RESUMO
Seventy-five pairs of ovaries from Yankasa Sheep aged 1 1 2 to 3 years were collected from a Zaria abattoir for 12 months, to study the ovarian activity. It was observed that ovarian activity in Yankasa sheep was year-round with maximum activity occurring during the rainy and pre-rain seasons. These periods of maximum ovarian activity might be caused by the availability of pasture during the rainy and pre-rain seasons, since Nigerian sheep obtain most of their food by grazing available pasture.
RESUMO
The histological structure of the oesophagus of the camel in different parts of its course was investigated with tissues from seven camels, and with haematoxylin and eosin and Masson's trichrome stain. Gross dissections confirmed the orientation of the muscle fibres in the tunica muscularis. The epithelium showed heavy cornification. Many submucosal mucous glands were found throughout the length and all round the wall of the oesophagus. This was contrary to what has been reported generally for ruminants. The lamina muscularis mucosae was in the form of small scattered strands of smooth muscle (more readily identifiable with trichrome stain) and only in the caudal oesophagus. It did not form a continuous layer here. The tunica muscularis was of striated type throughout which agreed with what has been found in the other ruminants. Its fibres, however, were differently oriented. The outer tunica was mainly circular (especially in the mid-thoracic part) and the inner one was mainly longitudinal in direction. Mixed orientation of the muscle fibres in parts of the same section was also noticed. These findings have not been reported previously in the camel.
