Scielo RSS <![CDATA[South African Journal of Animal Science]]> http://www.scielo.org.za/rss.php?pid=0375-158920180006&lang=pt vol. 48 num. SPE lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>A glance at achievements of SASAS and animal scientists in southern Africa over more than 50 years</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600001&lng=pt&nrm=iso&tlng=pt With the congress theme of 'Golden Innovations for Sustainable Animal Agriculture', it would be opportune to look not only at innovations with present and future potential, but at those 'golden innovations' that have been achieved and established over more than five decades. Many of these innovations still form the basis of many aspects of present-day sustainable animal agriculture in southern Africa. This brief review covers three areas, namely the history of the South African Society for Animal Science (SASAS), achievements of animal scientists, mainly in the earlier years of the Society, and the coming of age of professionalism in the animal science profession. The South African Society of Animal Production (SASAP) was founded on 28 April 1961 in Pretoria. The name was later changed to the South African Society for Animal Science. The theme of the first congress of SASAP was 'Efficiency in Production', a theme that is still relevant. In 1971 the South African Journal of Animal Science (SAJAS) was initiated, and by 2017 the 47th volume has been published. A large amount of knowledge that is applicable to local conditions has accumulated and should be drawn upon to avoid 'reinventing the wheel'. In the 1950s to 1970s, Professor Jan Bonsma developed the concept of functional efficiency of cattle and principles that focused on adaptability and sustainability. Extensive research was conducted on the feeding of urea and phosphorus to grazing livestock, leading to the practice of urea-containing rumen-stimulating winter supplementation of ruminants. South Africa was considered a world leader in the field of supplementary feeding practices. South Africa has a proud history in the discipline of animal genetics and the practical application of breeding principles to enhance livestock productivity, and is in the forefront with studies on the genomics of livestock in southern Africa. SASAS was instrumental in establishing the professional status of animal scientists in South Africa. The vision is that an animal scientist should be identified as the expert in his/her field and the best qualified person to advise on matters such as animal breeding, nutrition and general management of livestock. SASAS council also acts as a mouthpiece for and custodian of animal scientists. The society protects the interests of animal scientists, is pro-active in promoting animal science, and acts as a watchdog over the professional activities of members. <![CDATA[<b>Genomics for the advancement of livestock production: A South African perspective</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600002&lng=pt&nrm=iso&tlng=pt Most of the growth of human populations worldwide will be in developing countries, including South Africa. Natural resources are under immense pressure and animal scientists are faced with the challenges for increased efficiency and long-term sustainability of livestock production. Since the completion of the Human Genome Project, animal genomes have been mapped with genomics, enabling new opportunities for application in farm animal species. The use of microsatellite markers has made significant contributions to the insight in genetic characterisation of indigenous and local developed breeds in most farm species in South Africa and Africa. The single nucleotide polymorphic (SNP) marker discovery and development of commercial SNP arrays made genomic selection possible and genomic enhanced breeding values (GEBVs) are used widely in the First World. In South Africa, genomic programmes for beef and dairy cattle were established in 2015 and 2016, with the focus on building training populations for genomic selection. The SA Bonsmara breed was the first to receive GEBV. The availability of hard-to-measure phenotypes is limited, and these are the traits that hold the most potential for genomic selection and answering to the challenges of methane (CH4) emissions and higher efficiency. Genome editing, which involves zinc-finger nucleases (ZFNs), transcription-activators such as endonucleases (TALEN) and RNA-programmable genome editor (CRISPR/CAS9), includes the most recent technology for application in precision genetics. Welfare and ethical concerns will be an important consideration in the acceptability of genome editing to consumers. Applications that benefit the animals are more acceptable to the public. The use of genome editing to produce polled cattle is one of the first applications with a direct welfare impact as it nullifies the need for painful dehorning. In this paper, genomic technology is reviewed with the focus on the most recent research trends and commercial application of genomics towards the genetic improvement of livestock with specific reference to South Africa. <![CDATA[<b>Meat in a sustainable food system</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600003&lng=pt&nrm=iso&tlng=pt Meat