Evaluating different PrP genotype selection strategies for expected severity of scrapie outbreaks and genetic progress in performance in commercial sheep.

Abstract Stochastic computer simulations were used for quantifying the effect of selecting on prion protein (PrP) genotype on the risk of major outbreaks of classical scrapie and the rate of genetic progress in performance in commercial sheep populations already undergoing selection on performance. The risk of a major outbreak on a flock was measured by the basic reproduction ratio ( R 0 ). The effectiveness of different PrP selection strategies for reducing the population risk was assessed by the percentage of flocks with R 0