Publications by authors named "Katherine S Hackbart"

Article Synopsis
  • The study involved 17 nonlactating Holstein cows to assess how increased levels of propylene glycol (PROP) and luteinizing hormone (LH) influence ovarian function and embryo quality during follicle development.
  • PROP administration raised glucose and insulin levels but did not significantly increase the number of large follicles that ovulated, though it did reduce the fertilization rate.
  • The results suggest that an acute rise in insulin before ovulation negatively affects the ovulation rate of large follicles, especially when paired with high LH levels, without impacting embryo quality.
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Our objective was to compare several experimental preparations of a single injection of long-acting recombinant bovine FSH (rbFSH; types A and B) to a porcine pituitary-derived FSH (Folltropin) to superovulate Holstein dairy heifers. Nonlactating, nonpregnant virgin Holstein heifers (n = 56) aged 12 to 15 months were randomly assigned to one of four superstimulatory treatments. Beginning at a random stage of the estrous cycle, all follicles greater than 5 mm were aspirated.

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Maternal nutrition exclusively during the periconceptional period can induce remarkable effects on both oocyte maturation and early embryo development, which in turn can have lifelong consequences. The objective of this study was to evaluate the effect of maternal methionine supplementation on the transcriptome of bovine preimplantation embryos. Holstein cows were randomly assigned to one of two treatments differing in level of dietary methionine (1.

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Polycystic ovarian syndrome (PCOS) is characterized by hyperandrogenemia, polycystic ovaries, and menstrual disturbance and a clear association with insulin resistance. This research evaluated whether induction of insulin resistance, using dexamethasone (DEX), in a monovular animal model, the cow, could produce an ovarian phenotype similar to PCOS. In all of these experiments, DEX induced insulin resistance in cows as shown by increased glucose, insulin, and HOMA-IR (homeostasis model assessment of insulin resistance).

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