Factors Affecting Mitigation of Methane Emission from Ruminants I: Feeding Strategies

A Qualitative Assessment of the Trends, Distribution and Sources of Methane in South Africa

Methane (CH4) is the second most important greenhouse gas (GHG) in terms of its concentration and impact on the climate. In the present study, we investigate the trends, sources and distribution of CH4 in South Africa. The study uses satellite datasets from Sentinel-5P and the Atmospheric Infrared Sounder (AIRS). The study also uses credible datasets from the World Bank, Statistics South Africa and the Global Methane Initiative (GMI). The results show an increasing trend of CH4 from 1970–1989. A turning point is observed in 1989, where a decreasing trend is observed from 1989–2001. An increasing trend is then observed from 2001 to 2021. A high concentration of CH4 is observed in the northern and interior parts of South Africa. The results also show that CH4 concentration is influenced by seasonal variations. The September–October–November (SON) season has the highest CH4 concentration distribution in South Africa. The World Bank, Statistics South Africa and the GMI CH4 indictors show that agricultural activities, i.e., involving livestock, are the greatest emitters of CH4 in South Africa, followed by landfill sites. From the livestock data, sheep are the highest emitters of CH4. The increasing CH4 trend is a concern and efforts need to be made to drastically reduce emissions, if South Africa is to meet the 1997 Kyoto Protocol, 2015 Paris Agreement, sustainable development goal 13 (SDG 13) and the COP26 outcome agreements.

Effects of Allium mongolicum Regel supplementation on the digestibility, methane production, and antioxidant capacity of Simmental calves in northwest China

This study evaluated the effects of Allium mongolicum Regel (AM) supplementation on nitrogen (N) balance, ruminal fermentation, and antioxidant properties. Sixteen male calves were assigned randomly to four groups, and the four were added with 0 (CON), 200 mg/kg (body weight; BW) (Low AM; LA), 400 mg/kg (BW) (Middle AM; MA), or 800 mg/kg (BW) (High AM; HA) per day for each individual. AM was added on dry matter (DM) basis. The experiment lasted for 58 days. Supplementation of AM could significantly increase average daily gain, DM digestibility, acid detergent fiber digestibility, and retained N/Intake N. N digestibility and molar proportion of propionate in the MA and HA treatments were higher than that in the CON treatment (p < .05), respectively. AM supplementation significantly increased the molar concentration of total volatile fatty acid in the rumen fluid (p < .05). The ratio of acetate to propionate in the MA and HA groups was lower than that in the CON treatment (p < .05). Furthermore, AM supplementation significantly reduced methane (CH₄ ) (p < .05) emissions. AM supplementation significantly increased the activities of superoxide dismutase. The MA group could significantly increase the activities of glutathione peroxidase and decrease the content of malondialdehyde. Our results indicated that AM supplementation could affect the nutrient digestibility, CH₄ emission, and antioxidant capacity of Simmental calves.

Gas and methane production vis-à-vis loss of energy as methane from in vitro fermentation of dry and green forages in sheep and goat inoculums

Gas production, methane and energy loss from 10 dry and 12 green fodders were evaluated in vitro using sheep and goat inocula. Dry matter intake and digestible DM (DDM) were higher for green (2.45% and 62.28%) than dry fodders (1.72% and 52.88%), respectively. Mean in vitro dry matter digestibility was higher for green than dry fodders in rumen inocula of sheep (63.51 vs 45.34%) and goat (61.36 vs 41.36%), respectively. After 12 h, gas production was higher for green than dry fodders in sheep (69.70 mL/g vs 64.40) and goat inocula (61.73 vs 55.53 mL/g). Gas production was higher for dry and green fodders in sheep inoculums vs goat at 12, 24 and 48 h. At 12 h, methane production was higher for green than dry fodders both in sheep (12.96 vs 9.69 mL/g) and goat (13.34 vs 9.14 mL/g). Total CH4 production was higher for green than dry fodders with both sheep (40.92 vs 33.83 mL/g) and goat inocula (33.34 vs 30.47 mL/g), respectively. Methane production was higher from fermentation of green fodders than dry fodders in rumen inocula from goat (19.27 vs 14.16) and sheep (18.57 vs 14.76 g/kg DM), respectively. Green fodders produced higher CH4 with goat (33.75 g/kg DDM) vs sheep inocula (29.65 g/kg DDM). Methane production (g/kg DDM) and energy loss as methane (CH4 % GE) was similar for dry and green fodders fermented in sheep and goat inocula. Overall, results showed that green forages produced more CH4 compared with dry forages so this piece of information should be put into consideration for sustainable and environmentally friendly production system.

