Sources of variation of the environmental impact of cereal-based intensive beef finishing herds

Abstract

This study aimed to investigate the effect of beef category, feedstuffs self-sufficiency (SELF), crude protein (CPI) and phosphorus (PI) daily intake on the environmental impact of the beef fattening system typical of north-eastern Italy according to a partial Life Cycle Assessment. The reference unit was the batch (group of animals homogeneous for genotype, sex, fattening farm, finishing period). The study involved 245 batches (64 ± 34 heads) herded in 17 fattening farms. The system boundaries were set from animals arrival at the fattening farm to the sale to the slaughterhouse. The functional unit was 1 kg BW gain (BWG). Data on animal performance and farm input were collected for each batch and farm, respectively. Data on feed intake, ingredient formulation and chemical composition of diets were monthly collected for each batch. Impact categories assessed were (mean ± SD per kg BWG in brackets): global warming (8.8 ± 1.6 kg CO2-eq), acidification (142 ± 22 g SO2-eq) and eutrophication (55 ± 8 g PO4-eq) potentials, cumulative energy demand (53 ± 18 MJ), land occupation (7.9 ± 1.2 m2/year). Beef category and SELF, CPI and PI classes significantly affected all the impact categories, with lower values observed with decreasing values of CPI and PI and increasing values of SELF as well as more productive beef categories. This study evidences that beef category and diet-related factors affect the environmental impact of cereal-based intensive beef finishing herds. In conclusion, there is space to develop mitigation strategies based on enhancing the self-sufficiency rate of the diet and lowering the daily intake of crude protein and phosphorus.