Scielo RSS <![CDATA[South African Journal of Animal Science]]> http://www.scielo.org.za/rss.php?pid=0375-158920130003&lang=es vol. 43 num. 3 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Special issue: A balanced perspective on animal production, from environment to human health</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892013000300001&lng=es&nrm=iso&tlng=es <![CDATA[<b>Should we reject animal source foods to save the planet? A review of the sustainability of global livestock production</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892013000300002&lng=es&nrm=iso&tlng=es Within the next 40 years, the global livestock industry will have to considerably increase production in order to supply the population with animal-source foods, yet the industry must concurrently improve the three metrics of sustainability - economic viability, environmental stewardship and social responsibility. Environmental stewardship is currently the area for which animal agriculture is under the most scrutiny, as many consumers perceive that animal-source foods have an unacceptable environmental cost. These concerns are intensified by activist group campaigns propounding that reducing meat consumption will have significant environmental mitigation effects. Animal-source foods have been shown to be essential dietary components for improving health of inhabitants in developing regions, for whom such foods are often economically unavailable. Moreover, reducing meat consumption in developed countries has a negligible effect upon national greenhouse gas (GHG) emissions and leads to further questions with regards to the implications for use of animal and plant by-products, and the difficulty of producing human food crops on grazed pasturelands. Improving livestock productivity has positive sustainability implications as it reduces resource use and GHG emissions whilst improving economic viability, yet it is often difficult to attain consumer acceptance of modern best practices and technologies. Productivity metrics that enhance sustainability include milk and meat yield, growth rates, feed efficiency, calving rate, parasite control and use of growth-enhancing technologies. <![CDATA[<b>A South African perspective on livestock production in relation to greenhouse gases and water usage</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892013000300003&lng=es&nrm=iso&tlng=es The general perception that livestock is a major contributor to global warming resulted mainly from the FAO publication, Livestock's Long Shadow, in 2006, which indicated that livestock is responsible for 18% of the world's greenhouse gas (GHG) emissions. This figure has since been proved to be an overestimation, since it includes deforestation and other indirect contributions. The most recent figure is in the order of 5% - 10%. Although only ruminants can convert the world's high-fibre vegetation into high-quality protein sources for human consumption, ruminant production systems are targeted as they are perceived to produce large quantities of GHG. Livestock is also accused of using large quantities of water, an allegation that is based on questionable assumptions and the perception that all sources of food production require a similar and equal quantity and quality of water. In the case of ruminants, extensive systems are usually found to have a lower per-area carbon footprint than grain-fed systems, but a higher footprint if expressed in terms of kg product. Feedlots maximize efficiency of meat production, resulting in a lower carbon footprint, whereas organic production systems consume more energy and have a bigger carbon footprint than conventional production systems. Cows on pastures produce more methane than cows on high concentrate diets. In South Africa, as in most of the countries in the sub-tropics, livestock production is the only option on about 70% of the agricultural land, since the marginal soils and rainfall do not allow for crop production and the utilization of green water. An effective way to reduce the carbon and water footprint of livestock is to decrease livestock numbers and increase production per animal, thereby improving their efficiency. <![CDATA[<b>Climate change and livestock production</b>: <b>A review with emphasis on Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892013000300004&lng=es&nrm=iso&tlng=es Climate change and its effects on existence on earth are becoming more and more relevant as physical evidence of change in our climate is beginning to mount. Livestock production and our dependence on it for survival is a reality. It is also a reality that this global source of food and income will be prone to the effects of climate change. Historic climate changes have already played a role in the demise or development of agricultural production systems. This review article will give insight into the most important livestock production species and the possible effects of climate change on their production parameters. The species to be discussed are dairy cattle, beef cattle, small ruminants and monogastric production animals. The results and predictions of global studies and simulations are summarized with special emphasis, where possible, on the southern African scenario. This review deals with these changes and possible adaptations and mitigations. All predictions indicate that livestock production at local, national and regional level may undergo changes in the foreseeable future. <![CDATA[<b>Livestock breeding for sustainability to mitigate global warming, with the emphasis on developing countries</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892013000300005&lng=es&nrm=iso&tlng=es Global warming is predicted to have a profound effect on livestock production in developing countries. An improved understanding of the adaptation of livestock to such changing production environments is thus important, but the measurement of adaptation is complex and difficult. Proxy-indicators for adaptation, such as reproductive and production traits, however, can be used. Livestock industries have a responsibility to reduce the release of greenhouse gases (i.e. the carbon footprint) and water use (i.e. the water footprint). An effective way of decreasing the carbon and water footprints from livestock is to reduce livestock numbers and increase the production per animal. Increased production generates less greenhouse gas emissions per unit of livestock product. Proper definition of breeding objectives and trait definition is essential in implementing efficient breeding systems to cope with climate change. Sophisticated statistical models continue to support animal breeding and improvement, especially with respect to production traits. Traits linked to fertility and survival are still problematic and appropriate genetic technology to properly characterize these traits needs to be developed. Gene or marker-assisted selection may play an important role in selection for disease and parasite resistance or tolerance, since it is generally difficult to measure these traits directly. Strategies that utilize breeding values derived from genomic analyses may speed up the process of breeding animals with higher and more efficient production and that are adapted to the changing environments as a result of global warming. However, both genetic and epigenetic controls influence genetic expression and should be taken into account when formulating breeding programmes. Subsistence farmers keep livestock for multiple purposes and the formulation of breeding objectives/strategies will have to consider these dynamics.