Environmental footprint of Holstein and crossbred cows using an individual LCA-derived method

This study aimed at assessing the effects of a 3-breed crossbreeding program on the environmental footprint of individual dairy cows (Life Cycle Assessment, LCA, method). Data concerned 564 cows, 279 purebred Holstein (HO) and 285 crossbreds (CR), originated from a 3-breed crossbreeding program (PROCROSS) based on the rotational use of Viking Red, Montebèliarde and HO sires and kept in two dairy herds of northern Italy (224 and 340 cows/herd, respectively). The reference unit of the LCA model was the lifespan of cows (from the birth to the farm-gate). Data were collected at different levels: individual animal-based data referred to the whole life (birth, calving, dry and cull dates, milk production); individual test-date collection of body measures and BCS, used to predict body weight and to estimate energy requirements; common farm-based data concerning herd management (diets composition, materials used). Data were used to compute or estimate dry matter intake, milk and milk components production, gross income (GI) and income over feed costs (IOFC) pertaining to the whole career of cows. Impact categories assessed were global warming (GWP), acidification (AP) and eutrophication (EP) potentials. Different functional units (cow; d of life; kg of milk; kg of fat + protein; € of gross income and IOFC) were used. Data were analysed using GLM including the fixed effects of farm, genetic line (CR vs HO) and their interaction. Compared to HO, CR completed more lactations (+12%), had earlier first calving (-2%), produced less milk per day of production (-3%), but more fat plus protein per d of life (+ 4%), and tended to provide a greater IOFC (+7%). Moreover, compared to HO herdmates, CR tended to have greater GWP per cow in the whole life, similar GWP per d of life and 4% lower GWP per kg of fat plus protein produced in the whole life (P=0.07). Also GWP per € GI tended to be lower (-3%) in CR compared to HO cows. Managing dairy cows within the crossbreeding scheme may therefore contribute to mitigate emissions of GHGs in dairy operations.