Direct methane and nitrous oxide emissions of South African dairy and beef cattle

The objective of this study was to estimate direct methane and nitrous oxide emissions of South African dairy and beef cattle in total and per province using the Tier 2 methodology of the Intergovernmental Panel on Climate Change (IPCC), but adapted for tropical production systems. Dairy and beef cattle in 2010 contributed an estimated 964 Giga gram (Gg) or 72.6% of the total livestock methane emissions in South Africa. Beef cattle in extensive systems were the largest contributor (83.3%), followed by dairy cattle (13.5%), and feedlot cattle (3.2%). The enteric methane emission factors for dairy cattle of 76.4 kg CH4/head/year and 71.8 kg CH4/head/year for concentrate fed and pasture-based production systems, respectively, were higher than those reported by other developing countries, as well as the IPCC default value of 46 kg CH4/head/year for developing countries. The beef cattle methane emission factors of 78.9 kg CH4/head/year and 62.4 kg CH4/head/year for commercial and emerging/communal cattle, respectively, were similar to those reported by other developing countries, but higher than the IPCC default value of 31 kg/head/year. Primarily because of cattle numbers, Eastern Cape recorded the highest dairy and beef cattle methane emissions, whereas Gauteng showed the highest feedlot methane emissions.The National Research Foundation of South Africa and the RMRD SA.http://www.sasas.co.zaam201

Direct greenhouse gas emissions of the South African small stock sectors

There are increasing concerns about the impact of agriculture and livestock production on the environment. As a result, it is important to have accurate estimations of greenhouse gas (GHG) emissions if reduction measures are to be established. In this study the direct GHG emissions from South African sheep and goats during 2010 were calculated. Calculations were done per province and in total. The Intergovernmental Panel on Climate Change (IPCC) methodology, adapted for tropical production systems, was used to calculate methane (CH4) and nitrous oxide (N2O) emissions on a Tier 2 level. Small stock is a key methane emission source in the South African livestock sector, and is responsible for an estimated 15.6% of the total livestock emissions. Small stock contributed an estimated 207.7 Giga gram (Gg) to the total livestock methane emissions in South Africa in 2010, with sheep producing 167 Gg and goats producing 40.7 Gg. Calculated enteric methane emission factors for both commercial and communal sheep of 8.5 kg/head/year and 6.1 kg/head/year, respectively, were higher than the IPCC default value of 5 kg CH4/head/year for developing countries. A similar tendency was found with goat emission factors. The highest sheep and goat methane emissions were reported for the Eastern Cape province, primarily because of animal numbers.The National Research Foundation of South Africa and the RMRD SA.http://www.sasas.co.zaam201

Direct methane and nitrous oxide emissions of monogastric livestock in South Africa

There are increasing concerns about the impact of agriculture and livestock production on the environment. In this the greenhouse gas emissions (GHG) from South African pigs, ostriches, horses, donkeys, mules and poultry were calculated, using 2010 production data on a provincial basis. The Intergovernmental Panel on Climate Change (IPCC) methodology adapted to tropical production systems was used to calculate methane (CH4) and nitrous oxide (N2O) emissions. The non-ruminant sector is a minor GHG contributor compared with ruminant CH4 and N2O emissions. The pig industry and ostrich industry both contribute approximately 8 Gg (Giga gram) CH4 /year. The poultry industry is the largest direct N2O producer of the non-ruminant livestock industries, contributing 2.3 Gg/year or 92.8% of the total non-ruminant N2O emissions.The National Research Foundation of South Africa and the RMRD SA.http://www.sasas.co.za/am201