has been an important component of the human diet for centuries as a rich source of essential nutrients required for development, growth and maintenance. In addition to its nutritional value, meat production and processing provide employment and income generation in both commercial and informal farming sectors. However, in recent times, the sustainability of meat production, as well as the quality and safety of meat products has come under intense scrutiny as a result of the negative implications of livestock farming and meat consumption on the environment and human health, respectively. These concerns have become increasingly important to consumers and significantly influence consumption trends and the viability of the meat industry. Meat quality, safety and nutritional composition are influenced by the wide range of conditions to which meat-producing animals are exposed from 'farm to fork'. Hence, a complete understanding of meat and factors affecting it at every stage of the production chain is beneficial for the control and enhancement of meat quality. Additionally, adopting a systems approach is key to minimizing the negative implications of the meat industry on the environment and health. Current farming conditions are characterized by increasingly variable weather patterns and a diminishing natural resource base. As such, determining environmentally friendly, climate resilient and sustainable production systems is crucial. Pre- to post-slaughter processes tailored to maximize carcass yields, minimize losses and prevent health risks are essential. Furthermore, there is a growing need among consumers for transparency and detailed information on meat production and composition. Research that links the dynamics involved in all stages of meat production is necessary to sustain the positive role of meat in the human diet and to maximize the contribution of meat towards the alleviation of food insecurity, while easing the impact on the environment. <![CDATA[<b>Driving forces for changes in geographic range of cattle ticks (Acari: Ixodidae) in Africa: A review</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600004&lng=pt&nrm=iso&tlng=pt Ticks are the most important external parasites of cattle and are known to transmit more pathogens than any other group of arthropods worldwide. About 80% of the world cattle population is at risk of ticks and tick-borne diseases, causing a global annual loss of $US22-30 billion. In Africa, the impact of ticks is ranked high, and they transmit diseases such as cowdriosis, anaplasmosis, bovine babesiosis and theileriosis. A range expansion of ixodid ticks has been observed in Africa, in particular for the genera Amblyomma and Rhipicephalus, which contribute greatly to cattle loss owing to morbidity and mortality. Distributional changes in ticks can lead to the emergence or re-emergence of infectious and parasitic diseases. Climate change is frequently invoked as the primary cause of tick distribution, but it is not the only factor. Human lifestyle changes, including transportation of livestock within countries, have promoted the introduction of new tick species and the diseases they transmit. One such example is the spread of the Asian cattle tick Rhipicephalus (Boophilus) microplus to West Africa. Rhipicephalus (Boophilus) microplus was recorded for the first time in Namibia and was probably introduced into Namibia from South Africa. Likewise, Amblyomma variegatum, the vector of heartwater disease, has the largest distribution in Africa. Its spread is outside its native range and it is considered the second most invasive tick species after R. (B.) microplus on the continent. Rhipicephalus (Boophilus) microplus is a one-host tick that is reported to be resistant to conventional acaricides and this contributes largely to its spread into non-endemic areas. <![CDATA[<b>Environmentally smart animal agriculture and integrated advisory services ameliorate the negative effects of climate change on production</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600005&lng=pt&nrm=iso&tlng=pt The objective is to discern how Charles Darwin's Origin of species (1859) and the theory of natural selection and evolutionary biology - 'a grain in the balance will determine which individual shall live and which shall die'- are core to achieving environmentally and climate-smart, economically viable, sustainable animal agriculture in a changing climate. Darwin's 'survival of the fittest' theory implies inherent comparative advantage of survivors over the succumbed in any given environment. An animal's phenotype (P) results from interaction of its genotype (G) and the environment (E), expressed as P = G x E. Human migration has transferred livestock breeds from places of origin to distant continents and agro-ecological zones, far from where they have inherent comparative production advantage. For example, crossbreeds of Bos taurus and Bos indicus have higher average performance than median of either parent population. However, the heterotic effect of hybrids is associated with loss of environmental adaptation compared with parent populations. Indigenous breeds, their phenotypes and ecotypes thrive best in distinct environments, ceteris paribus. An environment is