Effects of Feeding Garlic Powder on Growth Performance, Rumen Fermentation, and the Health Status of Lambs Infected by Gastrointestinal Nematodes

Simple Summary

Non-chemical strategies to control gastrointestinal nematodes (GINs) infection are urgently needed to support the sustainable development of the livestock industry. The potential anti-parasitic properties in garlic powder to control sheep GINs was investigated in this study. The key finding of this study was that feeding garlic powder increased growth performance of lambs infected with GINs by decreasing fecal egg counts and improving feed digestion, rumen fermentation, and the health status of lambs.

Abstract

For the study, forty lambs were weighed and assigned into two treatments to determine the effects of feeding garlic powder on growth performance, rumen fermentation, and the health status of lambs infected with gastrointestinal nematodes (GINs). The lambs were fed with a basal diet without or with 50 g/kg garlic powder for 84 d. Data were analyzed by a general linear or mixed model of SAS software and differences were considered statistically significant if p ≤ 0.05. Results showed that garlic powder supplementation increased the lambs’ average daily gain (p = 0.025), digestibility of dry matter (p = 0.019), and crude protein (p = 0.007). No significant changes were observed on the dry matter intake, feed conversion ratio, as well as the apparent digestibility of lipid and fiber. An interactive effect between treatment and feeding day was observed on ruminal pH (p < 0.001) and ammonia nitrogen concentration (p < 0.001). Ruminal pH (p < 0.001) and ammonia nitrogen concentration (p < 0.001) decreased with garlic powder supplementation, while ammonia nitrogen concentration increased (p = 0.001) with the extension of the feeding period. Garlic powder supplementation increased the total volatile fatty acid concentration (p < 0.001) in the rumen fluid, the molar proportion of acetic acid (p = 0.002), propionic acid (p < 0.001), and isovaleric acid (p = 0.049), but it decreased the ratio of acetic acid to propionic acid (p = 0.015). The lambs’ fecal egg count decreased (p < 0.001), but the packed cell volume and body condition scores of lambs increased (p < 0.001) with garlic powder supplementation. In conclusion, feeding garlic powder increased growth performance, feed digestion, rumen fermentation, and the health status of lambs infected with GINs.

Effects of natural blends of garlic and eucalypt essential oils on biogas production of four fibrous feeds at short-term of incubation in the ruminal anaerobic biosystem

BACKGROUND

The present study explored the effect of garlic and/or eucalypt oils on biogas production during in vitro ruminal fermentation of four agro industry byproducts. For this, 0-180 mg oil L^-1 incubation medium was added and gas volumes were recorded from 2 to 48 h of incubation. Dry matter substrate degradability and neutral as well as acid detergent fibre were determined after 72 h.

RESULTS

Gas production and nutrient degradability was oil type dependent. The oils enhanced (P < 0.05) biogas and asymptotic biogas production for corn stalks and oat straw, although no effect was observed on asymptotic biogas production for sorghum straw and sugarcane bagasse. Addition of both oils decreased (P < 0.05) fermentation pH for corn stalks, sorghum straw and oat straw and also increased (P < 0.05) dry matter degradability for all four byproducts. Neutral detergent fibre degradability for all byproducts was higher (P < 0.05) with garlic oil. Eucalypt oil, however, decreased (P < 0.05) neutral detergent fibre degradability for sugarcane bagasse and corn stalks, although only weak effects were observed for sorghum and oat straws.

CONCLUSION

With respect to ruminal biogas production, the addition of garlic oil showed better environmental effects than the addition of eucalypt oil and increasing oil concentrations resulted in enhanced fermentation characteristics. © 2018 Society of Chemical Industry.

