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Turkish Journal of Veterinary & Animal Sciences

DOI

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Abstract

The present study investigated the effects of double injections of PGF_{2}\alpha at different intervals (10 vs. 14 days) on plasma progesterone levels, oestrus and lambing rates in Tuj ewes during the breeding season. Thirty clinically healthy mature ewes were assigned randomly into 2 experimental groups: 2 injections of 125 µg of Cloprostenol (a PGF_{2}\alpha analogue) at either 10 (Group I, n = 15) or 14 day (Group II, n = 15) intervals. Blood samples were collected from the jugular vein on the day of the second injection of PGF_{2}\alpha, 4 days post-injection and 16 days after insemination to determine plasma progesterone levels. The oestrus and lambing rates were also determined. Findings showed that double injections of PGF_{2}\alpha at 10 or 14 day intervals did not significantly affect either the concentrations of plasma progesterone or the rates of oestrus and lambing. Plasma progesterone concentrations on the day of the second injection, 4 days post-injection and 16 days after insemination were 4.29 ± 1.96, 0.27 ± 0.19 and 7.39 ± 3.5 ng/ml in group I and 3.45 ± 1.45, 0.10 ± 0.02 and 9.21 ± 4.29 ng/ml in group II, respectively. The oestrus and lambing rates were 86.7% and 60.2% in group I, and 100% and 73.3% in group II, respectively. In conclusion, it appears that for oestrus synchronisation, shortening the interval of double injections of PGF_{2}\alpha by 4 days has little effect on plasma progesterone concentrations, oestrus or lambing rates in Tuj ewes during the breeding season.

First Page

207

Last Page

211

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