Hair follicle group and skin follicle population of Australian Merino sheep

Abstract

Skin specimens from 495 Australian Merino ewes were collected from 22 flocks, including 9 parent studs out of the 17 identified in the contemporary population. Flocks from all of the 4 important strains of the Australian Merino are represented. The skin samples were collected by a standard biopsy method devised for the purpose by the authors, and histological sections prepared. The techniques are described and data for the following estimations presented: mean total (np+z) follicle population density; mean primary (np) follicle population density; ns/np ratio; mean primary (dp) fibre diameter; mean secondary ( da ) diameter; mean fibre diameter of the composite population (dp+s); mean ratio of primary and secondary fibre diameters (dp/ds). For each flock the mean and standard error of the estimations are tabulated and the range of individual values observed summarized for each of the four Merino strains. The data are presented as the material on which further more detailed analyses will be made; the need is stressed for extending these studies, which form an important basis for genetic studies of fleece structure in the Merino and other breeds. Attention is also drawn to certain extreme variants in the hair follicle group, one of which (a very small group) may prove to have a simple hereditary origin.