Alterations in embryo development in progestogen-supplemented cows administered prostaglandin F_(2alpha)

摘要

The obj ective was to examine effects of elevated prostaglandin F_(2alpha) (PGF) on embryo development in cows supplemented with exogenous progestogen. Cows were artificially inseminated at estrus (Day 0) and a synthetic progestogen supplemented in the feed from Days 3 to 8. Cows were allotted randomly to receive either 15 mg PGF (TRT) or saline (CON) at 06:00,14:00 and 22:00 h from Days 5 to 8. Blood samples were collected at 06:00 and 22:00 h from Days 5 to 8 for determination of progesterone and 13,14-dihydro-15-keto-PGF2alpha (PGFM). Single embryos were recovered on Day 8, assigned a quality score, and stage of development recorded. Progesterone was lower from Days 5 to 8 in TRT versus CON cows (P = 0.0001). Concentrations of PGFM from Days 5 to 8 were elevated in TRT compared to CON cows (P = 0.0001). Embryo quality was reduced in TRT cows compared to CON cows (P = 0.059). Percentage of embryos considered transferable was decreased by administration of PGF (P = 0.003). Sixty-four percent of TRT embryos were retarded in development at Day 8, whereas 80% of CON embryos had developed to expanded blastocysts (P = 0.003). In conclusion, treatment of progestogen-supplemented cows with PGF reduced quality and retarded development of embryos. Decreased fertility in conditions causing elevated concentrations of PGF may result from altered embryo development and quality.