Breed structure and genetic analysis of Border Leicester sheep

Abstract

Since the year 1900 the number of Border Leicesters has been fairly stable, between 3,000 and 5,000 females being registered each year. The number of flocks, however, has shown a fairly steady increase from 200 to over 600. There has been a decline in the number of ewes registered per flock from 16 to about 6 to 8. The important flocks would seem to number 15 to 20; only a few flocks persist for any appreciable length of time. Generation intervals are short, being only about 2 years on the sire side and 3½ years on the female side.As with other breeds, relatively few rams have an importance out of proportion to their numbers—14 rams and 2 ewes with direct coefficients of relationship greater than 5% were found. Inbreeding per generation was only 0·32%, and there was no evidence of strain effects.