Brief skin structure and some coat characteristics of sheep breeds in halayeb, shalateen and abou ramad triangle, in two seasons

Abstract EN

The present study was undertaken to investigate the effect of two seasons of the year, summer and winter, on the morphology and structure of the different skin components of three sheep breeds; Kanzi, Maneit and Aboudeleik.

The study was carried out on thirty adult ewes in Hederbah valley, Halayeb AND Shalateen Research Station, belonging to Desert Research Center.

The station lies at 1400 km to the south east of Cairo.

Sheep skin consists mainly of epidermis and dermis.

The epidermis composed of stratified squamous keratinized epithelium and its thickness differed significantly according to different breeds.

The dermis consists of connective tissue which is divided into an upper papillary layer and a lower reticular layer.

An opposite trend to that exhibited by the dermal average thickness was observed in relation to coarseness.

The histological measurements taken for the sweat glands showed that there were significant differences between the three breeds and that the size increased significantly in summer season in comparison with winter season.

Secondary to primary follicle ratio (S /P ratio) was affected significantly by both breed and season.

The structure of the wool follicle in the sheep skin revealed that it consisted of outer root sheath and inner root sheath which could be divided in Henle’s layer, Huxley’s layer and cuticle.

There was an increase in the external and internal diameters of both primary and secondary follicles from summer to winter.

While follicle wall thickness showed a noticeable decrease in summer irrespective of follicle types.

Generally, seasons affected fibre diameter where the highest diameter was found in summer.

The relative width of the medulla increased with increasing fibre diameter.

The coat fibres in the three breeds were of bimodal structure consisting of outer and under coats.

The outer coat percentage in the fleece increased significantly in summer season.

The kemp and Atype fibres were found to have higher percentages than those of type B and C in the outer coat of different breed fleeces at different seasons for all body positions studied.

Aboudeleik breed had the highest percentage of the under coat fibres.

Whereas, the dorsal body positions had greater amounts of the under coat fibres than those of the lateral positions.

In all breed groups there was a significant increase in the under coat fibre length from summer to winter.

The number of crimps/cm in the under coat fibres was significantly higher in winter season.