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Papers by Lindeque Du toit

Frontiers in Soil Science

Livestock are an important source of livelihoods in agricultural systems in sub-Saharan Africa (S... more Livestock are an important source of livelihoods in agricultural systems in sub-Saharan Africa (SSA), while also being the largest source of national greenhouse gas (GHG) emissions in most African countries. As a consequence, there is a critical need for data on livestock GHG sources and sinks to develop national inventories, as well as conduct baseline measurements and intervention testing to mitigate GHG emissions and meet ambitious national climate goals. Our objective was to review studies on GHG emissions from livestock systems in SSA, as well as soil carbon storage in livestock-dominated systems (i.e., grasslands and rangelands), to evaluate best current data and suggest future research priorities. To this end, we compiled studies from SSA that determined emission factors (EFs) for enteric methane and manure emissions, along with studies on soil organic carbon (SOC) stocks in SSA. We found that there has been limited research on livestock GHG emissions and SOC relative to nati...

Journal of Animal Science

Probiotics are known to stabilize the microbiome especially in monogastric animals. Limited infor... more Probiotics are known to stabilize the microbiome especially in monogastric animals. Limited information is available on the potential effect on the rumen microbiome. Feedlot cattle are fed high concentrate diets which may result in subclinical and clinical acidosis due to dysbiosis. This can negatively affect the production and lead to morbidities and death. The alpha diversity of a microbiome population and the ratio of Proteobacteria towards Firmicutes and Bacteroidetes have been known to indicate potential dysbiosis. The aim of this study was to investigate the effect of probiotics on the alpha diversity and Proteobacteria ratio of the rumen microbiome of feedlot cattle during the finisher phase. Thirty-six Bonsmara bulls were randomly divided into three groups and fed for 120 days; a basal diet commonly fed in South African feedlots (CTR: control), the basal diet supplemented with monensin (30 mg/animal/day; MON) or a Bacillus-based probiotic (B. licheniformis and B. subtilis; B...

Journal of Animal Science

The threat of the development of an antibiotic resistant bacterium necessitates investigation for... more The threat of the development of an antibiotic resistant bacterium necessitates investigation for alternative feed additives. Probiotics are known to confer a health benefit to the animal and affect the production of the animal through increased nutrient digestibility. The aim of this study was to investigate the bacterial composition of the rumen of South African feedlot cattle when supplemented with a Bacillus probiotic. Twenty-four Bonsmara cattle were randomly divided into two groups: a basal diet (control, CTR) and the basal diet supplemented with Bacillus-based probiotic (B. licheniformis and B. subtilis; Bovacillus, Chr. Hansen A/S; BOV). The animals were fed for 120-days divided by starter, grower, and finisher diets. Four animals from each group were selected for rumen content collection via stomach tube during each phase. DNA extraction was performed and submitted for 16S rRNA sequencing (V3-V4). Approximately 41 300 ASVs were identified from 87 genera using DADA2, phylose...

International Livestock Research Institute, Sep 9, 2020

Animal, 2022

Ruminants are central to the economic and nutritional life of much of sub-Saharan Africa, but cat... more Ruminants are central to the economic and nutritional life of much of sub-Saharan Africa, but cattle are now blamed for having a disproportionately large negative environmental impact through emissions of greenhouse gas (GHG). However, the mechanism underlying excessive emissions occurring only on some farms is imperfectly understood. Reliable estimates of emissions themselves are frequently lacking due to a paucity of reliable data. Employing individual animal records obtained at regular farm visits, this study quantified farm-level emission intensities (EIs) of greenhouse gases of smallholder farms in three counties in Western Kenya. CP was chosen as the functional unit to capture the outputs of both milk and meat. The results showed that milk is responsible for 80-85% of total CP output. Farm EI ranged widely from 20 to >1 000 kg CO 2-eq/kg CP. Median EIs were 60 (Nandi), 71 (Bomet), and 90 (Nyando) kg CO 2-eq/kg. Although median EIs referenced to milk alone (2.3 kg CO 2-eq/kg milk) were almost twice that reported for Europe, up to 50% of farms had EIs comparable to the mean Pan-European EIs. Enteric methane (CH 4) contributed >95% of emissions and manure $4%, with negligible emissions attributed to inputs to the production system. Collecting data from individual animals on smallholder farms enabled the demonstration of extremely heterogeneous EI status among similar geographical spaces and provides clear indicators on how low EI status may be achieved in these environments. Contrary to common belief, our data show that industrial-style intensification is not required to achieve low EI. Enteric CH 4 production overwhelmingly drives farm emissions in these systems and as this is strongly collinear with nutrition and intake, an effort will be required to achieve an ''efficient frontier" between feed intake, productivity, and GHG emissions.

