Ram scrapie score

21 August 1998

Ram scrapie score

RAMS for sale this autumn will be assigned a score of one to five to indicate risk of contracting the disease or passing it onto progeny.

Set up by the Scrapie Information Group (SIG), the system will help breeders identify susceptibility of individual sires to prospective purchasers, easing interpretation of complex genotyping, it says.

A score of R1 indicates a very low risk of scrapie in individual sheep and low risk in first generation progeny, while R2 means a low risk in the individual and first generation progeny. A score of R3 means a low risk in the individual but some progeny may be at risk depending on the genotype of the other parent. R4 indicates that scrapie may be occasionally recorded in the genotype, and a higher proportion of progeny of these sheep is likely to be at risk compared with the progeny of R3 sheep. Rams at greatest risk of scrapie are assigned as R5.

The SIG stresses that interpretations of gene classes based on probability and not certainty. Figures will be reviewed regularly and modifications made if necessary. It also emphasises that breeders must keep potential scrapie risk in perspective and evaluate all breeding and production considerations.

"Producers must realise that there is little to be gained from having a flock at low risk of scrapie if other important commercial attributes are sacrificed," it advises.

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