Evaluation of the estrus synchronization and reproductive performance of Farahani ewes during the breeding season following treatment with letrozole

Document Type : Research Paper

Authors

1 Assistant Professor, Department of Animal Science, Faculty of Agriculture and Environment, Arak University, Arak, Iran

2 Professor, Department of Animal Science, Faculty of Agriculture and Environment, Arak University, Arak, Iran

3 MSc Student of Animal Science, Faculty of Agriculture and Environment, Arak University, Arak, Iran

Abstract

    This study investigated the efficiency of substituting conventional gonadotropin-based technique with letrozole based regimen in reproductive parameters and hormonal changes in Farahani sheep during the breeding season. For this this purpose, 40 Farahani ewes (3-4 years, 44±2.3 kg BW, BCS 3.12±0.5) were treated with intravaginal CIDR for 14 days and then were divided into four groups: one group was considered as the control, the other groups received eCG (400 IU, intramuscularly), hCG (400 IU, intramuscularly) and letrozole (7.5 mg, oral), respectively. Blood samples were taken from three days before CIDR removal. The reproductive parameters were calculated after parturition. Fecundity and multiple lambing were numerically higher in the eCG group; however, there was no significant difference in reproductive performance between treatments. Estrogen concentrations showed an increasing trend in all treatments. Results of this study showed that letrozole was not a reliable substitute for eCG to increase the ovulation rate in sheep.

