Juliana Nascimento Duarte Rodrigues , José Domingos Guimarães , Paulo Sergio Cerqueira Rangel , Maria Emilia Franco Oliveira , Felipe Zandonadi Brandão , Pawel Mieczyslaw Bartlewski , Jeferson Ferreira Fonseca
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引用次数: 0
Abstract
The objective was to evaluate the effects of intramuscular (i.m.) human chorionic gonadotropin (hCG) administered on day 5 (D5) or day 7 (D7) after estrus (D0) on luteal structures (number, area, vascularization, and progesterone secretion) and pregnancy rates in estrus-induced dairy goats during the non-breeding season. Thirty-four Alpine goats received intravaginal sponges containing medroxyprogesterone acetate for 6 days and a single i.m. injection of 200 international units (IU) of equine chorionic gonadotropin (eCG) plus 37.5 micrograms (µg) of d-cloprostenol 24 hours before sponge removal. All exhibited estrus and were mated by fertile bucks. Goats were randomly assigned to hCG-5 (300 IU on D5; n = 12), hCG-7 (300 IU on D7; n = 11), or controls (n = 11). Transrectal ovarian ultrasonography and blood sampling were performed on D5, D7, D10, D13, D17, and D21, with pregnancy diagnosis on D60. hCG treatment did not affect pregnancy rates. Accessory corpora lutea (aCL) appeared in 66.6 % (hCG-5) and 90.9 % (hCG-7) (P > 0.05). Total luteal area in hCG-7 was greater (P < 0.05) than in controls from D10 to D21. The mean original corpora lutea (oCL) area in hCG-7 was largest (P < 0.05) on D10. High-velocity Doppler area (HVDA) of aCL was greater (P < 0.05) in hCG-5 compared with hCG-7 on D13. Plasma progesterone (P4) concentrations were higher (P < 0.05) in hCG-7 than in controls from D10 to D21. Although hCG administered on D5 or D7 transiently enhanced luteal function and vascularization, it did not improve pregnancy outcomes in seasonally anovular dairy goats.
期刊介绍:
Animal Reproduction Science publishes results from studies relating to reproduction and fertility in animals. This includes both fundamental research and applied studies, including management practices that increase our understanding of the biology and manipulation of reproduction. Manuscripts should go into depth in the mechanisms involved in the research reported, rather than a give a mere description of findings. The focus is on animals that are useful to humans including food- and fibre-producing; companion/recreational; captive; and endangered species including zoo animals, but excluding laboratory animals unless the results of the study provide new information that impacts the basic understanding of the biology or manipulation of reproduction.
The journal''s scope includes the study of reproductive physiology and endocrinology, reproductive cycles, natural and artificial control of reproduction, preservation and use of gametes and embryos, pregnancy and parturition, infertility and sterility, diagnostic and therapeutic techniques.
The Editorial Board of Animal Reproduction Science has decided not to publish papers in which there is an exclusive examination of the in vitro development of oocytes and embryos; however, there will be consideration of papers that include in vitro studies where the source of the oocytes and/or development of the embryos beyond the blastocyst stage is part of the experimental design.