Comparative analysis of follicular morphology, growth and fetus dimensions of Awassi ewes after rFSH or eCG treatment

Abstract

The study was carried out on 16 pluriparous Awassi ewes to assess the potential for replacing recombinant follicle stimulating hormone (rFSH) for Equine chorionic gonadotropin (eCG) in estrus induction programs during the non-breeding season.

The ewes were divided randomly into two groups, 8 ewes of each. The estrus was induced in the first experimental group using the traditional vaginal sponge program based on progesterone and eCG injection at sponges removal, and in the second experimental group with the administration of rFSH at sponges withdrawal, and with Gonadotropin-releasing hormone (GnRH) after 52 hours for ovulation induction.

The ewes were artificially inseminated at the first estrus. The ovarian follicles were monitored by ultrasound with a rectal linear probe with a frequency of 7.5 MHz. Pregnancy was diagnosed ultrasonographicaly on days 35, 42, 44 and 56 after A.I. All data were analyzed statistically using the SAS® 9.2 software.

Non-Significant differences (P>0.05) were recorded in the mean  numbers of small and medium follicles in both the eCG and rFSH groups. No large follicles were recorded after 24 and 48 hours of treatment with both hormones, and the hormonal treatment did not significantly affect the rate of follicular growth, the CRL and width of fetuses in ewes.

As a result, rFSH can be substituted for stimulate follicular growth in Awassi ewes during the nonbreeding season.