AFMA Matrix, 2017

The recently released Global Feed Survey by Alltech, shows that the global production of compound... more The recently released Global Feed Survey by Alltech, shows that the global production of compound feed has increased to over one billion tons. This increase is associated with a 7% decrease in the number of feed mills globally. According to the Alltech report, the overall combination of increased production from a decreased number of mills, reflects the continued consolidation of agricultural production, despite continued growth in animal protein consumption.

Crop and Pasture Science, 2019

The aim of the study was to evaluate the effect of nitrogen (N) fertilisation on certain quality ... more The aim of the study was to evaluate the effect of nitrogen (N) fertilisation on certain quality parameters and in vitro total gas and methane production of improved grass species commonly used as fodder species in South Africa. Treatments included seven grass species representing two photosynthetic pathways (C3 and C4) with three levels of N fertilisation (0, 50 and 100kg N ha–1). Plants were grown in a greenhouse and N was applied in a single application after a simulated defoliation. Sample material was harvested by hand after an 8-week regrowth period. Grass species and rate of N fertiliser both had effects (P<0.05) on the nutritive value and in vitro organic matter digestibility of the selected species. Crude protein concentration increased (P<0.05) and neutral detergent fibre concentration tended to decrease as the level of N fertilisation increased for both C3 and C4 species. Generally, no effect was found of N fertilisation on in vitro total gas or methane production; ...

All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.

South African Journal …, 2006

... The effect of type and level of carbohydrate supplementation on intake and digestibility of A... more ... The effect of type and level of carbohydrate supplementation on intake and digestibility of Atriplex nummularia cv. De Kock. S.Afr. J. Anim. Sci. 34, 35-37. ... Animal Nutrition. (6th ed.) Adison Wesley. Publ. Longman, Singapore Ltd. Mould, FL, Ørskov, ER & Gauld, SA, 1983. ...

South African Journal of Animal Science, 2014

South African Journal of Animal Science, 2014

There are increasing concerns about the impact of agriculture and livestock production on the env... more 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 (CH 4) and nitrous oxide (N 2 O) 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 CH 4 /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.

Scientia Agricola

ABSTRACT: The high moisture content of wet distillers’ grains with solubles (WDGS) has limited it... more ABSTRACT: The high moisture content of wet distillers’ grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co–ensiling with whole–plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers’ grains (WPMS + DDGS), and whole–plant maize (WPM) co–ensiled with WDGS (WPM – WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rume...

Die belangrikheid van veld en weiding in ’n goeie produktiewe toestand kan nie genoeg beklemtoon ... more Die belangrikheid van veld en weiding in ’n goeie produktiewe toestand kan nie genoeg beklemtoon word nie. Ruvoer vorm die basis van veeproduksie in Suid-Afrika en die benutting van hoe-gehalte ruvoer bly die mees ekonomiese manier vir ’n produsent om sy vee te voer.

AFMA Matrix, 2016

Recently the Department of Environmental Affairs (DEA) published a strategic plan to measure, rep... more Recently the Department of Environmental Affairs (DEA) published a strategic plan to measure, report and verify the greenhouse gas emissions and environmental impact of the agricultural sector. The National Treasury is also in the process of finalising a carbon tax policy and schedule to come into effect on 1 January 2017.

