Die internasionale aandeel van elektriese voertuie wat van die kragnetwerk af herlaai word se verkope was 8,6% in 2021, in vergelyking met Suid-Afrika se 0,1%. Die verhoging van die verkoop van hierdie voertuie in Suid-Afrika is direk gekoppel aan die voortbestaan van Suid-Afrika se voertuigvervaardigingsbedryf. Om hierdie uitdaging die hoof te bied, moet besighede en regerings die faktore wat die aanvaarding van elektriese voertuie beïnvloed, beter verstaan. Hierdie studie het beduidende faktore geïdentifiseer wat die aanvaarding van elektriese voertuie beïnvloed en daardeur beïnvloed word. Deur middel van 'n literatuurstudie, is talle faktore geïdentifiseer en daarna gekarteer in 'n kousale lusdiagram met 'n aangepaste sisteemdinamika-benadering. Die impak van belasting op die koste van elektriese voertuie en die lae beskikbaarheid van elektrisiteit beïnvloed beide verbruikersvertroue in die besit van 'n elektriese voertuig en plaaslike vervaardigingskapasiteit negatief. Hierdie model dien as 'n nuttige hulpmiddel om te verstaan hoe verskeie faktore in Suid-Afrika die aanvaarding van elektriese voertuie beïnvloed en daardeur beïnvloed word.

The international share of plug-in electric vehicle sales was 8.6% in 2021, compared with South Africa's 0.1%. Increasing the sale of these vehicles in South Africa is directly tied to the continued existence of South Africa's vehicle manufacturing industry. To address this challenge, businesses and governments need to understand better the factors influencing electric vehicle adoption. This study identified significant factors that influence and are influenced by electric vehicle adoption. By reviewing the current literature, numerous factors were identified and mapped in a causal loop diagram with an adapted system dynamics approach. The impact of taxation on the cost of electric vehicles and the low availability of electricity negatively affects both consumer confidence in owning an electric vehicle and local manufacturing capacity. This model serves as a useful tool to piece together how various factors in South Africa affect and are affected by electric vehicle adoption.

Objectives of this research were to examine differential gene expression profiles of Nguni and Bonsmara cattle fed diets differing in their energy density. The ultimate goal was to improve understanding of the mechanisms that underlie differences between these breeds and the potential interactions of the differences between breeds with the nutritive environment. The experiment was designed as a 2 χ 2 factorial arrangement of breed and diet (12.5 MJ/kg DM vs. 10.9 MJ/kg DM). The initial feeding trial had 10 bull calves per treatment. However, financial constraints limited RNA sequencing to six animals per treatment and the RNA generated from one animal was of insufficient quality to be useful. Transcripts with false discovery rate P-values <0.05 and fold-changes >2.0 were considered significant. Bonsmara had a faster growth rate, heavier live and carcass weights, and better feed conversion compared to Nguni. However, lower levels of fat were observed in Nguni. Twenty different genes were differentially expressed, with three exhibiting interaction effects and all 20 having differences in transcript abundance between the breeds. A dietary effect was only observed for the one gene and that gene was also subject to an interaction effect with breed. Observed differences in gene expression between Bonsmara and Nguni by several genes affecting the structure or function of the mitochondria imply differences in energy metabolism between the breeds. Interaction effects on the abundance of some gene transcripts indicate the need to consider the diet when evaluating breed differences and conversely, consider breed when evaluating diets.

The sustainability of beef cattle producers in South Africa is greatly dependent on the availability of natural resources. The aim of the study was first to evaluate the effect of two different strategies in the utilisation of rangeland over four years (2011/12 - 2014/15) on the basal cover-secondly, the study compared animal production results from the two extensively managed rotational grazing strategies. Grazing strategies include a traditional rotational system (TRG), where approximately 60% of fodder was utilised, compared with light selective grazing (LSG), where about 30% of fodder was used. Basal cover for TRG ranged from 19% (2011/12) to 15% (2014/15) and for LSG from 18% (2011/12) to 16% (2014/15). The calving percentage varied between 62% and 73%. The calving percentage and cow and calf weight did not differ between the two grazing strategies, although differences between years were observed. Both grazing systems can be implemented successfully in the Sourish Mixed Bushveld without negatively affecting the rangeland. However, basal cover may be more vulnerable during drought conditions under a TRG system. The study further indicates that mainly small-scale farmers, where utilisation levels of rangelands are usually high, are more vulnerable to drought conditions.

