The influence of exogenous progesterone supplementation in pregnant anovulatory embryo recipients on serum progesterone profile for different periods

• Grant number: 10/08279-6
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2010
• End date: July 31, 2012
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Cezinande de Meira
• Grantee: Cezinande de Meira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Recently, the use of exogenous progesterone in anovulatory embryo recipients with intention of maintaining pregnancy is commom on commercial embryo transfer programs. Progesterone is usually administered until 100-120 days of gestation, to ensure adequate concentrations of this hormone until complete fetal-placental maturation and development, as progestagens secretory unit. Thus, recent protocols present high costs and long duration, in addition to excessive animal management. Considering that supplementary corpora lutea development occurs from days 36 to 40 of gestation and that they are responsible for progesterone production until fetal-placental production of this hormone takes on, is presumable that progesterone injections are not necessary after formation of supplementary corpora lutea. The present work has as objective evaluate the effect of interruption of exogenous progesterone administration in anovulatory embryo recipients after supplementary corpora lutea formation on serum progesterone profile and maintenance of pregnancy. Twenty four mares distributed in three different groups, for 120 days, will be evaluated through ultrasound exams and serum progesterone quantification. The findings will open pathways for other researches, aiming the development of lower costs and short duration progesterone protocols, what will be valuable to veterinarians and producers. (AU)