Frontiers in Soil Science

Livestock are an important source of livelihoods in agricultural systems in sub-Saharan Africa (S... more Livestock are an important source of livelihoods in agricultural systems in sub-Saharan Africa (SSA), while also being the largest source of national greenhouse gas (GHG) emissions in most African countries. As a consequence, there is a critical need for data on livestock GHG sources and sinks to develop national inventories, as well as conduct baseline measurements and intervention testing to mitigate GHG emissions and meet ambitious national climate goals. Our objective was to review studies on GHG emissions from livestock systems in SSA, as well as soil carbon storage in livestock-dominated systems (i.e., grasslands and rangelands), to evaluate best current data and suggest future research priorities. To this end, we compiled studies from SSA that determined emission factors (EFs) for enteric methane and manure emissions, along with studies on soil organic carbon (SOC) stocks in SSA. We found that there has been limited research on livestock GHG emissions and SOC relative to nati...

Journal of Animal Science

Probiotics are known to stabilize the microbiome especially in monogastric animals. Limited infor... more Probiotics are known to stabilize the microbiome especially in monogastric animals. Limited information is available on the potential effect on the rumen microbiome. Feedlot cattle are fed high concentrate diets which may result in subclinical and clinical acidosis due to dysbiosis. This can negatively affect the production and lead to morbidities and death. The alpha diversity of a microbiome population and the ratio of Proteobacteria towards Firmicutes and Bacteroidetes have been known to indicate potential dysbiosis. The aim of this study was to investigate the effect of probiotics on the alpha diversity and Proteobacteria ratio of the rumen microbiome of feedlot cattle during the finisher phase. Thirty-six Bonsmara bulls were randomly divided into three groups and fed for 120 days; a basal diet commonly fed in South African feedlots (CTR: control), the basal diet supplemented with monensin (30 mg/animal/day; MON) or a Bacillus-based probiotic (B. licheniformis and B. subtilis; B...

Journal of Animal Science

The threat of the development of an antibiotic resistant bacterium necessitates investigation for... more The threat of the development of an antibiotic resistant bacterium necessitates investigation for alternative feed additives. Probiotics are known to confer a health benefit to the animal and affect the production of the animal through increased nutrient digestibility. The aim of this study was to investigate the bacterial composition of the rumen of South African feedlot cattle when supplemented with a Bacillus probiotic. Twenty-four Bonsmara cattle were randomly divided into two groups: a basal diet (control, CTR) and the basal diet supplemented with Bacillus-based probiotic (B. licheniformis and B. subtilis; Bovacillus, Chr. Hansen A/S; BOV). The animals were fed for 120-days divided by starter, grower, and finisher diets. Four animals from each group were selected for rumen content collection via stomach tube during each phase. DNA extraction was performed and submitted for 16S rRNA sequencing (V3-V4). Approximately 41 300 ASVs were identified from 87 genera using DADA2, phylose...

International Livestock Research Institute, Sep 9, 2020

Animal, 2022

Ruminants are central to the economic and nutritional life of much of sub-Saharan Africa, but cat... more Ruminants are central to the economic and nutritional life of much of sub-Saharan Africa, but cattle are now blamed for having a disproportionately large negative environmental impact through emissions of greenhouse gas (GHG). However, the mechanism underlying excessive emissions occurring only on some farms is imperfectly understood. Reliable estimates of emissions themselves are frequently lacking due to a paucity of reliable data. Employing individual animal records obtained at regular farm visits, this study quantified farm-level emission intensities (EIs) of greenhouse gases of smallholder farms in three counties in Western Kenya. CP was chosen as the functional unit to capture the outputs of both milk and meat. The results showed that milk is responsible for 80-85% of total CP output. Farm EI ranged widely from 20 to >1 000 kg CO 2-eq/kg CP. Median EIs were 60 (Nandi), 71 (Bomet), and 90 (Nyando) kg CO 2-eq/kg. Although median EIs referenced to milk alone (2.3 kg CO 2-eq/kg milk) were almost twice that reported for Europe, up to 50% of farms had EIs comparable to the mean Pan-European EIs. Enteric methane (CH 4) contributed >95% of emissions and manure $4%, with negligible emissions attributed to inputs to the production system. Collecting data from individual animals on smallholder farms enabled the demonstration of extremely heterogeneous EI status among similar geographical spaces and provides clear indicators on how low EI status may be achieved in these environments. Contrary to common belief, our data show that industrial-style intensification is not required to achieve low EI. Enteric CH 4 production overwhelmingly drives farm emissions in these systems and as this is strongly collinear with nutrition and intake, an effort will be required to achieve an ''efficient frontier" between feed intake, productivity, and GHG emissions.

