**7. Livestock production and sustainability**

The sustainability of livestock production systems is questioning the potential of livestock production systems for nutrition in recent times. Researchers have called for reducing the environmental cost per unit of livestock considering the current damage caused by the drastic growth in livestock production [59, 60]. Livestock manure produces 65% of human-related nitrous oxide, which has 296 times the global warming potential of carbon dioxide. Livestock account for 37% of all human-induced methane production—and the warming effect of methane is 23 times greater than that of carbon dioxide. Sustainability valuation of livestock food systems is generally based on greenhouse gas (GHG) emissions. But to get a clear picture of the GHG emission scenario we need to thoroughly examine the sectorwise contribution to GHG emission globally. The world emits around 50 billion greenhouse gases each year. According to the data of World Resources Institute, over three quarters of emissions originate from energy usage, nearly one fifth from agriculture and land use (which rises to one quarter when we examine the entire food system—including processing, packaging, transport, and retail), and the rest 8% from industry and waste [see **Figure 2**]. GHG emission is 12–18% from the animal source foods production systems wherein the benefits offered by whole livestock production systems in agriculture, nutrition, health, and other sectors are completely ignored. The overlooked fact is that these benefits counterpoise the

*Leveraging Livestock Production Systems for Human Nutrition in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.101399*

**Figure 2.** *Sector-wise GHG emissions. Source: Climate Watch, World Resources Institute, 2016.*

greenhouse gas emissions, which have declined over the years due to the improved livestock management practices [61].

If we consider the nutrient-rich products derived from livestock production systems which are essential for human health and well-being, the problem of unsustainability like the generation of larger carbon footprints is well balanced [62]. Also, livestock systems contribute to global sustainability by providing various ecosystem services as reported by studies which found that grazing lands has lower greenhouse gas emission or more carbon sequestration than the same land converted for crop production [63] and net accumulation of soil carbon or sink of greenhouse gases was greatest when grassland was converted to silvo-pastures combining trees, forage, and livestock [64]. Furthermore, forage crops make land unfit for cultivation more productive as 57% of forage lands worldwide, are non-cultivable [65]. Also, livestock feeds 86% of products that are inedible by humans like industrial by-products, crop residues, and grasses or fodder, which is then converted into high-value ASF contributing to health and incomes with the bonus of evading environmental pollution from burning or dumping the residues and by-products [66]. Thus, the sustainability of livestock production systems needs to be analysed based on all these facts rather than a one-sided view.
