Relationship Between Cyclic Changes in the Hair Follicle and Sweat Gland Size in Cattle

Abstract

SummaryThe morphology of hair follicles has been studied in 23 Africander-Hereford crossbred yearlings. Eleven hair growth phases were recognized as a result of work on two animals. The piloapocrine units representing each phase have been illustrated by tracings. The mean length, diameter, length-diameter ratio, and area of sweat glands corresponding to each phase have been tabulated and illustrated.Gland size was very significantly influenced by follicle phase. Glands were largest in anagen VI and catagen c and were completely regressed in telogen.The effect of differences in follicle phases on sweat gland size was studied in all 23 animals. The inherent difference between animals in gland size was determined by a comparison of mean gland size for common phases. Actual mean gland size is also influenced by frequency of the various follicle phases. In the present study the contributions of inherent differences and differences due to phase distribution were in the ratio of 3·2: 1.Although doubt is cast on sweat gland morphology as the sole criterion of sweat gland activity, the association between hair growth phase and sweat gland size offers a partial explanation of the association between coat character, sweat gland size, and sweat gland activity. These three are found to vary together when comparisons are made between breeds or strains, between animals within breeds, between different body regions, and between seasons.

Swat Glant and Hair Follicle Measurements as Indicators of Skin Type in Cattle

“…However, although seasonal changes occur in most of the skin parameters, sweat gland shape appears to be independent of seasonal variation. Schleger (1966) from a study of two animals maintains that in cattle the sweat glands undergo cyclic changes in morphology in association with the hair-growth cycle and completely disappear during the telogen or resting phase of the hair. These findings are not substantiated by the present experiments in which full-sized sweat glands were observed associated with hair follicles in all stages of the hair cycle in all instances where the gland was complete and undamaged by cutting and processing.…”

Ectodermal Dysplasias in Cattle.

“…In cattle, congenital and hereditary abnormalities of the skin have been clinically studied with a degree of thoroughness approaching that in man. Background information on the norinal embryogenesis and cyclic changes of the cutaneous appendages of cattle can be obtained from the articles by Hayman (1965) and Schleger (1966). Kaiowledge of hereditable infirmities assumes considerable economic and eugenic importance in cattle for the purpose of inbreeding herds.…”