[Endocrine status and pregancy of multi-embryo none-calving young cows]
2006
Gavrichenko, N.I.,Armenian State Agrarian Univ., Yerevan (Armenia)
The character of changes in the endocrine status of multi-embryo none-calving young cows in the beginning of pregnancy in normal and pathological conditions has been examined. Crucial period is the 33rd day after insemination, when there happen considerable changes in concentration of kortizol, tireotropin, tireoid, gonadotroph and sex hormones in the cows. If the number of embryos, developing in the uterus until the 33rd day of pregnancy, exceeds the limit of the cow productivity, the cow organism begins to inhibit the reproduction function. Shifts in concentration of kortizol, tireotropin, tireoid hormones in this period testify that multi-embryo pregnancy is the strong stress for cows. In an organism specific adaptable processes are shown and the stereotypic complex of nonspecific protectively-adaptive reactions, characterised for a stage of alarm of the general adaptable syndrome, directed on increase of resistance of organism to higher loadings develops. To 33rd day the level of gonadotroph hormones at none-calving young cows with unsuccessful current of pregnant reduces and the content of sexual hormones, especially estrogen increases. It causes decrease in a parity of progesterone/estrogen that stimulates synthesis luteolitical factors by endometrij and increase in activity of miometrij. On 45-48th day at cows with unsuccessful current of pregnancy are observed endocrine shifts, characterized for normal birth: the level of progesterone significantly decreases, activity of forward share of a hypophysis increases, synthesis and secretion of sex hormones (especially estradiol) essentially amplifies and there is an abortion. It is necessary to note, that death of embryos occurs before abortion. In the present research at abortion on 48-5th day the lost embryos were at a stage of 33-35-day development. In previous investigations the majority of abortions took place on 45-70 day
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Эту запись предоставил National Academy of Sciences of Belarus