissions from growing buffalo calves. Fifteen Murrah male calves (bodyweight = 233.35 ± 30.92 kg; 8–12 months age) were randomly assigned to three dietary groups that were fed a mixture of berseem fodder, wheat straw and concentrate at the ratios of 20:60:20 (C20), 20:40:40 (C40) and 20:20:60 (C60) respectively, for 120 days. Enteric methane (CH4) production was estimated by the sulfur hexafluoride tracer technique. Faeces were stored for 12 weeks and CH4 and nitrous oxide (N2O) fluxes from stored faeces were estimated every 14 days. Dry-matter intake, feed conversion efficiency and nitrogen retention were not affected (P &gt; 0.05) but average daily gain and urinary nitrogen loss (g/day) were higher for C60 than the C20 diet (P &lt; 0.05). Daily enteric CH4 emission (g/day) was not affected but CH4 yield (g/kg dry-matter intake) and energy loss through CH4 as a proportion of energy intake were lower for C60 than the C20 diet (P &lt; 0.05). Faeces composition was not affected, and large variations of greenhouse-gas emissions were observed for first 10 days of storage. Methane emissions from stored faces were 1.28 ± 0.40, 1.94 ± 0.34 and 3.90 ± 0.27 mg/kg faeces per day for C20, C40 and C60 diets respectively, being higher for C60 than the C40 and C20 diets (P &lt; 0.05). Methane-flux rate from faeces was greater for C60 than the C20 and C40 diets (0.75 vs 0.26 and 0.37 g/animal respectively; P &lt; 0.05). Diet C60 increased N2O fluxes from stored faeces by 63% and 58% respectively, expressed in mg/kg faeces per day and mg/animal per day, compared with C20 diet (P &lt; 0.05). Overall, dietary concentrate proportion of up to 60% in growing buffalo calf diets improved growth performance without increasing enteric CH4 emission, but CH4 and N2O production from faeces were increased. This work has provided information for gas emissions factors from open storage of faeces. More detailed studies on gaseous emissions from open lots on farms are required.

Contextualized re-calculation of enteric methane emission factors for small ruminants in sub-humid Western Africa is far lower than previous estimates

Given the projected growth of methane emission by ruminants in developing countries, there is a clear need for reliable estimates of their contribution to greenhouse gas emissions. Existing studies have rarely considered sheep and goats. The objective of this study was to predict enteric fermentation methane emission factors (EFs) for Djallonké sheep and West African Dwarf goats, following the 2006 IPCC Tier 2 methodology. Estimated enteric methane emission factors, expressed per head of animal per year, were 2.3 kg CH₄ and 2.0 kg CH₄ for sheep and goats species, respectively. Compared with the generic Tier 1 emission factor of 5 kg CH₄ head proposed by the IPCC for small ruminants in the sub-Saharan Africa region, our suggested values are 56% and 60% lower for sheep and goat, respectively. These lower values took account of the particular flock structure of both sheep and goats. These estimates also accounted for differences in live weight according to age and corresponding estimated feed intake. This work is a step forward in the revision of small ruminant emission factors and can further support assessment of mitigation strategies in Senegalese livestock farming systems.