Advances in our understanding of the estrous cycle and applications for improving targeted reproductive management in livestock.

The scientific discipline of endocrinology has been invaluable to our understanding of the estrous cycle. In the second half of the twentieth century the development of immunoassay technologies provided a rapid and sensitive method to quantify circulating concentrations of reproductive hormones and relate them to stage of the estrous cycle and physiological status of the animal. Ovarian ultrasonography provided the ability to track the growth and regression of ovarian structures within the same animal across the estrous cycle in real time and, in combination with hormonal profiling, accurately identify mechanisms regulating the estrous cycle and early pregnancy.

International Symposium on Ruminant Physiology: Paternal Nutrient Supply: Impacts on Physiological and Whole Animal Outcomes in Offspring.

Recent evidence suggests that environmental factors experienced by sires can be transmitted through the ejaculate (seminal plasma + sperm) into the female reproductive tract, influencing fertilization, embryo development, and postnatal offspring outcomes. This concept is termed paternal programming. In rodents, sire nutrition was shown to directly alter offspring outcomes through sperm epigenetic signatures, DNA damage/oxidative stress, cytokine profiles, and/or the seminal microbiome.

Transcriptomic analysis of luteal tissue supports the earlier onset of luteolysis in heifers with diminished ovarian reserve.

Context Antral follicle count (AFC) is reflective of ovarian reserve and linked to reproductive performance in mammalian females. We previously demonstrated earlier upregulation of endometrial oxytocin receptor transcription in heifers with low AFC, indicating an earlier onset of luteolysis. Aims We aimed to support the earlier onset of luteolysis in non-pregnant heifers with a low number of antral ovarian follicles (Open Low AFC) and hypothesized a reduced abundance of luteinizing hormone/choriogonadotropin receptor (LH/CG-R ) and increased abundance of thrombospondin-1 (THBS1 ) in luteal tissue of those heifers.

Fertility and early embryonic development in a CD46-edited Gir heifer with reduced susceptibility to BVDV.

Bovine viral diarrhea virus (BVDV) infection during pregnancy is a significant contributor to reproductive failures in cattle. The bovine receptor for BVDV (CD46) was previously edited with a six amino acid substitution (G82QVLAL to A82LPTFS) and shown to have significantly reduced BVDV susceptibility in a Gir heifer calf. Since a role for CD46 has been proposed in mammalian fertilization, our objective was to assess the edited heifer's fertilization rates, early embryonic development, and germline transmission conformation of the edit.

Delayed endometrial preparation for the induction of luteolysis as a potential factor for improved reproductive performance in Angus beef heifers with high antral follicle counts†.

Antral follicle count (AFC) and anti-Müllerian hormone (AMH) concentrations are reflective for ovarian reserve and have been associated with improved reproductive performance in cattle. Key events for regulation of uterine receptivity are orchestrated by progesterone. As progesterone concentrations are greater in animals with high than low AFC, we tested the hypothesis, if the resulting improved uterine environment will lead to improved conceptus elongation and endometrial response to interferon tau.