The effect of oestrus synchronization in two different periods on the reproductive performances of sheep under extensive production system

The aim of this study was to determine the effect of oestrus synchronization in two different periods on the reproductive performances of sheep under extensive production system. In this study, the estrus cycle of the ewes was synchronized in two different periods (before and during the mating season). This research was conducted on approximately 125 Kıvırcık sheep in breeders? farms and 8 Chios rams in Adnan Menderes University-Group Sheep Breeding Program (ADÜ-GKYP) flock for three years. The oestrus cycles of the ewes were synchronized with intravaginal progestagen sponges impregnated with 30 mg cronolone. After 14 days sponges were removed and the females received an intramuscular injection 500 IU (PMSG) and five or six ewes were mated with Chios rams. Before the introduction of rams, the ewes were weighed and body condition score (BCS) were determined only two years. This research was continued three years and detailed flocks recording were managed. Before and during the mating season the effect of hormonal synchronization on lamb production and the reproductive performances of sheep were determined and analyzed.A week before the introduction of rams, average body condition score (BCS) and live weight of Kivircik ewes were 49.63 kg and 2.25, respectively under extensive production system. The effects of years, periods and farms were significant on live weight and BCS. Pregnancy rate (%), lambing rate (%), fecundity and fertility for 365 Kıvırcık sheep were % 58.7, % 54.9, % 0.86 and % 2.73 respectively. The effect of farms were significant (P<0.01). The least-squares mean of ewe body weight at parturition was 43.48 kg, mean birth weight of lambs (Kıvırcık x Sakız F1) was 3.18 kg. Lambing season, birth type and sex of lambs for birth weight were significantly different (P < 0.01).The least-squares means of total productivity, lactation productivity, number of the marketing lambs and lambs marketing weight per lambed ewe were 12.44, 9.92, 1.07 and 30.51 kg respectively. In this research, average marketing weight and daily live weight of 245 lambs (Kivircik x Sakiz (F1) per mated ewe were 29.10 kg, 167.48 g, average number of marketing lambs and live weights of lambs (F1) were 0.60 and 17.45 kg respectively. Survival rate of lambs until 100 days of age and time of marketing were % 66.81 and % 63.57 respectively. The effect of years were significant (p<0.01).Key words: Kivircik, synchronization, lamb productivity, total fertility