Environmental Impact assessment of a semi-intensive beef cattle production in Brazil’s Northeast

The aim of this study is to identify and evaluate the main environmental impacts related to semi-intensive beef cattle production system in the State of Bahia, in Brazil’s Northeast.

A cradle to gate study was undertaken in a beef cattle production system comprising two stages: calves production in one farm (farm 1) and cattle production in another farm (farm 2), both located in the central-southern meso-region of Bahia. The functional unit was 1 kg live weight. Impact assessment was performed using five impact categories from the ReCiPe method.

When compared to calves, the cattle production had the greatest contributions in all of the five studied impact categories. The process pasture cultivation had expressive environmental impacts in all categories, with 70.05 % for climate change (CC), 82.01 % for terrestrial acidification (TA), 76.53 % for fossil depletion (FD), 86.14 % for freshwater eutrophication (FE) and 100 % for agricultural land occupation (ALO). In CC and TA, the principal elementary flow was the direct emissions due to the use of mineral fertilizers. In FE and FD, the dominant flow was related to the use of phosphate fertilizer. In ALO, the process pasture cultivation was predominant due to the physical area of the farms, which is a characteristic of pasture-based production systems. The processes breeding-rearing and fattening were second in the contribution analysis, with 29.95 % and 17.99 %, respectively, for CC and TA, due to the enteric methane (CH₄) and the direct emissions of nitrous oxide (N₂O) volatilization from the animal excreta.

The cattle production is responsible for the greater part of impacts, compared to the calves production. The direct emissions from fertilizers used in the pastures, from enteric emissions and from animal wastes in the breeding-rearing and fattening processes were identified as the critical points of the analysed cattle production system. Measures aiming at the improvement of the feed conversion of the animals and at the substitution of synthetic nitrogen fertilizers by natural nitrogen fixation can considerably contribute to the reduction of environmental impacts of these production systems. Accordingly, the respective modifications should be considered in future studies on the potential of these measures to enhance the environmental performance of semi-intensive beef cattle production. These results will complement other similar studies conducted in other regions of the country, following the tendency of growing usage of the life cycle assessment methodology in Brazilian agricultural and livestock systems.