PUBERAL DEVELOPMENT IN THE NIGERIAN DWARF SHEEP

Age and body weight at puberty in ewe lambs

Abstract

THE Incidence of the first behavioural oestrus (puberty) in 28 ewe lambs was investigated to determine the effect of the plane of nutrition on it. The ewes were randomly alloted and reared on two planes of nutrition: one exclusively on roughage (grazing and bay) the second roughage supplemented with concentrate at the rate of 454g a day from weaning to puberty.
The ewe lambs were checked for standing heat with two vasectomised rams twice daily - mornings and evenings. The age and body weight at puberty and the average daily gain from weaning to puberty In unsupplemented ewes were 339.5 ± 7.8 days, 14.6 ± 0.9kg and 29.4 ± 4.7g respectively. The corresponding figures for the supplemented ewes were 262.0 ± 16.2 days, 16.2 ± 0.7kg and 73.0 ± 6.6g. The ewe lambs born as singles attained puberty at a younger age but lambs fed supplemented concentrate ration had a significantly higher growth rate and attained puberty at a significantly younger age and higher body weight than ewe lambs fed on roughage only. The durations of early postpuberal oestrus and oestrous cycle were 41.03 ± 2.94 hours and 18.00 ± 0.63 days respectively.