engleski

Influence of leptin and progesterone concentrations on embrionic survival rate during early pregnancy in the dairy cow

Abstract: Early pregnancy is critical period for embrionic survival and poor progesterone secretion following mating or increased metabolisation of progesterone in liver of high producing cow, is an important cause of early embryo mortality. In human, mice, ewes and many other species it is very well known connection between level of LH, progesterone, oestrogene and leptin with early embryo development and embryonic survival in the uterus.The aim of the present study was to determine whether the link exists between circulationg leptin concentrations and progesterone secretion at this critical time in cows. We preformed our study on 59 symmental cows who had no history of reproductive disturbancies, failures to conceive or difficult parturations. In our study we divided animals in 3 groups: pregnant, inseminated but nonpregnant and not inseminated cows. We collected blood every 72 hours during four weeks after oestrus from all cows (38 pregnant cows, 14 inseminated but nonpregnant and 7 noninseminated cows). We controled all the cows using ultrasound every week.. Progesterone concentration was lower in cows failing to conceive than in those becoming pregnant and increased significantly with increasing plasma leptin concentrations.There was no change in plasma leptin concentrations throw the sampling period in any group. Furthermore, plasma leptin concentrations were not different between pregnant, inseminated but nonpregnant and not inseminated cows. There was no correlation between plasma leptin and plasma progesterone. The results demonstrate that while a relationship may exist between leptin and progesterone in lactating cows, in the absence of the high metabolic load of milk yeald there appears to be no relationship betweeen leptin and either plasma progesterone or early embryo development.

leptin; progesterone; cow

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