Livestock production has widely contributed to increase global production of greenhouse gases (GHG), mostly through digestive fermentation in ruminants. Moreover, emissions derived from livestock are estimated over 14% of the total anthropogenic GHG emissions to atmosphere. In addition, methane emitted from ruminal enteric fermentation is responsible for 25% of the total global methane emissions, which turns livestock activity into a main promoter of the climate change effect. However, these emissions may be diminished by modifying livestock diets through alterations in forage-concentrate ratios, the supplementation of feed additives, and the inclusion of alternative feedstuffs not commonly used as forage and protein sources in farm animal feeding. Additionally, the use of nonconventional feedstuffs is highly recommended since their production does not compete with human feeding and may provide metabolites used as methanogenesis suppressors. Likewise, agricultural by-products should be considered as potential feedstuffs for animal production by increasing the livestock efficiency and reducing the energy losses due to methane synthesis.

Objective: To analyze the alternative sources of food for livestock production to mitigate greenhouse gas emissions in Mexico.Design/methodology/approach: A document archive analysis was carried out about the use of certain industrial and agricultural wastes in Mexico in the last decade, and how these can serve as an alternative source of animal feed; these offer certain chemical properties that promote the mitigation of greenhouse gas emissions in livestock systems and also generate an added value in the agricultural and industrial sector.Results: Agricultural and industrial production in Mexico generates an important amount of wastes that are not exploited; in parallel, livestock production in Mexico is growing exponentially, which demands a surface and consumption of natural resources. Therefore, agricultural and industrial residues in Mexico represent a potential alternative source of animal feed, which offers a reduction in the surface destined to the production of food for animals and gives an added value to the industrial and agricultural residues in the country.Study limitations/implications: The alternative sources of food adjust to the agricultural and industrial sectors.Findings/conclusions: The use of agricultural residues, industrial wastes, and other alternate sources of food is suggested as a sustainable alternative in the reduction of GHG in livestock systems and a contribution to the mitigation of climate change in Mexico.