Abstract

This study was carried out at the National Sheep Research Station in Elhuda, Sudan to investigate the situation of female sheep conditions while in gestation and to consult some aspects associated to pregnancy parameters and others on live weight were collected, processed and statistically tested in addition to variability consideration. Thus, live weight changes its variability and some relationships for certain reproductive traits in the Shugor and Dubasi subtypes of Sudanese Desert sheep ewes were studied from mating events to the immediate postpartum date. The overall live weight changes during this period resulted in an increase of 22.8 and 27.6% in the live weight of either of these two ewe groups ,respectively, but with an overall greater in live weight variability within the Shugor as contrasted with that within their contemporary Dubasi ewe group (11.33vs 8.27%, CV), having periodic mean value which ranges from 10.70 -13.5% CV and 7.2 – 8.5% CV, respectively, for the Shugor and Dubasi ewe groups. The combined contribution of the foetal lamb weights, foetal placenta fluids weights composed 20.0% for the Shugor and 17.9% for the Dubasi of the breeding (mating) live weight of each while the weight of the lamb at birth and that of the associated placenta had mean values of 11.1 ±0.06% and 1.23 ± 0.06, respectively, of the Shugor pre-partum ewe live weight but the corresponding mean proportional values in the Dubasi group were 9.48 ± 0.49% and 1.20 ±0.08 % .The regression of gestation length, post-partum ewe live weight and lamb birth weight had mean values of + 0.37 , + 0.71 and 0.002 as related to the breeding (mating) ewe live weight of the Shugor whereas the corresponding regression values in the Dubasi ewes were +0.03 ,+ 0.67 and + 0.03. None of these contrasting parameter values was significantly different in the two subtype groups. Similarly, the regression values of the placenta weight on the lamb birth weight were not significantly different, respecttively, - 0.02 and + 0.032 in the Shugor and Dubasi ewe groups. It is concluded that live weights variations in breeding females should be made manageable to their least possible to allow for more solid data, on the female and its offspring, as this is conductive to performance development.