Steps to Sustainable Ruminant Livestock Production.

Global agriculture is at a critical juncture where competing requirements for maximal production and minimal pollution impose various patterns of economic-environmental trade-offs. Livestock production is central to this debate, as it is estimated to generate 7.1 Gt CO2-e of greenhouse gases (GHG) each year, or 14.5 percent of human-induced GHG emissions across the world. The sector is said to occupy 30% of the Earth’s surface, of which one-fifth is subject to land degradation due to inappropriate management and overproduction. These statistics, together with the notion that cereals and pulses currently being fed to livestock animals could potentially be consumed by humans to alleviate hunger, have frequently led to a criticism that livestock farming is an unethical industry.

Livestock, on the other hand, may be able to make important contributions to food security. Ruminants can utilise land unsuitable for arable crop production and convert fibre and low quality nitrogen sources to nutritionally-valuable human-edible protein. These forms of protein are generally known to be of higher quality in terms of both composition (amino acid profile) and bioavailability than those originating from plants, and are also associated with vital micro-nutrients which plants are often poor sources of e.g. Fe, Zn, I, Se and Vitamin B-12, providing a case for the role of animals as part of a balanced diet. Furthermore, grazing animals have been shown to be net providers of a range of ecosystem services and, depending on the natural conditions, capable of not only maintaining but also regenerating soil fertility by facilitating nutrient cycling. Given these conflicting views, there is a clear and urgent need to evaluate the pros and cons of different livestock production systems and appropriately define their role in society (Eisler et al., 2014).