Abstract :
A deterministic static model was used to estimate the economic values (EV) of production
(MY, milk yield; BW, birth weight; and ADG, average daily gain) and functional traits (ASR,
adult survival rate; LSR, lamb survival rate; FE, fertility; PR, prolificacy; and LWewe, mature
weight of ewe) in Valle del Belice dairy sheep. In this study, values for the biological parameters
and the production traits used in the model were taken from real data, by surveying
15 Valle del Belice farmers and reflected the production circumstances of pasture based
dairy production systems. In this system feed cost accounted for 95% of total variable costs,
whereas fixed costs were low and reflected traditional and small ruminants’ husbandry
system. A base situation with a fixed number of animals was considered to estimate the EV
for the traits considered in this study. Economic values were positive for production traits:
D 0.31 (MY, kg), D 4.40 (BW, kg) and D 0.15 (ADG, g) and for functional traits: D 2.15 (ASR,
%), D 0.78 (LSR, %), D 2.64 (FE, %), D 0.39 (PR, %), except forLWewe that was negative (D −0.08,
kg). Sensitivity analysis of EV to changes in prices indicated that future economic values
for traits might change dependent on output and price levels, in particular on milk and
meat price level. This study suggests that genetic improvement of milk production, lamb
and adult survival rate, fertility and prolificacy will have a positive effect on profitability of
pasture based dairy production system.
