L.J. Erasmus

The impact of animal source food products on human nutrition and health

Throughout the ages the quest for food and drink has influenced humanity’s economic, social and political development, and played a role in the organization of society and history. Nutrition (or what we choose to consume) influences the health of human beings and therefore their quality of life. Animal source foods are often the dietary component that evokes the widest array of complex scientific, economic, environmental and political issues. It is viewed as the most expensive component of any diet, yet can make significant contributions to human health through providing high quantities of essential nutrients. In addition to quantity, the high quality of the nutrients in animal source foods is important as high-quality nutrients are more readily absorbed into the human body than lower-quality nutrients from other food and non-food sources. As South Africans increasingly suffer the consequences of inappropriate diets (overand undernutrition), the role of animal source foods as part of a healthy diet requires continuous investment in research and extrapolation of information towards appropriate guidelines and recommendations. Although it is often suggested that the intake of animal source foods should be limited because of possible linkages between animal product consumption and health, scientific evidence increasingly indicates the beneficial role that animal source foods can play in preventing and combating obesity and certain non-communicable diseases related to over-nutrition. This article aims to describe the nutritional role of animal source foods as part of a healthy South African diet and presents a review of recent findings related to their nutrient contribution, as well as evidence relating to common health concerns. ________________________________________________________________________________

Technical note: A simple back-mounted harness for grazing dairy cows to facilitate the sulfur hexafluoride tracer gas technique

We describe here a cattle harness to attach a gas collection vessel to facilitate the sulfur hexafluoride (SF6) tracer gas technique. The harness consists of 2 major components: (1) a lightweight, robust body fabricated from an equine surcingle or lunge roller with padded thoracic trapezius pressure points, a bespoke shaping shaft for spine support, and adjustable buckles on both sides; and (2) an elastic flank-strap to prevent the harness from dislodging. The spine support consists of stainless steel laminated with carbon fiber. This support minimizes the contact area with the animals skin, relieves the spine area of pressure, and creates free flow of ambient air below the platform, reducing sweat accumulation and hence preventing skin lesions. The harness weighs approximately 1.2 kg, allows for attachment of 2 gas collection vessels (animal and background sample), and is cost effective.

Effect of Megasphaera elsdenii NCIMB 41125 dosing on rumen development, volatile fatty acid production and blood β-hydroxybutyrate in neonatal dairy calves.

Thirty calves were randomly assigned to two treatments and fed until weaning [42 days (d) of age]. Treatments were a control group (n = 15), which did not receive Megasphaera elsdenii (Me0) and a M. elsdenii group, which received a 50-ml oral dose of M. elsdenii NCIMB 41125 (10(8) CFU/ml) at day 14 day of age (Me14). Calves were given colostrum for the first 3 day followed by limited whole milk feeding. A commercial calf starter was offered ad libitum starting at day 4 until the end of the study. Fresh water was available throughout the study. Feed intake and growth were measured. Blood samples were collected via jugular venipuncture to determine β-hydroxybutyrate (BHBA) concentrations. Fourteen male calves (seven per group) were euthanised on day 42 and digestive tracts harvested. Reticulo-rumen weight was determined and rumen tissue samples collected from the cranial and caudal sacs of the ventral and dorsal portions of the rumen for measurements of papillae length, papillae width and rumen wall thickness. Dosing with M. elsdenii NCIMB 41125 improved starter dry matter intake (DMI), weaning body weight (BW) and tended to improve average daily gain. Calves in Me14 group had greater plasma BHBA concentration than Me0-calves during the last 3 weeks of the trial and had at day 42 greater reticulo-rumen weight, papillae width and papillae density compared to Me0. No differences in rumen wall thickness or papillae length were observed between the two groups. Total volatile fatty acids, acetate and propionate production did not differ between treatments, but butyrate production was greater in Me14 than Me0. Dosing M. elsdenii NCIMB 41125 showed benefit for calves with improved feed intake and rumen development suggesting increased epithelium metabolism and improved absorption of digestive end products.

Audit tools and techniques : crucial dimensions of internal audit engagements in South Africa

Abstract The paper presents secondary empirical data from the Common Body of Knowledge study, on the use of audit tools and techniques by internal auditors in South Africa and compared its findings on South African internal audit functions with those of developed regions. It investigates the current use of the audit tools and techniques by the internal auditors in South Africa. This paper also reviewed relevant literature to support arguments for the use of audit tools and techniques by the internal auditors. The study found that internal audit functions in South Africa use audit tools and techniques similar to that of developed regions. The paper also found that internal auditors mostly use audit tools and techniques, such as risk based planning electronic, communication, analytical reviews and working papers. The paper concludes that, while other audit tools and techniques are important to have, the most preferred enhances the quality of the audit process.

Nutrient composition and in vitro methane production of sub-tropical grass species in transitional rangeland of South Africa

The development of greenhouse gas mitigation strategies has become an important issue globally. Enteric methane (CH4) emissions from livestock do not only contribute substantially to the environmental footprint of livestock production but it also represents a loss of energy that could be channelled towards animal growth and production. In this study 14 sub-tropical grass species typical of transitional rangeland regions of South Africa were characterised in terms of ecological status, chemical composition, in vitro total gas and CH4 production. The aim of the study was 2-fold: to identify grass species that could be selected for low enteric CH4 production; evaluate the influence of rangeland ecological status on the methanogenic potential of a rangeland. Grass samples were collected by hand, air-dried, milled and analysed for nutrient composition, in vitro organic matter digestibility (IVOMD) and in vitro gas and CH4 production. Cenchrus ciliaris and Urelytrum agropyriodes produced the highest 48-h in vitro CH4 of 17.49 and 14.05 mL/g DM digested respectively. The lowest 48-h in vitro CH4 was produced by Andropogan gayanus and Bothriochloa bladhii with 5.98 and 6.08 mL/g DM digested respectively. The evaluated grass species were overall of poor quality with low CP concentrations ranging from 2.4% for Trachypogon spicatus to 6.7% for Digitaria eriantha and IVOMD ranging from 22.5% for Andropogon gayanus to 42.2% for Urelytrum agropyriodes. Decreaser grass species presented with higher in vitro CH4 production compared with Increaser I and Increaser II grass species in the present study. The results of the study emphasise the importance of including the nutritional potential of grass species for improved livestock production when evaluating grass species for possible greenhouse gas mitigation strategies.

