Ovarian status in fat-tailed Syrian Awassi ewes during different reproductive stages and hormonal treatments monitored by laparoscopy and progesterone concentrations

Abstract

A study was conducted on seven Syrian Awassi ewes subjected to three treatments: (1) outside the breeding season without any other treatment applied (O + UT group), (2) outside the breeding season but treated with intravaginal sponges (flugestone acetate: [FGA]) only (O + FGA) and (3) inside the breeding season but treated with both FGA and equine chorionic gonadotropin (eCG) (I + FGA + eCG group). Parameters of the ovarian activity in each ovary were monitored by a laparoscope. The progesterone concentrations in blood serum were determined by a radioimmunoassay technique. Diameters of the ovaries and numbers of ovarian follicles were significantly higher (p<0.05) in the ewes treated with FGA. The mean diameters of the ovaries were 1.24, 1.46 and 1.55 cm for ewes in the O + UT, O + FGA and I + FGA + eCG groups, respectively, with no significant differences (p>0.05) in the diameters between the right and left ovaries within the same group. The mean numbers of the <3 mm and 3–5 mm follicles were 5.8 and 0.37, 10.6 and 1.4 and 9.9 and 1.9 follicles for ewes in the O + UT, O + FGA and I + FGA + eCG groups, respectively. Unlike the other two groups, there were no follicles larger than 4 mm found in the ovaries of ewes in the O + UT group. However, follicles larger than 5 mm were found only in some ovaries of the I + FGA + eCG group. No corpora lutea (CL) were found in the ovaries of ewes in the O + UT group. Functional CL were formed in ovaries of ewes in the O + FGA and I + FGA + eCG groups. The latter treatment produced significantly higher numbers, larger sizes and longer lifespans of CL (numbers: 1.6 vs 2.4; diameters: 8.1 vs 8.8 mm and lifespans: 10.7 vs 13.0 d, respectively). Likewise, the mean progesterone concentration during the luteal phase was significantly higher (p<0.05) in the latter than in the former group (20.79 vs 10.23 nmoL l⁻¹, respectively). There were no adhesion formations in the studied organs, or any mortality case among ewes following repeated laparoscopic observations. Therefore, laparoscopy could be safely and repeatedly applied on the same ewe without health problems.

Keywords:

• Ovary
• corpus luteum
• laparoscope
• progesterone
• Syrian Awassi ewe

Acknowledgements

The authors would like to thank the Director General and the Head of the Department of Agriculture of the Atomic Energy Commission of Syria for their support.