PUBERAL DEVELOPMENT IN THE NIGERIAN DWARF SHEEP

Absolute and relative organ growth in the ram lambs

Abstract

Eleven ram lambs, all born between June and July (rainy season) were slaughtered at four age groups — 75, 100, 125 and 150 days. The body weights of animals prior to slaughter, the weights of the testes, the epididymis, the vesicular glands, the ampullae, the adrenals, the thyroids and the pituitary glands were determined and subjected to a step-wise multiple regression analysis using age or body weight as the independent variable. The weights of the reproductive organs – testes, epididymides, ampullae, vesicular glands - showed significantly higher correlation with the body weight than with the age, thus emphasizing the greater importance of the physiological age over the chronological age in the development of the body organs. The highest growth rate of the organs of the reproductive tract occurred during puberty and thus coincided with the enhanced endocrine function observed in ram lambs at this stage.