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

AbstractThe objectives were to investigate the β-carotene status of dairy cows under various production systems, and to determine the effect of pre-partum β-carotene supplementation on their post-partum β-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 β-carotene concentration was determined with a portable spectrophotometer (n = 200 cows per system). Mean blood β-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 β-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 β-carotene pre-partum from day -56 to calving and monitored until day 56 postpartum. The supplemented cows were in optimal β-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 β-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 β-carotene content play a major role in the β-carotene status of cows and more research is needed on the potential storage and mobilization of β-carotene in cows

Ensiling quality of maize as influenced by the addition of wet distillers grains with soluble

Wet distillers grains with soluble (WDGS) were blended with whole maize plants on an as-fed basis at 0%, 20%, 30%, and 40% and ensiled in 3 L bottles to evaluate the silage fermentation characteristics and ensiling quality in a complete randomized design. Each treatment was ensiled in 15 mini-silos and three bottles were opened on days 7, 21, 42 and 120. Each treatment was sampled for chemical composition and silage fermentation parameters. There was a steady decrease in dry matter (DM) concentration of silage with increasing WDGS inclusion level over time. Initial pH (at day 0) decreased with increasing level of WDGS inclusion, with 40% WDGS inclusion recording the lowest pH (3.6) at day 120. Lactic acid concentration was slightly lower for WDGS-blended silages compared with the control. In contrast, the acetic acid concentration for WDGS-blended silage increased across all treatments, suggesting a possible diminished effect of clostridium bacteria in the silage owing to a reduced pH. The acid detergent fibre (ADF), neutral detergent fibre (NDF) and IVDOM (in vitro digestible organic matter) did not differ at the time of ensiling among treatments. During post ensiling, ADF increased slightly over time for WDGS-blended treatments (at 120 days). The results from this study indicated that WDGS could be ensiled effectively with maize plants without compromising silage quality.WAVNhttp://www.sasas.co.zaam2016Animal and Wildlife Science

The effect of type and level of carbohydrate supplementation on intake and digestibility of Atriplex Nummularia cv. De Kock fed to sheep

The aim of this study was to investigate the effect of different carbohydrate sources, with rapid and medium fermentabilities, on the digestibility and rumen fermentability of Atriplex nummularia cv. De Kock fed to sheep. Maize was used as the medium fermentable carbohydrate source and barley as the rapid fermentable carbohydrate source. The trial ran in four sequential experimental periods using two groups of animals. The two groups stayed constant during the entire trial, one group receiving the maize treatment and the other the barley treatment. During each experimental period the groups of animals received different levels of the two carbohydrate sources. Each experimental period consisted of a digestibility trial and a rumen fermentation trial. Four different levels of supplementation were used, namely 0, 15%, 30% and 45%. Measurements included dry matter intake, water intake, percentage dry matter digestibility, percentage neutral detergent fibre digestibility, rumen pool sizes, rumen pH, rumen ammonia nitrogen and rumen volatile fatty acid production. Supplementation of A. nummularia cv. De Kock with an energy source tended to increase feed and water intake. The tendency of energy sources to increase dry matter and neutral detergent fibre digestibilities diminished when the level of supplementation was raised from 15% to 30% and from 30% to 45%. The results suggest that maize and barley supplementation at a level of 15% resulted in the highest incremental increase in dry matter and neutral detergent fibre digestibilities of A. nummularia cv. De Kock. The results also indicated that energy supplementation tended to increase dry matter intake and rumen fill. Rumen pools of dry matter, neutral detergent fibre and total nitrogen all increased with an increase in the level of supplementation. The tendency of energy supplementation to increase the different rumen pools diminished as the level of supplementation increased from 30% to 45% for both the energy sources. The results also indicate that the rumen environment was more favourable for fibre degradation when maize was used as an energy source. In the final phase it is reported that ruminal ammonia nitrogen increased as the rate of supplementation was increased from the 0% to the 15% level. The drop in rumen ammonia nitrogen as the rate of supplementation was increased to 30% indicates an improvement in microbial protein synthesis. Ruminal pH decreased as the rate of supplementation increased with barley supplemented animals having lower rumen pH values. The decrease in rumen pH supports the increase in volatile fatty acid production as the level of energy supplementation was increased. It is concluded that an energy supplement of maize or barley will increase the intake and digestibility of A. nummularia cv. De Kock and that a level of 30% should be optimal for microbial protein synthesis without significantly affecting fibre degradation.Dissertation (MSc Agric (Animal and Wildlife Sciences))--University of Pretoria, 2007.Animal and Wildlife Sciencesunrestricte

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

Data describing cattle performance and feed characteristics to calculate enteric methane emissions in smallholder livestock systems in Bomet County, Kenya

This dataset describes the performance of cattle in smallholder livestock systems of Bomet county in western Kenya. Information on live weight, milk production and quality, herd dynamics, and other production parameters were collected from field visits. Animals were weighed on scales; milk yield was recorded using a Mazzican® milk collection and transport vessel provided to each farm and milk was analyzed for butterfat content (%). Pasture biomass yield was determined, and feed samples collected for each agro-ecological zone and nutrient composition was determined for nitrogen (N) using the Kjeldahl method and gross energy (GE) using a bomb calorimeter. Distance covered while grazing was determined using GPS collars fitted to several animals for three consecutive days per area. Enteric methane (CH(4)) emissions factors (EF) were estimated for five animal classes to develop site-specific EFs as per the Intergovernmental panel on climate change (IPCC) protocol. This dataset has the potential to be used, amongst other purposes, for animal-scale life cycle assessment (LCA) to evaluate the efficacy of various greenhouse gas (GHG) mitigation options

Research progress on greenhouse gas emissions from livestock in sub-Saharan Africa falls short of national inventory ambitions

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 national ambitions for climate change mitigation in SSA. Enteric methane emission factors (EFs) in low productivity cattle systems may be lower than IPCC Tier 1 default EFs, whereas small ruminants (i.e. sheep and goats) had higher EFs compared to IPCC Tier 1 EFs. Manure EFs were equal to or lower than IPCC Tier 1 EFs for deposited manure (while grazing), manure applied as fertilizer, and manure management. SOC stocks for grasslands and rangelands in SSA show broad agreement with IPCC estimates, but there was a strong geographic bias and many studies did not report soil type, bulk density, or SOC stocks at >30 cm depth. In general, the largest data gaps included information for manure (quantity, quality, management), small ruminants, agropastoral/pastoralist systems, and in general from West Africa. Future research should focus on filling major data gaps on locally appropriate mitigation interventions and improving livestock activity data for developing Tier 2 GHG inventories in SSA. At the science-policy interface, all parties would benefit from enhanced coordination within the research community and between researchers and African governments to improve Tier 2 inventories and harmonize measurement for mitigation in livestock systems in SSA