NR ASIW
AU Chase-Topping,M.E.; Kruuk,L.E.; Lajous,D.; Touzeau,S.; Matthews,L.; Simm,G.; Foster,J.D.; Rupp,R.; Eychenne,F.; Hunter,N.; Elsen,J.M.; Woolhouse,M.E.J.
TI Genotype-level variation in lifetime breeding success, litter size and survival of sheep in scrapie-affected flocks
QU Journal of General Virology 2005 Apr; 86(4): 1229-38
PT journal article
AB Five different sheep flocks with natural outbreaks of scrapie were examined to determine associations between individual performance (lifetime breeding success, litter size and survival) and scrapie infection or PrP genotype. Despite different breed composition and forces of infection, consistent patterns were found among the flocks. Regardless of the flock, scrapie-infected sheep produced on average 34 % fewer offspring than non-scrapie-infected sheep. The effect of scrapie on lifetime breeding success appears to be a function of lifespan as opposed to fecundity. Analysis of litter size revealed no overall or genotype differences among the five sheep flocks. Survival, however, depends on the individual's scrapie status (infected or not) and its PrP genotype. Susceptible genotypes appear to perform less well in lifetime breeding success and life expectancy even if they are never affected with clinical scrapie. One possible explanation for these results is the effect of pre-clinical scrapie. Additional evidence supporting this hypothesis is discussed.
MH Animals; Breeding; *Disease Outbreaks; Female; Genotype; Litter Size; Prions/*genetics; Research Support, Non-U.S. Gov't; *Scrapie/epidemiology/genetics/mortality; Sheep Diseases/epidemiology/genetics/mortality; Sheep, Domestic/metabolism/*physiology; Survival Rate; *Variation (Genetics)
AD Centre for Tropical Veterinary Medicine (CTVM), Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK. margo.chase@ed.ac.uk
SP englisch
PO England