A stochastic model for the derivation of economic values and their standard deviations for production and functional traits in dairy cattle
Nielsen, H.M. ; Groen, A.F. ; Ostergaard, S. ; Berg, P. - \ 2006
Acta Agriculturae Scandinavica Section A-Animal Science 56 (2006)1. - ISSN 0906-4702 - p. 16 - 32.
feed-intake capacity - selection indexes - production circumstances - profit-functions - breeding goals - herd - bias
The objective of this paper was to present a model of a dairy cattle production system for the derivation of economic values and their standard deviations for both production and functional traits under Danish production circumstances. The stochastic model used is dynamic, and simulates production and health in a dairy herd. Because of indirect effects between traits, the phenotypic levels of (related) traits can change as a result of genetic changes. Economic values for milk production and body weight were 0.28 and -0.76 euro/kg per cow-year respectively. For incidence of milk fever, mastitis, retained placenta and laminitis economic values were -402.1, -162.5, -79.0 and -210.2 euro/incidence per cow-year. The economic values for involuntary culling rate, stillbirth and conception rate were -6.66, -1.63, and 1.98 euro/% per cow-year, respectively and the economic value for days from calving to first heat was -0.94 euro/day per cow-year. Standard deviations of economic values expressing variation in realised profit of a farm before and after a genetic change were computed using a linear Taylor series expansion. Expressed as coefficient of variation, standard deviations of economic values based on 1000 replicates ranged between 0.07 (milk production) to 16 (retained placenta)
Definition of a breeding goal for the Piemontese breed: economic and biological values and their sensitivity to production circumstances.
Albera, A. ; Carnier, P. ; Groen, A.F. - \ 2004
Livestock Production Science 89 (2004)1. - ISSN 0301-6226 - p. 66 - 77.
beef-cattle production - production traits - livestock production - output limitations - genetic-parameters - selection indexes - profit equations - carcass traits - objectives - efficiency
Economic values have been derived for the Piemontese breed using a bio-economic deterministic model that simulates an integrated beef cattle enterprise. Investigated traits were post-weaning daily gain (DG), live fleshiness scores (FLESH) that are related to the market value of animals for slaughter, calving ease in the first (CEh) and later parities (CEc) and calving interval (Q. Economic values, calculated using a fixed number of cows per herd as a basis of evaluation and expressed in Euro per cow per year, were 0.20 per g/day for DG, 57.01 per point for FLESH (measured with a linear scoring system in nine classes), - 2.60 per day for Cl. For calving ease economic values per a 1% increase in the liability scale were 0.57Euro in the first and 1.99Euro in later parities, respectively. The economic value of the studied traits showed moderate dependence on trait levels. Production circumstances poorly affected the estimated economic values with the exception of energy input and live weight output limitations that markedly decreased the economic values of all traits but FLESH. Biological values, reflecting improvement in efficiency in energy utilization, corresponded well in relative size to economic values in most of the considered traits. (C) 2004 Elsevier B.V. All rights reserved.