Effect of hCG administration in different days of the estrous cycle on serum progesterone concentration and uterine and ovarian blood flow in mares

Author(s)

Maria Augusta Alonso

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2013-04-18

Examining board members

Rubens Paes de Arruda; Marco Antonio Alvarenga; Eneiva Carla Carvalho Celeghini; Claudia Barbosa Fernandes; Luciano Andrade Silva

• Advisor: Rubens Paes de Arruda

Abstract

The use of drugs during diestrus in order to improve conception rates in inseminated and recipient mares has been the focus of several research groups. Studies using hCG found promising results regarding pregnancy rates and recipient uterine characteristics on the Day of the transfer. The objective of the study was to evaluate the effect of hCG administration in different moments of the oestrous cycle on reproductive tract characteristics, vascularization and serum progesterone concentration. Therefore, groups consisted of control, hCG to induce ovulation; hCG on day 0 and hCG on day 5 postovulation. The current study was performed as a preliminar study with 4 animals per group, one cycle each animal and a main study with 12 animals per group, each animal receiving all the treatments during consecutive cycles. The evaluations were performed daily from day 0 until day 15 postovulation. Characteristics examined were uterine tone, morphoecogenicity and vascularization; cervical tone; area, diamaterand vascularization of the corpus luteum, ovarian pedicle vascularization and RI; mesometrial vascularization and RI. Besides, blood samples were collected for serum progesterone concentration. No diferences were detected comparing treated and control groups. The characteristics only varied through the days, as described in the literature. Therefore, it can be concluded that hCG administered to induce ovulation, on the day of ovulation and on day 5 postovulation did not alter the characteristics evaluated in the current study. (AU)

• FAPESP's process: 10/10932-0 - Effects of hCG administration on different estrous cycle days on plasmatic progesterone concentration and uterine and ovarian blood flow in mares
• Grantee: Maria Augusta Alonso
• Support Opportunities: Scholarships in Brazil - Doctorate