How much the reproductive losses of sows can be impacting the carbon footprint in swine production?

•Pork farming has become a significant source of food worldwide.•Sustainable practices in pig production are demanding.•Differences of environmental performance, depending on reproductive indicators.•Greenhouse gas emissions can be included in sow yield calculation.•Feed quality and nonproductive days impact environment. Animal production influences the environment through land-use changes and the cycle of nutrients such as CO2. Pork production is an essential sector of agribusiness nowadays. This type of farming will also be affected by climate change since the production of animal feeds depends on the weather. New information on pork production is vital to study the amount of feed wasted through sow yield and environmental inefficiency on farms. Many sow indexes have been used in the last years, especially addressing reproduction efficiency. However, there is a lack of research on production losses from Greenhouse Gas emissions. The aim of the assessment was to estimate the daily feed intake of sows and the amount of feed consumed during their nonproductive days, correlating these results to greenhouse gas emissions. The variables were analyzed by the Life Cycle Assessment tool at Tier 3 level. The physiology of metabolic digestion related to sow respiration was calculated for each life stage. There were six Brazilian scenarios: 1 and 2 – farms from the Midwest region; 3 to 6 – different piglets systems from all regions. Producing piglets with 6.0 to 10.0 kg requires much time and feed intake, and feed processing depends on natural resources. Daily feed intakes during nonproductive days corresponded to 16,315.30 tons of total feed intake/year. Each scenario showed different results. For instance, Scenario 1 emitted 2.80 kg of CO2eq./kg of piglet, and Scenario 4 emitted 3.89 kg of CO2eq./kg of piglet. The environmental impacts analyzed lead us to conclude that the Brazilian production can be more efficient. Nonproductive days were harmful for weaned piglet production as the total feed intake of sows correlate with born alive and weaned piglets. Greenhouse Gas emissions can be included in sows yield calculation.