Study the ovarian function in Awassi ewes

An experiment was carried out on local Awassi ewes to study the reproductive performance, progesteron concentrations, accuracy of pregnacy diagnosis and other reproduction related criteria of Awassi ewes using radioimunoassay (RIA). A total of 18 nulliparous Awassi ewes, aged about 1 year and weighing on average 36.9 Kg was used. Live-weight changes were recorded weekly. Blood samples (5 ml) were collected from the jugular vein for about 1 year at 10.00h. Sera were prepared and stored at - 20 deg until assyed. The FAO/IAEA progesterone RIA kits were used. Two ewes aborted after about three-and-a-half months of pregnancy due to mechanical reasons. The remaining ewes (16) lambed between 30th November 1994 and 22nd February 1995. Sex ratio was 1:1 (8 males: 8 females). Average birth weights for both sexes was 5210 ± 525 g. Average birth-weight was higher in males than females. Average male birth-weights was 5338 ± 515 g, (4600 - 6000 g) whereas was 5083 ± 538 g, (4180 - 5700 g) for female lambs. Average basal pre-mating progesterone concentration was 0.60 ± 0.42 n mol/l (0-1.7 n mol/l). Average maximum progesterone concentration during the luteal phase in non-pregnant ewes was 11.1 ± 3.1 n mol/l (5.8 -18.00 n mol/l). Average maximum progesterone concentration during gestation was 58.4 ± 20.9 n mol/l (29.25 - 100.00 n mol/l). The accuracy of pregnancy diagnosis at around 21 days post mating using RIA was 100%. It is concluded that RIA could be used for progesterone determination in Awassi sheep successfully, and that more research work on other aspects of reproduction in Awassi sheep should be carried out. (Author). 29 refs., 47 tabs., 5 figs