The Effective Use of Blended Learning Tools that Promote Success among Low Performing South African Undergraduate Students

A major problem in higher education in South Africa is the low success rate and high dropout rate of undergraduate students. The high dropout rate could be the result of socio-economic factors, academic shortcomings or merely the fact that the current way of teaching does not meet the needs of the 21st century student. In this literature review paper, the aim was twofold. First, existing literature was reviewed to identify research conducted on blended learning tools that can promote student success and the relationship between the research conducted and practical applications of these blended learning tools were indicated. Second, five key success factors were selected and the role of blended learning, as well as its tools, were discussed in relation to the key success factors. The result and contribution is a list of proposed blended learning tools, with suggestions on its use, to address the factors that influence students’ success by enhancing the learning process. It is recommended that further research be conducted to determine by means of a pilot approach, the extent to which the use of these blended learning tools is successful in enhancing student success.

Effect of concentrate level on enteric methane emissions, production performance and rumen fermentation of Jersey cows grazing kikuyu-dominant pasture during summer

The effect of concentrate feeding level on enteric CH4 emissions from cows grazing medium quality summer pasture is yet to be investigated. Sixty multiparous Jersey cows (9 rumen-cannulated) were used in a randomized complete block design study (with the cannulated cows in a 3 × 3 Latin square design) to investigate the effect of concentrate feeding level (0, 4, and 8 kg/cow per day; as-fed basis) on enteric CH4 emissions, production performance, and rumen fermentation of dairy cows grazing summer pasture (17 cows plus 3 cannulated cows per treatment). Enteric CH4 emissions were measured from 11 cows per treatment group during one 7-d measurement period using the sulfur hexafluoride tracer gas technique. Pasture dry matter intake (DMI) was determined parallel with the CH4 measurement period using TiO2 as an external marker, and milk yield, milk composition, cow condition, and pasture pre- and postgrazing measurements were also recorded. Daily total DMI (11.2 to 15.6 kg/cow), milk yield (9.1 to 18.2 kg/cow), energy-corrected milk (ECM; 11.2 to 21.6 kg/cow), and milk lactose content (44.1 to 46.7 g/kg) increased linearly, whereas pasture DMI (11.2 to 8.4 kg/cow) decreased linearly with increasing concentrate feeding level. Daily CH4 production (323 to 378 g/d) increased linearly due to the increase in total DMI, whereas CH4 yield (29.1 to 25.1 g/kg of DMI) and CH4 intensity (35.5 to 21.1 g/kg of milk yield; and 28.8 to 17.6 g/kg of ECM) decreased linearly with increasing concentrate feeding level. Diurnal ruminal pH (6.45 to 6.32) and in sacco DM and neutral detergent fiber disappearance decreased linearly. Acetic and propionic acid were unaffected by treatment, whereas butyric acid (5.21 to 6.14 mM) increased linearly and quadratically with increasing concentrate feeding level. It was concluded that a high concentrate feeding level not only increases animal efficiency but is moreover a viable CH4 mitigation option for dairy cows grazing kikuyu-dominant pasture in late summer when pasture is inherently fibrous.

Substitution of rumen degradable nitrogen with urea in sheep fed low quality Eragrostis curvula hay

The aim of the present study was to determine whether sunflower meal (SFM), a highly rumen degradable protein (RDP) source, can be substituted with non-protein nitrogen (NPN, urea) without impacting negatively on intake, digestibility, rumen fermentation and microbial nitrogen (N) synthesis (MNS) in wethers consuming low quality Eragrostis curvula hay. Five wethers were fed ad libitum, low quality hay and supplemented twice-daily in equal proportions, via the rumen cannulae, one of five iso-nitrogenous and iso-energetic supplements in a 5 × 5 Latin square design experiment. The supplements differed in the ratios of rumen degradable N (RDN) supplied by either SFM and/or urea and is presented as percentage of RDN supplied by urea: T0 (100 % SFM, 0 % urea); T15 (85 % SFM, 15 % urea); T30 (70 % SFM, 30 % urea); T45 (55 % SFM, 45 % urea) and T60 (40 % SFM, 60 % urea). Forage intake and total tract dry matter (DM) digestibility did not differ; however, higher forage neutral detergent fiber (NDF) digestibilities were observed in the sheep supplemented with the higher urea-treatments (T45 and T60) compared to T15. Neither rumen pH nor total rumen volatile fatty acid (VFA) concentraions differed. The mean rumen ammonia nitrogen (RAN) concentration of the sheep supplemented with T60 was higher than T30 (9.35 mg dL−1 vs. 7.41 mg dL−1); however, no differences were observed in MNS or efficiency of MNS among treatments. Results suggest that up to 60 % of RDN supplied by SFM can be substituted with urea, without affecting intake, digestibility or MNS in wethers fed a low quality tropical hay.