Sheep Scrapie Genetics and Welfare Implications

Scrapie is a fatal prion disease of sheep causing progressive neurological degeneration. Genetic resistance programmes offer a path toward eradication through selective breeding.

Key Facts

Scrapie has been present in UK sheep flocks for over 250 years and remains endemic in many areas
The disease is caused by misfolded prion proteins that accumulate in the nervous system
Affected sheep show characteristic rubbing, incoordination, altered behaviour, and progressive weight loss
The PrP gene has variants conferring different levels of scrapie resistance — the ARR/ARR genotype is most resistant
The National Scrapie Plan promoted breeding from ARR rams, substantially reducing disease incidence
Classical scrapie is not considered transmissible to humans, but disease-free flocks protect trade and farm welfare

Welfare Considerations

Scrapie causes progressive neurological deterioration that is distressing and undignified. Affected sheep gradually lose coordination, spend increasing time rubbing and scratching, and experience wasting without any effective treatment available. Genetic breeding programmes that increase resistance genotypes represent a preventive welfare strategy that benefits both individual animals and flock-level welfare across the industry.

What You Can Do

Support and participate in voluntary scrapie genetic resistance testing programmes
Discuss PrP genotyping with your vet or breed society when selecting breeding rams
Report suspected scrapie cases promptly — statutory reporting is required in the UK
Support research into prion disease mechanisms and eradication strategies
Join breed societies committed to scrapie resistance programmes within their populations
Include scrapie resistance status in breeding records and pedigree information