EFFECT OF SUPPLEMENTARY FEEDING ON SHEEP SKIN AND COAT CHARACTERISTICS IN HALAIEB, SHALATEEN AND ABOU RAMAD TRIANGLE

Fifteen adult local ewes aged 2-4 years with an average body weight of 30 kg were employed to study the effects of grazing and supplementary feeding on wool follicles activity. Animals were randomly divided into three equal groups. The first group was kept in confinement (control, group 1) and fed on clover hay supplemented with concentrate feed mixture (1% of BW), while the other two groups (2 and 3) were grazing the natural rangelands and supplemented with the same concentrate mixture (1 or 2% of BW, respectively). Animals raised in Hederbah valley, Shalateen Research Station from July 2013 to April 2014. At the end of the experiment, skin samples were taken and used to examine the follicle activity and their fibres in response to grazing and supplementary feeding. Results revealed that there is a significant increase in various primary follicle dimensions and their fibres of animals having the supplementary feeding with the double amount of concentrate except in the wall thickness which decreased significantly in all treated animals in comparison with the control group. The increase in the internal diameter of the follicles accompanied by a decrease in the follicles wall thickness was in relation to the increased values of the fiber diameter. Medulla thickness also showed an increased value by the double supplementary feeding. Grazing process showed a significant decrease in the external diameter and wall thickness of the primary follicles and in all secondary follicle dimensions in animals having 1% from body weight concentrate mixture in comparison with the control group. On the other hand, supplementary feeding level by 2% from body weight concentrate mixture showed a slight increase in all secondary follicle dimensions and their fiber diameters in comparison with the other grazed group. Histochemically, there is an excess protein and carbohydrate content in the outer root sheath of both primary and secondary wool follicles than that in the inner root sheath. Administration of double amount of concentrate resulted in a significant increase in the protein content in both sheaths of the primary follicles. An intermediate content was observed in the grazed group having concentrate 1% from body weight. The general carbohydrates showed a reversible trend and the intermediate value was detected in the control group. In secondary follicles, free grazing revealed a non significant decrease in the general protein contents in both follicle sheaths while the general carbohydrates showed an increase in grazed animal than the control group and in the supplemented group than the other two groups. Generally, the supplementary feeding increased the activity of the primary and secondary wool follicles and consequently the wool production and reduced the effect of grazing process.