Different synchronization applications on pregnancy rates in sheeps during the breeding and out of breeding season

The aim of this study was to investigate the efficacy of short term (7 days) and long term (14 days) use of progesterone-impregnated intravaginal sponge on some reproductive parameters of ewes during and outside of the breeding season. For this purpose, 80 Merino ewes aged 2-4 years with at least one previous birth in a private enterprise in Burdur province were selected and randomly divided into 4 equal groups. The groups were determined as BS7: short term in breeding season (7 days), BS14: long term in breeding season (14 days), OBS7: short term out of breeding season (7 days) and OBS14: long term out of breeding season (14 days). At the end of the application, the sponges were removed and PMSG at a dose of 600 IU was injected i.m. in all groups. Two teaser rams were used for oestrus monitoring 24 hours after injection. Ewes in which oestrus was detected were mated with 2-4 year old rams known to be fertile by hand mating method. Following the matings, pregnancy rates on the 35th day and postpartum fertility parameters (oestrus occurrence rate, mating rate, pregnancy rate on the 35th day, birth rate, number of offspring) were recorded. According that records, oestrus occurrence and mating rates were determined as 100% in all groups. Pregnancy rates were determined as BS7: 75% (15/20); BS14: 90% (18/20); OBS7: 80% (16/20); OBS14: 85% (17/20) and birth rates as BS7: 75% (15/20); BS14: 80% (16/20); OBS7: 70% (14/20); OBS14: 85% (17/20) and lamb yield was recorded as BS7: 1.20 (18/15); BS14: 1.38 (22/16); OBS7: 1.35 (19/14); OBS14: 1.23 (21/17). According to the results obtained, the highest pregnancy rate and litter yield were obtained in the Sİ14 group, but there was no statistical difference between the groups (p>0.05). When the birth rates were analysed, no statistical difference was found between the groups (p>0.05), although a numerically high rate was obtained in the BS14 application group. As a result, it was concluded that although long term sponge applications had numerical superiority on fertility, short term sponge applications could be used for oestrus synchronisation of ewes in the in-season or off-season period.