Keywords

References

Abecia, J. A., Forcada, F., & González-Bulnes, A. (2011). Pharmaceutical control of reproduction in sheep and goats. Veterinary Clinics: Food Animal Practice, 27(1), 67-79.
Al-Fadhli, R., Sylvestre, C., Buckett, W., Tan, S. L., & Tulandi, T. (2006). A randomized trial of superovulation with two different doses of letrozole. Fertility and sterility, 85(1), 161-164.
Ali, A. (2007). Effect of time of eCG administration on follicular response and reproductive performance of FGA-treated Ossimi ewes. Small Ruminant Research, 72(1), 33-37.
Benoit, A., Inskeep, E., & Dailey, R. (1992). Effect of a nonsteroidal aromatase inhibitor on in vitro and in vivo secretion of estradiol and on the estrous cycle in ewes. Domestic Animal Endocrinology, 9(4), 313-327.
Bhatnagar, A. S. (2007). The discovery and mechanism of action of letrozole. Breast cancer research and treatment, 105(1), 7-17.
Bister, J.-L., Noel, B., Perrad, B., Mandiki, S., Mbayahaga, J., & Paquay, R. (1999). Control of ovarian follicles activity in the ewe. Domestic Animal Endocrinology, 17(2-3), 315-328.
Cohen, M. H., Johnson, J. R., Li, N., Chen, G., & Pazdur, R. (2002). Approval summary: letrozole in the treatment of postmenopausal women with advanced breast cancer. Clinical Cancer Research, 8(3), 665-669.
Cortínez, A., De Carvalho, I., Vantman, D., Gabler, F., Iñiguez, G., & Vega, M. (2005). Hormonal profile and endometrial morphology in letrozole-controlled ovarian hyperstimulation in ovulatory infertile patients. Fertility and sterility, 83(1), 110-115.
Evans, A. (2003). Ovarian follicle growth and consequences for fertility in sheep. Animal reproduction science, 78(3-4), 289-306.
Gowri, V., Al-Amri, A., Almamari, T. M. A., Al Khaduri, M., & Jaju, S. (2022). The Success of Ovulation Induction with Letrozole and Gonadotropins in Obese and Nonobese Women: A Study from a Tertiary Center. International Journal of Reproductive Medicine, 2022.
Habibizad, J., Riasi, A., Kohram, H., & Rahmani, H. R. (2015). Effect of feeding greater amounts of dietary energy for a short-term with or without eCG injection on reproductive performance, serum metabolites and hormones in ewes. Animal reproduction science, 160, 82-89.
Hameed, N., Khan, M. I.-u.-R., Ahmad, W., Abbas, M., Murtaza, A., Shahzad, M., & Ahmad, N. (2020). Follicular dynamics, estrous response and pregnancy rate following GnRH and progesterone priming with or without eCG during non-breeding season in anestrous Beetal goats. Small Ruminant Research, 182, 73-77.
Kivrak, M. B., Corum, O., Alkan, H., Atik, O., Aydin, I., & Uney, K. (2021). The pharmacokinetics of letrozole and its effect on gonadotropins in anestrous ewes. Theriogenology, 176, 225-232.
Land, R. (1979). Improvement in gonadal function through modification of negative feed-back. Paper presented at the Annales de Biologie Animale Biochimie Biophysique.
MA, A. D. (2020). Effect of A Non-Steroidal Aromatase Inhibitor on Ovarian Function and Synchronicity of Estrus in Ewes at Subtropics. Journal of Applied Veterinary Sciences, 5(4), 1-9.
Mitwally, M. F., & Casper, R. F. (2002). Aromatase inhibition for ovarian stimulation: future avenues for infertility management. Current Opinion in Obstetrics and Gynecology, 14(3), 255-263.
Moakhar, H. K., Kohram, H., Shahneh, A. Z., & Saberifar, T. (2012). Ovarian response and pregnancy rate following different doses of eCG treatment in Chall ewes. Small Ruminant Research, 102(1), 63-67.
Nakafeero, A., Hassen, A., & Lehloenya, K. (2020). Investigation of ram effect and eCG usage in progesterone based oestrous synchronization protocols on fertility of ewes following fixed time artificial insemination. Small Ruminant Research, 183, 106034.
Ortiz-Carrera, L., Aceves-Ramos, A., Zarco, L., Valencia, J., & Romano, M. (2019). The effect of letrozole administration on the aggressive behavior and reproductive parameters of male goats (Capra hircus). Small Ruminant Research, 174, 69-76.
Quintero-Elisea, J. A., Macías-Cruz, U., Álvarez-Valenzuela, F. D., Correa-Calderón, A., González-Reyna, A., Lucero-Magaña, F. A., . . . Avendaño-Reyes, L. (2011). The effects of time and dose of pregnant mare serum gonadotropin (PMSG) on reproductive efficiency in hair sheep ewes. Tropical Animal Health and Production, 43(8), 1567-1573.
Rahminiwati, M., Boediono, A., & Manalu, W. (2017). Optimum dose and time of pregnant mare serum gonadotropin injections in Kacang goats to increase endogenous secretion of estrogen and progesterone without superovulation response. Small Ruminant Research, 149, 147-153.
Requena, A., Herrero, J., Landeras, J., Navarro, E., Neyro, J. L., Salvador, C., . . . Farré, M. (2008). Use of letrozole in assisted reproduction: a systematic review and meta-analysis. Human reproduction update, 14(6), 571-582.
Scaramuzzi, R., Baird, D., Campbell, B., Driancourt, M.-A., Dupont, J., Fortune, J., . . . McNeilly, A. (2011). Regulation of folliculogenesis and the determination of ovulation rate in ruminants. Reproduction, Fertility and Development, 23(3), 444-467.
Shilo, M., Mayo, A., & Alon, U. (2022). A Mechanism for Ovulation Number Control. Frontiers in Endocrinology, 13.
Sudhakar, B., Bhavya, Y., & Harika, J. (2022). Aromatase inhibitors: Their application in commercial broiler chick production.
Titi, H., Kridli, R., & Alnimer, M. (2010). Estrus synchronization in sheep and goats using combinations of GnRH, progestagen and prostaglandin F2α. Reproduction in domestic animals, 45(4), 594-599.
Yapura, M., Zwiefelhofer, E., Pierson, R., & Adams, G. (2018). Aromatase inhibitors: A new approach for controlling ovarian function in cattle. Theriogenology, 112, 18-25.
Yapura, M. J., Mapletoft, R. J., Singh, J., Pierson, R., Naile, J., Giesy, J. P., . . . Adams, G. P. (2012). Effects of a non-steroidal aromatase inhibitor on ovarian function in cattle. Reproduction, Fertility and Development, 24(4), 631-640.

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