Reproductive cycles in white Karaman ewes: comparison of ovarian hormone secretion and reproductive behavior in non-pregnant and pregnant ewes in semi-intensive conditions

The objective of this study was to characterize the reproductive cycle both endocrinologically and behaviorally in ewes. Blood samples were analyzed by EIA for progesterone (P 4 ), and RIA for estradiol in order to determine the breeding strategy of non-pregnant (n = 11) and pregnant (n = 9) White Karaman throughout the year in the Middle Anatolia (39.57 0 N, 32.53 0 W), Turkey. Estrous cycle lengths and estrous lengths were 18.36 ± 1.03 days and 35.16 ± 5.95 hours, respectively. The breeding season durations were 283 ± 63.36 days and 229.64 ± 63.74 days according to hormonal and behavioral data respectively (p £ 0.01). The highest and lowest data of estrous occurrence frequency was observed in October and June-July, respectively. P 4 levels ranged from 0.01 to 9.0 ng mL -1 throughout the year and from 0.01 to 0.16 ng mL -1 during anestrous. Mean plasma estradiol levels were 8.42 ± 2.51 pg mL -1 during the estrous cycle. Postpartum anestrous durations were 134.8 ± 18.5 and 120.78 ± 29.89 days (n = 9) according to behavioral observation and hormonal data, respectively. P 4 concentration for the months 1 – 5 of the gestation period ranged from 4.54 to 15.08 ng mL -1 . P 4 concentrations in 4 th and 5 th months of gestation were higher than the other months (p £ 0.01). White Karaman reproductive activity is characterized by an extended breeding season and their relatively insensitivity to photoperiod stimulation allows for efficient out of season lamb production.