Nutritional characteristics and in vitro digestibility by near-infrared spectroscopy of local and hybrid napiergrass varieties grown in rain-fed and irrigated conditions

Napiergrass can produce large amounts of biomass and its nutritive value has a significant effect on its effectiveness for animal production. However, temperature and drought stress limit its productivity. Drought-tolerant pearl millet × napiergrass hybrid (PMN) varieties were developed and produce high biomass yields. The nutritional content and digestibility of PMN is not well known, which limits its use in animal feeding. It was hypothesised that PMN hybrids are more drought tolerant and have higher nutritive value than napiergrass varieties. Four napiergrass varieties (Bana grass, Mott, MB4, and N51) and four PMN (PMN2, PMN3, 5344, 4604) were tested with or without irrigation treatment in a strip-plot design, with the objective of evaluating the nutritional value and in vitro digestibility of PMN hybrids and napiergrass. The forages were harvested on Day 110 of planting. Samples were hand chopped, oven-dried, ground to pass through a 1-mm screen and analysed for their nutrient content and in vitro digestibility using near-infrared spectroscopy. Dry matter (DM) content of PMN2 (24.3%) and PMN3 (22.9%) was significantly higher (P < 0.05) than 5344, Bana grass and N51 napiergrass varieties. No differences (P > 0.05) in acid detergent fibre, neutral detergent fibre, crude protein and metabolisable energy were found among napiergrass varieties. With no effect (P > 0.05) of irrigation, lignin content was highest (P < 0.08) in 4604 (8.2%) and lowest in 5344 (5.2%). Starch was highest (P < 0.05) in irrigated MB4 than both irrigated and non-irrigated 4604. Non-fibre carbohydrate content was highest (P < 0.05) in PMN2 (12.8%) than MB4 (8.7%). The in vitro true digestibility was significantly higher (P < 0.05) in 5344 and Bana grass (70.0% and 68.0% of DM, respectively), than PMN3 (54.5%). Rate of digestion was significantly higher (P < 0.05) in 5344 (4.9%/h) than PMN2 (2.7%/h), others were in between. Neutral detergent fibre digestibility (NDFD) of 5344 and Bana grass (56.7% and 53.2% of neutral detergent fibre, respectively) was significantly higher (P < 0.05) than PMN2 (38.0%). Although no effect of irrigation was observed, there was an interaction (P < 0.05) between variety and irrigation on neutral detergent fibre digestibility of napiergrass varieties. In conclusion, among four PMN varieties tested, PMN3 and 5344 has higher nutritional value and in vitro digestibility than PMN2 and 4604 even when grown in non-irrigated condition. Thus, PMN3 and 5344 is the preferred napiergrass variety for animal feeding, even in rain-fed farming conditions.

Effect of supplementing orchardgrass herbage with a total mixed ration or flaxseed on fermentation profile and bacterial protein synthesis in continuous culture

A 4-unit dual-flow continuous culture fermentor system was used to evaluate the effects of supplementing fresh herbage with a total mixed ration (TMR) or flaxseed on nutrient digestibility, fermentation profile, and bacterial N synthesis. Diets were randomly assigned to fermentors in a 4 × 4 Latin square design. Each fermentor was fed a total of 70 g of dry matter/d of 1 of 4 diets: (1) 100% freeze-dried orchardgrass herbage (Dactylis glomerata L.; HERB), (2) 100% freeze-dried TMR (100TMR), (3) 50% orchardgrass herbage supplemented with 50% TMR (50TMR), or (4) 90% orchardgrass herbage supplemented with 10% ground flaxseed (Linum usitatissimum L.; FLAX). Preplanned, single degree of freedom orthogonal contrasts were constructed to assess the effects of feeding system (HERB vs. 100TMR), herbage supplementation (HERB vs. 50TMR + FLAX), and herbage supplemental source (50TMR vs. FLAX). Compared with the HERB diet, the 100TMR diet significantly reduced apparent digestibility of neutral detergent fiber. Herbage supplementation with 50TMR or FLAX significantly reduced or tended to reduce apparent digestibilities of dry matter, organic matter, and neutral detergent fiber, suggesting that replacing high-quality, highly digestible fresh herbage with forage TMR likely caused depressions in nutrient digestibilities. Concentration of total volatile fatty acids, molar proportions of acetate, propionate, and isovalerate, as well as the acetate:propionate ratios were all significantly higher in fermentors fed 100TMR compared with HERB, likely in response to enhanced supply of fermentable energy. In general, feeding system, herbage supplementation, and type of supplementation did not affect N metabolism in the present study. The few significant changes in N metabolism (e.g., flows of total N and non-NH3-N) were primarily linked to increased fermentor N supply with feeding herbage-based diets (HERB and FLAX). Although TMR-based diets decreased nutrient digestibility slightly, TMR offered advantages in bacterial fermentation in relation to volatile fatty acid production, which could potentially translate into better animal performance. Flaxseed shows promise as an alternative supplement for herbage-based diets; however, further in vivo evaluation is needed to determine the optimal level to optimize animal production while reducing feed costs.