AFMA Matrix, 2017

The recently released Global Feed Survey by Alltech, shows that the global production of compound... more The recently released Global Feed Survey by Alltech, shows that the global production of compound feed has increased to over one billion tons. This increase is associated with a 7% decrease in the number of feed mills globally. According to the Alltech report, the overall combination of increased production from a decreased number of mills, reflects the continued consolidation of agricultural production, despite continued growth in animal protein consumption.

Crop and Pasture Science, 2019

The aim of the study was to evaluate the effect of nitrogen (N) fertilisation on certain quality ... more The aim of the study was to evaluate the effect of nitrogen (N) fertilisation on certain quality parameters and in vitro total gas and methane production of improved grass species commonly used as fodder species in South Africa. Treatments included seven grass species representing two photosynthetic pathways (C3 and C4) with three levels of N fertilisation (0, 50 and 100kg N ha–1). Plants were grown in a greenhouse and N was applied in a single application after a simulated defoliation. Sample material was harvested by hand after an 8-week regrowth period. Grass species and rate of N fertiliser both had effects (P<0.05) on the nutritive value and in vitro organic matter digestibility of the selected species. Crude protein concentration increased (P<0.05) and neutral detergent fibre concentration tended to decrease as the level of N fertilisation increased for both C3 and C4 species. Generally, no effect was found of N fertilisation on in vitro total gas or methane production; ...

All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.

South African Journal …, 2006

... The effect of type and level of carbohydrate supplementation on intake and digestibility of A... more ... The effect of type and level of carbohydrate supplementation on intake and digestibility of Atriplex nummularia cv. De Kock. S.Afr. J. Anim. Sci. 34, 35-37. ... Animal Nutrition. (6th ed.) Adison Wesley. Publ. Longman, Singapore Ltd. Mould, FL, Ørskov, ER & Gauld, SA, 1983. ...

South African Journal of Animal Science, 2014

South African Journal of Animal Science, 2014

There are increasing concerns about the impact of agriculture and livestock production on the env... more 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 (CH 4) and nitrous oxide (N 2 O) 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 CH 4 /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.

Scientia Agricola

ABSTRACT: The high moisture content of wet distillers’ grains with solubles (WDGS) has limited it... more ABSTRACT: The high moisture content of wet distillers’ grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co–ensiling with whole–plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers’ grains (WPMS + DDGS), and whole–plant maize (WPM) co–ensiled with WDGS (WPM – WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rume...

Die belangrikheid van veld en weiding in ’n goeie produktiewe toestand kan nie genoeg beklemtoon ... more Die belangrikheid van veld en weiding in ’n goeie produktiewe toestand kan nie genoeg beklemtoon word nie. Ruvoer vorm die basis van veeproduksie in Suid-Afrika en die benutting van hoe-gehalte ruvoer bly die mees ekonomiese manier vir ’n produsent om sy vee te voer.

AFMA Matrix, 2016

Recently the Department of Environmental Affairs (DEA) published a strategic plan to measure, rep... more Recently the Department of Environmental Affairs (DEA) published a strategic plan to measure, report and verify the greenhouse gas emissions and environmental impact of the agricultural sector. The National Treasury is also in the process of finalising a carbon tax policy and schedule to come into effect on 1 January 2017.