BACKGROUND: Inadequate weight gain could indicate clinical deterioration in infants and children living with HIV (CLHIV). The World Health Organization's (WHO) weight-for-age z-score (WAZ) growth standards and reference charts are currently used in South Africa to assess weight gain in CLHIV on antiretroviral treatment (ART). OBJECTIVES: To assess weight gain patterns of infants and children initiated on ART and to compare weight gain patterns between the WHO WAZ growth standards and population-specific curves constructed from data of CLHIV on ART METHOD: A quantitative, retrospective and descriptive-comparative design was used. The weight gain patterns of 98 infants and children from birth to 10 years old during the 24-month period following ART initiation were recorded and assessed using two different growth charts. RESULTS: The children's rate of weight and length gain improved significantly over 24 months since ART initiation, but complete catch-up growth was never achieved. Most (69%) of the children had increased weight gain according to the WAZ growth standard and reference charts versus only 16% according to the HIV-specific weight gain curves. CONCLUSION: Antiretroviral treatment improved weight and height gain in CLHIV, but the interpretations of weight gain differed significantly between the WHO chart and HIV-specific weight gain curves. Population- and treatment-specific references could improve weight monitoring in CLHIV and assist in the timeous identification of malnutrition.

The hands-on use of complex, industrial Enterprise Resource Planning (ERP) systems in educational contexts can be costly and complex. Tools that simulate the hands-on use of an ERP system have been proposed as alternatives. Research into the perceived usefulness (PU) and perceived ease of use (PEOU) of these simulation tools in an m-learning environment is limited. As part of this study, an m-learning simulation application (SYSPRO Latte) was designed based on experiential learning theory and on a previously proposed theoretical framework for m-learning. The application simulates the hands-on experience of an ERP system. The purpose of this paper is to analyse the results of a study of 49 students who used SYSPRO Latte and completed a questionnaire on its PEOU and PU. The results revealed that students perceived SYSPRO Latte to be easy to use and useful, and verified other studies identifying a correlation between PEOU and PU. The study also confirmed the benefits of simulation-based learning and m-learning particularly for content presentation. The importance of considering design principles for m-learning applications was highlighted. This study is part of a larger, comprehensive research project that aims at improving learning of ERP systems in higher education.

Heat stress, as a consequence of global warming, can have a profound effect on dairy cattle in South Africa. In this paper, current milk production data of Holstein dairy herds on pasture in South Africa, together with climate variables related to heat stress, were used to model and identify geographical areas for optimal milk production under current and future climatic conditions. To model the influence of heat stress on milk production of Holstein dairy herds on pasture in South Africa, the maximum entropy (Maxent) modelling technique was used in a novel approach to model and map optimal milk-producing areas. Geographical locations of farms with top milk-producing Holstein herds on pasture were used as presence-only data points. Only three of a possible eight climate variables that made significant contributions to the model were included, namely evaporation rate, relative humidity and mean annual temperature. The modelling technique showed good capability to capture the geographical influence of heat stress on milk production of Holstein dairy cattle and to reconstruct this relationship in sites where no data were available. The method performed well with low test omission rates, an area under curve (AUC) value of 0.929, and mean training data predictive rate of 0.66 (SD = 0.13). The modelled map indicated optimal milk production areas in the eastern parts of South Africa, which correlates well with the geographical influence of heat stress as represented by the temperature humidity index for the country. Future climate change projections (2046-2065) were used to predict optimal milk-producing areas for the future, indicating progressive shrinking of currently suitable areas and a geographical shift towards the southern parts of the east coast of South Africa. Possible long-term viable alternatives are suggested, including changes in nutrition and replacing existing breeds with more heat tolerant genotypes.

The objective of this study was to assess the effect of place of birth on the reproductive performance of two Nguni ecotypes (Nguni and Landim) raised in a sub-tropical environment to enhance strategies for livestock development and restocking programmes within the southern African region. Reproduction data collected between 1994 and 2009 from 301 cows of the Landim (n = 122) and Nguni (n = 179) ecotypes were analysed. Results indicated that ecotype and place of birth had significant effects on age at first calving (AFC) and calving interval (CI). The means for AFC were 1085 and 1003 days, those for CI were 422 and 436 days, while the calving rate (CR) was 90.0% and 85.7% for the Nguni and Landim, respectively. This study demonstrates for the first time a possible genotype by environment interaction between Nguni ecotypes. This might aid future cattle development and restocking programmes in southern Africa, taking into consideration the adaptation of indigenous genotypes and climate change.

The FAO publication, Livestock's Long Shadow, indicated that livestock is responsible for 18% of the world's greenhouse gas production thereby creating the perception that livestock is a major cause of global warming. Methane (CEL) makes up 16% of total world gas emissions and is the second most important greenhouse gas (GHG) after carbon dioxide (CO2). Ruminants are important to mankind since most of the world's vegetation biomass is rich in fibre and only ruminants can convert this vegetation into high quality protein sources for human consumption. In spite of this important role of livestock, it is singled out as producing large quantities of GHG that contribute to climate change, since enteric fermentation is responsible for 28% of global CH4 emissions. However, the net effect from livestock is only a 4.5% contribution to GHG. The livestock industry should be aware of the effect of livestock on climate change and therefore it is important that mechanisms are put in place to mitigate this effect. The improvement of production efficiency through increased production per constant unit, crossbreeding and genetic improvement may be a cost effective and permanent way of reducing the carbon footprint of beef cattle.