The Spatial Relationships Between Skin Follicles During Their Development in Sheep

Abstract

The spatial relationships among primary skin follicles and among the total skin follicle population have been measured and compared during follicle initiation and development in fetuses of Romney X Southdown cross and Merino sheep. There was no evidence suggesting that the distribution of primary follicles is different between the two breeds and the number of secondaries that develop is evidently independent of any influence the pattern of primary follicles may have on the pattern of secondary follicle initiation. After primary follicle initiation is complete, movement of lateral primaries away from their corresponding central primary is greater than that resulting from a uniform expansion of the skin. After the commencement of secondary initiation changes in the distribution of all follicles are dependent on the S/P ratio. The tendency for an aggregated follicle distribution to result from localized secondary initiation between the primaries in each follicle group is to a large extent counter-balanced by a differential movement of the secondaries away from the primaries.