The impact of climate change on extensive and intensive livestock production systems

The majority of animal scientists and livestock producers are fully aware and accept that the livestock production sector contributes to factors causing climate change and that in turn livestock production will also be affected by climate change. These effects will be both direct and indirect (Houghton et al., 2001). The impact of climate change on animal production has been categorized as the following: 1) availability of feed in the form of grain, 2) pasture and forage crop production and quality, 3) health, growth, and reproduction, and 4) diseases and the spread thereof (Rotter and Van de Geijn, 1999). In this article, the potential impact of projected climate change on the different livestock production systems (extensive and intensive) will be discussed in general with emphasis on the adaptation aspect. It is, however, important to put the livestock production sector into perspective before speculating on potential future changes. What do we mean when we talk about livestock production and what is the definition of livestock? It is defined as domesticated animals raised in an agricultural production system with the aim of producing food, fiber, and labor. Sometimes, reference is only made to ruminants, such as cattle, sheep, and goats but this definition should include all livestock which fits the original description, including poultry, pigs, and so on. Over time the livestock sector has increased in size and relative production output, especially in intensive animal farming practices (Muir, 2011). The increase in intensive beef cattle production in beef feedlots is due to the increasing global demand for protein (Millen et al., 2011; Costa Junior et al., 2012). In Brazil, Costa Junior et al. (2012) reports that the number of beef cattle fed in feedlots has more than doubled since 2012. Verge et al. (2008) ascribe this to the fact that this increase was driven by both population increases and the increased demand for higher rates of protein inclusion in human diets. A positive correlation exists between the expansion of beef cattle enterprises and those for the other species, where the same trend is observed. This increase has also been observed by the IPCC where an estimated 1.4-fold increase in numbers for cattle, buffalo, sheep, and goats, and a 1.6and 3.7-fold increase for pigs and poultry, respectively, has taken place since 1970s (Smith et al., 2014). Livestock systems, especially in developing countries, are extremely dynamic and various drivers of change can be identified. This includes increasing populations and incomes which are combining to drive considerable growth in demand for livestock products. This is projected to continue well into the future (Delgado et al., 1999), although at diminishing rates (Steinfeld et al., 2006). A second feature of the growing demand for livestock products is the shift in the location of production. An example of this is the rapid urbanization of (particularly monogastric) livestock production (the landless monogastric production system—LLM systems), followed in time by ruralization again. This second ruralization move is primarily in response to environmental drivers, meaning that after the initial urbanization, the pressures on resources and environmental pollution forces these production systems to less densely populated rural areas again. In addition to the factors associated with the “livestock revolution” (Delgado et al., 1999) and “livestock in geographic transition” (Steinfeld et al., 2006), other drivers may have far-reaching impacts on the livestock sector in the coming decades: the green agriculture movement (organic food, fair trade, etc.) and the increasing importance of fodder crops being grown for biofuel, for example. There may be considerable impacts of climate change on agricultural systems in the future, but it is clear that climate change is only one of several key drivers of change. Other factors such as population Implications