Influence of Season of Lambing on Postpartum Interval to Ovarian Activity in Djallonke Ewes
Salifu S.* Avornyo F. K. Panyan E. K. Hagan B. A.
Vol 8(8), 50-61
This study was conducted to estimate the influence of season of lambing on the postpartum interval to return of ovarian activity, conception and subsequent lambing (lambing interval) among 78 Djallonke ewes reared on-station in the Guinea Savannah zone of Ghana. Serum progesterone measurements were used to determine the postpartum return to ovarian activity for ewes lambing in two major seasons; the rainy and dry seasons. The results showed that Djallonke ewes resumed ovarian activity 63.7±2.7 days postpartum and conceived by 97.4±4.2 days postpartum, achieving a mean lambing interval of 249 days. Ewes lambing in the rainy season resumed postpartum ovarian activity significantly earlier than their counterparts lambing in the dry season (55.1±4.1d vs 71.5±3.2d, respectively) (P<0.001). The mean time to conception for ewes lambing in the rainy season was shorter (85.0±6.7d) compared to ewes lambing in the dry season (109.1±4.6d) (P<0.001). The ewes lambing in the rainy season also had shorter lambing intervals compared to ewes lambing in the dry season (237.2±6.8d vs 261.5±4.7d, respectively) (P<0.001). While ewes lambing in the dry season tended to lose weight over the lactation period (-1.1±0.3kg), ewes that lambed in the rainy season experienced a significant net weight gain (0.8±0.2kg) (P<0.001). It is concluded that season of lambing significantly affects the length of time to return of oestrus among postpartum Djallonke sheep, with rainy season lambing being more favourable to achieving early resumption of ovarian activity, conception and shorter lambing intervals.
Keywords : ELISA Ghana Guinea Savannah Progesterone Season West Africa Dwarf Sheep
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