This study was carried out to investigate effects of breed, mating season, age of ewe, birth type, sex of lamb and birth weight on gestation length in Hamdani, Red Karaman and Karakul ewes. In the study, data on 259 lambings of Hamdani, Red Karaman and Karakul sheep were analyzed.
Gestation length for Hamdani, Red Karaman and Karakul ewes were 149.77+0.18, 148.76±0.15 and 147.79±0.19 days, respectively. Gestation length was affected by breed (P<0.01). Gestation lengths of mated ewes in different seasons were similar (P>0.05). Gestation lengths of 2-yr-old ewes (148.76±0.17) and 4-yr-old ewes (148.78±0.12) were similar (P>0.05). Gestation length of ewes which gave birth to single lambs (149.36±0.11) were longer than those which gave birth to twin lambs (148.18±0.21) (P<0.01). Gestation length of ewes giving birth to male lamb (149.17±0.14) were longer than those giving birth to female lamb (148.37±0.13) (P<0.01). The ewes which gave birth to heavier lamb had a longer gestation length (P<0.01). This study showed that the gestation length was affected by breed, sex of lamb, birth type and birth weight of lamb, and was not affected by mating season and age of ewe.