Abstract #97

# 97
Technical and economic performance of Holstein crossbred versus pure Holstein herds using a stochastic simulation model.
M. López-Suárez*1, L. Castillejos1, M. Piera2, J. M. Loste3, S. Calsamiglia1, 1Department of Animal and Food Sciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain, 2Centre Veterinari Tona, Tona, Barcelona, Spain, 3Albaikide, Irurtzun, Navarra, Spain.

Crossbreeding can be used as an approach to counteract the negative effects of inbreeding within Holstein herds and to improve functional traits such as fertility, calving ease, health and survival of cows. The objective of this study was to compare the productive and economic performances of pure Holstein (H) with Holstein crossbred (C) herds using a stochastic dairy farms simulation model (www.dairyfarm.es). Data from 3 farms with a subpopulation of pure Holstein and a subpopulation under a crossbreeding program, with the same feeding and management systems, were used for the simulation. Thus, using performance data of each subpopulation, within each real farm, 2 sub-herds were generated in the simulator: an H herd and a C herd. The same average economic conditions were used in the 3 farms. Results were obtained from simulations of a 4-year period. The C herds had higher fertility (7 to 10 percentage units), fewer days open (24 to 32 d), more calves born and lower milk production (1.4 to 2.3 L/d/cow) compared with H herds. Moreover, the C herds had lower feed and reproduction costs, lower milk sales revenues and lower income over feed costs compared with H herds in the 3 farms. The gross margin adjusted for the animal inventory was higher in H than in C herds in 2 of the 3 farms studied (+€136 and +€264/cow/year) due to higher milk production and revenues. In the third farm, the difference in gross margin was slightly higher in C than in H herd (+€12/cow/year), due to the penalty for the high SCC in H (average of 310 and 524,000 cells/mL for C and H, respectively), which decreased the milk price, and the smaller difference in milk production between H and C herds (1.4 L/d/cow) compared with the other 2 farms, where the difference in milk production was larger (2 and 2.3 L/d/cow). Results suggest that the improvement in reproductive performance of crossbreeding does not compensate for the lower milk production of crossbred herds.

Key Words: crossbreeding, milk production, economics