1. Aboagye, G.S. 2002. Phenotypic and genetic parameters in cattle populations in Ghana. A review paper presented to International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia. Accessed 7th September, 2013.
2. Barth AD. 1993. Factors affecting fertility with artificial insemination. Veterinary Clinics of North America: Food Animal Practice 9: 275–289
3. Debir L. B., Asrat T., Azage T. 2016. Evaluating the Efficiency of Artificial Insemination Following Estrus Synchronization of Dairy Cattle in Southern Region, Ethiopia: The Case of Dale District. Journal of Natural Sciences Research Vol. 6, No. 5, 2016
4. Diskin, M.G., Mackey D.R., Roche J.F., Sreenan J.M., 2003. Effects of nutrition and metabolic status on circulating hormones and ovarian follicle development in cattle. Animal Reproduction Science 78 (2003) 345–370.
5. Fekadu, A., Kassa, T. & Belehu, K. 2011. Study on reproductive performance of Holstein–Friesian dairy cows at Alage Dairy Farm, Rift Valley of Ethiopia. Trop Anim Health Prod (2011) 43: 581.