Follicle-stimulating hormone to substitute equine chorionic gonadotropin in the synchronization of ovulation in Santa Inês ewes

Abstract

The substitution of equine chorionic gonadotropin (eCG) by follicle-stimulating hormone (FSH) in protocols for synchronization of ovulation in Santa Inês ewes was assessed. Ten females were submitted to the insertion of intravaginal sponges containing 60 mg medroxyprogesterone acetate for 10 days; after this period sponges were withdrawn and the animals were randomly divided into two groups. Group 1 (n = 5): intramuscular injection of 0.5 mL d-cloprostenol and 300 UI eCG; Group 2 (n = 5): intramuscular injection of 0.5 mL d-cloprostenol and 20 mg FSH. Interval between sponge withdrawal and estrus beginning was 27.7 h and 35.9 h for eCG and FSH, respectively. Interval between sponge withdrawal and the end of estrus was 55.8 h for eCG treatment and 55.6 h for FSH treatment. Estrus length was 29.3 h and 19.6 h, for eCG and FSH treatments, respectively. The biggest follicle and the second in size measured 0.74 cm and 0.54 cm for eCG treatment, whereas for the FSH treatment they measured 0.73 and 0.50 cm. The interval between the beginning of estrus and ovulation was similar within all groups: 21.0 h for eCG treated ewes and 25.2 h for the ones treated with FSH. Ewes treated with eCG presented an interval of 47.5 h between sponge withdrawal and ovulation, while the ones treated with FSH presented a 61.1 h interval. Ovulation occurred 8.3 h before the end of estrus in the eCG group. On the other hand, ewes treated with FSH ovulated 5.5 h after the end of estrus. Estrus and ovulation were efficiently synchronized in Santa Inês ewes by using long-term progestogen protocol associated to the administration of 20 mg FSH, along with Prostaglandin F2α (PGF2α) at the moment of sponge withdrawal, thus substituting the use of eCG

Polish Journal of Veterinary Sciences

“…Additionally, FSH administration may not have been sufficiently effective on ovulation of the graafian follicles on the ovary and only may have resulted in fewer CL due to an insufficient or delayed LH surge. These observations are consistent with the findings of previous studies (Driancourt and Fry 1992, Moakhar et al 2010, Neto et al 2012, who reported that eCG treatment increased the number of ovulations or CL on ovaries in sheep.…”

“…Additionally, Moakhar et al (2010) found that eCG treatment after CIDR application increased the number of large follicles on the ovaries on the basis of ultrasound scanning. However, ultrasound follicular dynamics assessments of Neto et al ( 2012) showed that eCG and FSH treatments had similar effect on the largest and second follicle size during the early follicular development phase in Santa Inês breed sheep. These differences may be explained by the dose of hormones used or genetic differences between sheep breeds.…”

“…In particular, such treatments have been commonly used to induce an out-of-breeding season for lambing programs aimed at meeting consumer demand for lamb meat (Kohno et al 2005, Ozyurtlu et al 2008, Santos et al 2011). In the commercial protocols eCG and FSH are the most frequently used hormones due to their effects on ovarian activity (Boscos et al 2002, Titi et al 2010, Neto et al 2012. The main mechanisms of eCG and FSH hormones are explained on the basis of FSH receptors present in the small and medium sized follicles and their involvement in the stimulation of follicle development (Cahoreau et al 2015).…”

Horse Welfare During Equine Chorionic Gonadotropin (eCG) Production

“…However, these methods do not optimize reproductive performance of livestock to the same extent as eCG, making them unlikely to be implemented in modern intensive farming systems. Attempts have been made to use other hormone s alone or in combination to replace eCG use, but these studies have not resulted in an efficacious product [15]. Recent discovery of kisspeptin, a neuropeptide critical for central control of reproduction, has suggested another means of controlling estrus and ovulation (reviewed by [16]).…”