Economic values for performance and functional traits in dairy sheep

Abstract

In order to establish a total merit index, the relative economic values of the traits considered must be known. Hence, the objective of this study was to derive economic values, defined by the value of one unit of superiority of a trait, for essential traits in dairy sheep based on a herd model. These traits included dairy (milk carrier = water, lactose and mineral nutrients, fat and protein yield), fattening (daily gain, dressing percentage, and EUROP grading score) and functional traits (stillbirth rate, losses until first mating, litter size, lambing interval, and functional longevity). To avoid double counting, the economic value for each trait was derived while keeping all other traits constant. A sheep herd with milk production, lamb fattening and rearing of young sheep for replacement was modelled. The following economic values (in €) per ewe place and year and genetic standard deviation were derived: 21.45 (milk carrier yield), 11.73 (fat yield), 16.87 (protein yield); 3.62 (daily gain), 1.62 (dressing percentage), 1.45 (EUROP-grading score), -0.28 (functional longevity), 3.00 (litter size), 1.77 (stillbirth), 5.92 (losses before first mating), and 5.35 (lambing interval). When setting functional longevity to zero, relative economic values for the trait complexes in % were as follows: dairy:meat:functional traits = 68.8:9.2:22.0, respectively.