the sum total of conditions that influence animal productivity in the habitat. These include nutrition, genetics, disease, exposure to parasites, management practices, climate, rainfall, humidity, heat and cold stressors, and advisory services. Hybrids lose some adaptive capacity compared with parents, and require habitat modifications if they are to express their fullest genetic potential. In the light of this and of global warming challenges to livestock production, it is scientifically and technically prudent to exploit the inherent comparative production advantages of indigenous genotypes, phenotype and ecotypes, when mitigating climate change, more so in low-input animal agriculture systems of sub-Saharan Africa and at similar locations. Climate change poses multidisciplinary challenges that require integrated collaborative cross-discipline research, extension and training to provide holistic solutions. <![CDATA[<b>Fertility in dairy cows and ways to improve it</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600006&lng=pt&nrm=iso&tlng=pt The fertility of dairy cows affects the genetic improvement and financial sustainability of dairy herds. Fertility is a complex trait that is affected by several factors. Genetically, fertility is difficult to improve because of low heritability. Cows that do not become pregnant are usually culled from the herd. This paper reviews results from studies conducted in South Africa that are aimed at improving the reproductive performance of dairy cows. Records from 9 046 cows in 14 Holstein herds showed that, while lactation number, calving year and calving season affected fertility traits significantly, herd management had the largest effect. Mean ± sd for calving to first service (CFS) and from calving to conception (DO) intervals were 77 ± 30 and 134 ± 74 days, respectively. The number of services per conception (SPC) was 2.55 ± 1.79. The proportion of first services within 80 days post partum and cows confirmed pregnant within 100 and 200 days post partum were 0.64 ± 0.48, 0.36 ± 0.48, and 0.71 ± 0.45, respectively. Heritability (h²) estimates were 0.06, 0.08 and 0.07 for CFS, DO, and SPC, respectively. Albeit low h²estimates were consistent with literature results, the genetic correlation between CFS and DO was positive (0.56), and negative (-0.29) between CFS and pregnancy success. Crossbreeding, using a dual-purpose breed, improved fertility, similar to studies conducted overseas. Increasing the energy content of the total diet of Holstein cows on kikuyu-ryegrass pasture by feeding 7 kg versus 12 kg concentrates/cow/day, improved fertility as a higher proportion of cows were pregnant by 150 days in milk, being 0.52 versus 0.84 and 0.56 versus 0.76 for primi-and multiparous cows, respectively. Estimating breeding values for fertility traits for breeding sires would assist in improving fertility in dairy cows. <![CDATA[<b>Global poultry production: Current impact and future outlook on the South African poultry industry</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892018000600007&lng=pt&nrm=iso&tlng=pt Poultry meat and eggs are the largest source of animal protein in the human diet worldwide. These are the benefits of decades of poultry research investments that were aimed at developing fast-growing strains, a better understanding of nutrient metabolism and utilization, and the effects of those nutrients on gene expression. The South African poultry industry has advanced alongside global trends in most developed countries. The industry is dominated by a few fully integrated large commercial producers, and a high volume of small-scale producers, either as contract growers or individual producers supplying solely the informal market. Currently, the poultry industry is battling to remain competitive, owing to tons of imported dark chicken meat being dumped in this market by other countries at prices below the cost of production locally. This has had negative consequences on producers, big and small, and on the employment rate. Disease outbreaks, welfare regulations, food safety, house environment and a number of issues relating to nutrition and feeding are among current and future challenges to the poultry industry, particularly the small-scale segment. With urbanization escalating, land availability and accessibility for intensive poultry rearing, and crop production for feed will be a challenge. Simultaneously, although poultry has the lowest carbon and water footprint, global warming is likely to affect feed quality and quantity, increasing feed and energy costs, thereby influencing food security. In future, maize and soybean meal on a worldwide basis will remain the major ingredients in poultry diets, although research on feedstuffs for partial replacement of these two will still be relevant, more so for home mixers. Focus on poultry science education and training, research and extension partnerships between poultry scientists and veterinarians also needs serious attention. Lack of collaboration between the private and public sectors, and lack of innovative ways to articulate concerns from producers and consumers to policy makers remain barriers to technological adoption. This review adopts poultry in sole reference to chickens.