Direct greenhouse gas emissions of the game industry in South Africa

Previous greenhouse gas (GHG) inventories did not include game as an emissions source. Recently game farming has become a recognized commercial enterprise in the agricultural sector in South Africa, contributing approximately R10 billion to the sectorial gross domestic product. The objective of this study was to estimate methane (CH4) and nitrous oxide (N2O) emissions from privately owned game animals based on international recognized methodologies. The emissions were calculated on the basis of a large stock unit (LSU) selecting different quality diets. Daily enteric methane emissions were estimated as 0.28, 0.22, and 0.18 kg CH4/LSU/day consuming diets of 55%, 65% and 75% digestibility, respectively. The game industry contributed an estimated 131.9 Giga grams (Gg) of methane annually to agricultural emissions with the provinces of Limpopo, Eastern Cape and Northern Cape being the three largest contributors with 43.4, 37.3 and 21 Gg methane, respectively. The total privately owned game population was estimated at 299 1370 animals, utilizing 20.5 million hectares.The National Research Foundation of South Africa and the RMRD SA.http://www.sasas.co.za/am201

Effects of feeding system and pre-partum supplementation on the beta-carotene status of South African Holstein cows

The objectives were to investigate the ß-carotene status of dairy cows under various production systems, and to determine the effect of pre-partum ß-carotene supplementation on their post-partum ß-carotene status. Ten farms were selected from each of the three production systems, namely pasture-based, hay-based total mixed ration (TMR) and silage-based TMR. Twenty cows per farm were sampled in each system, and blood plasma ß-carotene concentration was determined with a portable spectrophotometer (n = 200 cows per system). Mean blood ß-carotene concentrations of pasture-fed cows were 5.54 mg/L, and were higher (P <0.05) than concentrations of cows on hay-based (2.98 mg/L) and maize silage-based TMR systems (1.71 mg/L); in ß-carotene status, therefore, these systems were optimal, marginal, and deficient, respectively. In the second experiment, 10 cows received a hay-based control TMR, and 10 were supplemented with 1.2 g/day of ß-carotene pre-partum from day -56 to calving and monitored until day 56 postpartum. The supplemented cows were in optimal ß-carotene status until calving, with a minor carry-over effect until 10 days post partum, and then declined gradually in status until they needed supplementation. The ß-carotene status between the groups differed from three weeks pre-partum to two weeks post partum, with the control group being marginal to deficient from three weeks pre-partum onwards. Forage type and its ß-carotene content play a major role in the ß-carotene status of cows and more research is needed on the potential storage and mobilization of ß-carotene in cows.DSM Nutritional Products.https://www.sasas.co.za/resources/sa-journal-animal-scienceAnimal and Wildlife Science

Elucidating the Antimycobacterial Mechanism of Action of Decoquinate Derivative RMB041 Using Metabolomics

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), still remains one of the leading causes of death from a single infectious agent worldwide. The high prevalence of this disease is mostly ascribed to the rapid development of drug resistance to the current anti-TB drugs, exacerbated by lack of patient adherence due to drug toxicity. The aforementioned highlights the urgent need for new anti-TB compounds with different antimycobacterial mechanisms of action to those currently being used. An N-alkyl quinolone; decoquinate derivative RMB041, has recently shown promising antimicrobial activity against Mtb, while also exhibiting low cytotoxicity and excellent pharmacokinetic characteristics. Its exact mechanism of action, however, is still unknown. Considering this, we used GCxGC-TOFMS and well described metabolomic approaches to analyze and compare the metabolic alterations of Mtb treated with decoquinate derivative RMB041 by comparison to non-treated Mtb controls. The most significantly altered pathways in Mtb treated with this drug include fatty acid metabolism, amino acid metabolism, glycerol metabolism, and the urea cycle. These changes support previous findings suggesting this drug acts primarily on the cell wall and secondarily on the DNA metabolism of Mtb. Additionally, we identified metabolic changes suggesting inhibition of protein synthesis and a state of dormancy

Effects of silage sealing films on fermentation dynamics of ensiled maize and nutrient utilization by Damara rams

