Browsing by Author "Vasquez Hidalgo, Manuel Alexander"

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    Effects of Nutrient Restriction, Realimentation, and Parity on Umbilical Hemodynamics in the Pregnant Ewe
    (North Dakota State University, 2016) Vasquez Hidalgo, Manuel Alexander
    Sheep are normally managed within grazing systems; forage availability and quality are dependent upon seasonal conditions such as drought and humidity. It is therefore important for producers to know when during gestation it is critical to supplement animals with additional feed. Previous research has shown that nutrient restriction during mid-gestation causes a decrease in umbilical blood flow with a possible consequent decrease in fetal body weight and size. Our findings indicate that a decrease in umbilical blood flow upon nutrient restriction during mid-gestation is not solely a consequence of the restriction itself or an additional effect of parity. Moreover, it appears very probable that such a decrease is also an effect of maternal age during pregnancy. In order to address this question further investigation is needed.
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    Effects of Nutrient Restriction, Realimentation, and Twinning on Plasma Volume, Umbilical Hemodynamics and Placental Characteristics in the Pregnant Adolescent Ewe
    (North Dakota State University, 2019) Vasquez Hidalgo, Manuel Alexander
    Reproductive physiology in production animals is a key economic component of longevity and profitability of animal farming. There are several components that can benefit or compromise adequate pregnancy periods. Sheep production is not only a very important economic activity for farmers around the United States, but sheep are also an important medical and surgical model to study human diseases. Our findings suggest that estradiol-17 beta could be involved in acute increased plasma volume early in gestation which can benefit overall gestation. We report that umbilical blood flow decreases upon nutrient restriction in adolescent ewes and does not recover upon realimentation. Finally, we suggest that a similar umbilical blood flow, placental development and plasma volume expansion in twins and singleton pregnancies could be enough to obtain similar birthweights in singletons and twins.