Abstract
The aim of this study was to compare the efficacy of estrus induction and fertility by using
subcutaneous melatonin (MEL, T1) and short-term intravaginal medroxyprogesteronacetate plus
pregnant mare serum gonadotropin treatments (sMAP+eCG, T2) in ewes on seasonaly anestrus.
In this study, 105 mature clinically healthy Kivircik ewes in anestrus season and 4 rams were used.
After synchronization applications, ewes exhibiting estrus signs were hand-mated with rams
known to be fertile. Blood samples were collected at different times in order to determine progesterone
(P4) concentrations. Results showed that estrus manipulation protocols induced significant
improvement in pregnancy rate. All the fertility results obtained with the sMAP+eCG or
MEL groups were similar, in seasonal anestrus. The efficacy duration of P4 in the MEL group was
longer than that in short-term progestagen group. Plasma P4 concentrations was significantly
different between the first (I) and last (III) measurement days (p<0.01). Increase in P4 concentration
in T2 group was faster than that in T1 group, and blood P4 concentrations at higher levels
could successfully be achieved by using any of the protocols in this study during the seasonal
anestrus. In conclusion, according to the results obtained, the hormone application groups received
very high estrus response. In addition, the twin ratio was found to be higher in T1 group
compared to those determined in the other groups (T2 and Control group). Furthermore, plasma
P4 concentrations and high birth rates were obtained in ewes in T1 and T2 groups. These procedures
can be considered a good alternative to traditional procedures due to its flexibility under
field conditions.
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