Study of follicular characteristics of young and old mares evaluated by ultrasound B-mode and color Doppler and the relationship with the ovulation-inducing agent and ovulation time

• Grant number: 10/07088-2
• Support Opportunities: Regular Research Grants
• Start date: September 01, 2010
• End date: August 31, 2012
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Marco Antonio Alvarenga
• Grantee: Marco Antonio Alvarenga
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Recent studies in mares indicated that the vascularization of the preovulatory follicle evaluated by color Doppler ultrasound and ovulation time have a high correlation, showing that four hours before the ovulation the follicular vascularization decrease significantly. In equine reproduction most of old mares are kept in reproduction centers. Those mares have low fertility rate, small LH concentration and consequently more follicular maturation and ovulation disorders. To have more fertility from low fertility semen, cooled or frozen, artificial insemination is necessary and need to be performed nearly of ovulation time, and for that is important techniques that can predict ovulation. The purpose of the present study is to study the follicular vascularization by Doppler ultrasound and other follicular features evaluated by modo-B ultrasound of 100 estrous cycles of old and young mares, when two ovulation-inducing agent are used (hCG or GnRH). The aim of the present study is verify if Doppler ultrasound can to determine more specifically the ovulation time, and to verify if the follicular response is different for the ovulation-inducing agents as among old and young mares. The LH rates also will be evaluated after the ovulation induce. (AU)