Comparison of Skin Follicle Populations between Breeds, between Breeds and F1 Crossbreds and between F1 Crossbreds of Sheep.

This study was carried out to compare skin follicle populations, which are the foundation of wool producing ability, betwen breeds(Corriedale, Suffolk and Border Leicester), between F1 crossbreds(Corriedale♂　×　Suffolk♀ and Corriedale♂　× Border Leicester♀) and their parental breeds and between F1 crossbreds(Corriedale♂ × Suffolk♀, Corriedale♂ × Border Leicester♀ and Corriedale♂ × Southdown♀) of sheep. As experimental animals, casrated ram lambs in 4-5 months of age were used and histological sections of skin sampled from the mid-side region were prepared and comparison of mean number of total follicles(nx+s), primary follicles(np) per sq. mm. and secondaries(ns) per primary(np) were made between breeds, between F1 crossbreds and their parental breeds and between F1 crossbreds. The results obtained were as folllows: (1)The mean total follicle number per sq. mm. skin area of Corriedale breed was largest among 3 breeds of sheep, that of F1 crossbreds intermediate between those of their parental breeds and the difference of mean total follicle numbers between F1 crossbreds small. (2)The differences of mean primary follicle numbers per sq. mm. skin area between breeds, between F1 crossbreds and their parental breeds and between F1 crossbreds were comparatively small. (3)The Mean numbers of secondary follicles per primary follicle between breeds, between F1 crossbreds and their parental breeds and between F1 crossbreds showed a similar trend to those in the mean total follicle number.