An experiment was conducted to evaluate the effects of two silage sealing films on whole crop maize (WCM) fermentation, aerobic stability and nutrient digestion by rams. Prior to ensiling (day 0), triplicate samples of the WCM were collected to determine dry matter, pH, water-soluble carbohydrates (WSC), lactic acid (LA) bacterial counts and nutrient concentration. A single bunker silo was divided into eight sections that were ensiled using either a standard polyethylene film (PE) or an orange oxygen barrier (OB) Silostop film for 180 days. After 180 days of ensiling, six silage samples were collected from each replicate. Three samples were used for nutrient analysis and the other three to determine aerobic stability. Sixteen four-year-old Damara rams with an average live weight of ± 54 kg were housed individually in wooden pens (2.2 m2) to determine digestibility of nutrient in the silage. The digestibility study was conducted as a switchover design with four feeding phases. The silage was supplemented daily with 1% urea and fed to the rams ad libitum. Nutritional value of the silage was not (P >0.05) affected by the ensiling films. The OB-ensiled maize had higher (P 0.05) by treatments. The OB film improved the fermentation and aerobic stability of WCM silage but did not influence its nutrient utilization by rams.The National Research Foundationhttp://www.sasas.co.zaam2021Animal and Wildlife Science

Rumen microbial diversity of Bonsmara cattle using amplicon sequencing during a 120-day growth trial

Improved understanding of the microbial populations during intensive feeding of feedlot cattle holds potential for optimizing production efficiency. Ionophores are used to increase the production and efficiency of ruminants and are commonly used in South African feedlots. Bonsmara bull calves (n=24) were subject to a four-phase feedlot diet in a growth trial commencing with backgrounding, followed by starter, grower and finisher diets. Animals were randomly divided into two groups: control and a group provided the in-feed ionophore monensin. Four animals from each group were randomly selected for rumen content collection using an oesophageal tube during the phases in the trial. Samples were analysed using 16S rRNA and internal transcribed spacers amplicon sequencing. Totals of 42 008 and 35 442 amplicon sequence variants were identified from 16S rRNA and internal transcribed spacers amplicon sequencing. The rumen microbiome composition and alpha diversity differed significantly between the phases, whereas no significant difference was observed between the control and monensin groups. Backgrounding had the highest bacterial richness, whereas the grower phase had the highest fungal richness. Bacteroidetes, Firmicutes and Proteobacteria were the most abundant phyla, with Bacteroidetes being most abundant in the backgrounding and starter phases, whereas Proteobacteria was the most abundant in the grower and finisher phases. Ascomycota, Basidiomycota and Neocallistigomycota were the most abundant fungal phyla. Improved knowledge of the shift in microbiome population during the growth period could assist in adapting feeding strategies to improve the efficiency of beef production.Red Meat Research and Development South Africa, Sernick Group (PTY) LTD and the Meat Industry Trust.http://www.sasas.co.zaam2023Animal and Wildlife Science

Elucidating the antimycobacterial mechanism of action of ciprofloxacin using metabolomics

In the interest of developing more effective and safer anti-tuberculosis drugs, we used a GCxGC-TOF-MS metabolomics research approach to investigate and compare the metabolic profiles of Mtb in the presence and absence of ciprofloxacin. The metabolites that best describe the differences between the compared groups were identified as markers characterizing the changes induced by ciprofloxacin. Malic acid was ranked as the most significantly altered metabolite marker induced by ciprofloxacin, indicative of an inhibition of the tricarboxylic acid (TCA) and glyoxylate cycle of Mtb. The altered fatty acid, myo-inositol, and triacylglycerol metabolism seen in this group supports previous observations of ciprofloxacin action on the Mtb cell wall. Furthermore, the altered pentose phosphate intermediates, glycerol metabolism markers, glucose accumulation, as well as the reduction in the glucogenic amino acids specifically, indicate a flux toward DNA (as well as cell wall) repair, also supporting previous findings of DNA damage caused by ciprofloxacin. This study further provides insights useful for designing network whole-system strategies for the identification of possible modes of action of various drugs and possibly adaptations by Mtb resulting in resistance.https://www.mdpi.com/journal/microorganismsam2022Plant Production and Soil Scienc