Temporary suppression of ovarian follicular growth in sheep by use of implants for continuous release of deslorelin

• Grant number: 11/04365-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2012
• End date: November 30, 2013
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Sony Dimas Bicudo
• Grantee: Hyago Ramalho Leite
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The aim of this project is to study the temporary suppression of ovarian follicular growth in adult wooless ewes using continuous release implant of deslorelin (9.4 mg). Will comprise four groups depending on the permanence of the implant device and one control. The experiment will be divided into three steps: First, after an adjustment period the sheep of all groups and measure the dynamics of ovarian follicular growth, there will be synchronization of estrus by vaginal sponges and administration of eCG on protocol duration of 12 days. The second step, the implant maintenance period beginning on the sixth day after detection of estrus and duration will vary depending on the experimental group, being 10 days for DES10, 20 days for DES20, 30 days for DES30 and 40 days for DES40. The third step to begin in each group after removal of the implant and will last for at least 30 days after implant removal of the DES40 Group, or until at least 50% of the treated animals return to normal follicular growth. Animals in the control group will be monitored in an identical manner throughout the duration of this step. By hypothesis, deslorelin promote reversible suppression of ovarian follicular growth, depending on the time of the permanence of the implant. The results will be analyzed using descriptive statistics of those characteristics. Will be used chi-square test for comparisons of frequencies and the parameters that are experiencing conditions of normality in their distribution will be carried out analysis of variance and comparison test of averages (Tukey), using the statistical package Statistical Analysis System (SAS ) - version 5.0, with a significance level of 5%. With the confirmation of the expected results, strategies may be implemented in order to better control of ovarian overstimulation, apply to embryos transfers and ovum pick-up in ovine. (AU)