The morphological postnatal development of the testis of the Nubian bucks.

This study was designed to monitor the morphological development of the reproductive tract of the Nubian bucks in relation to puberty. Thirty-two Nubain male kids were used in the study. The animals were slaughtered at intervals of 2 weeks starting from 1 day old up to 24 weeks of age. Tissue samples were obtained from the testes and processed for ultrastructural studies. The boundary tissue of the newly forming seminiferous tubule adhered closely to the basal lamina. It consisted of a single continuous layer of myoid cells, the outer surface of which was covered by scattered fibroblasts. The ultrastructural study of the boundary of the seminiferous tubule revealed that it consisted of three layers; inner fibrous, middle and outer cellular. The seminiferous tubules at week one were lined by two layers of epithelia; spermatogonia and Sertoli cells in the basal layer, and primary spermatocytes in the second layer. A gradual increase in the diameter of the tubules and epithelial height continued to increase with age. Furthermore, spermatocytes number showed an increase with age. In conclusion, based on the appearance of spermatozoa in the lumina of the seminiferous tubules, puberty age was achieved between weeks 18 and 20.

Thermoregulation and reproductive performance of grazing desert ewes (Ovis aries) as influenced by concentrate supplementation.

Twenty sexually mature Desert ewes were used to study the effects of concentrate supplementation on thermoregulation and reproductive traits. The ewes were divided into two equal groups, control and supplemented; the supplemented group received daily 500 g of concentrate mixture (crushed sorghum grain and cotton seed cake). In both groups, oestrus was synchronized with hormonal method and the ewes were naturally inseminated. Pregnancy was diagnosed by the ultra-sonography technique. Dietary supplementation resulted in a shorter time of oestrus onset, higher rates of conception, lambing and a significant decrease in gestation length. The fertility and fecundity of ewes were also improved. Supplementations also increased significantly the pre-and post lambing weight of ewes and the birth and weaning weights of the lambs. The body weight, rectal temperature and respiratory rate increased significantly with the advance of pregnancy in both groups of ewes. These indices decreased significantly with the progress of lactation. The supplemented ewes maintained higher values of these indices during pregnancy and lactation.