Searchable, peer-reviewed, open-access proceedings from bioscience and biomedical conferences

bp0006rdr20 | Embryo Technologies | REDR2006

State-of-the-art embryo technologies in cattle

Lonergan P

Over the past 30 years, basic and applied studies on classical and advanced embryo technologies have generated a vast literature on factors regulating oocyte and embryo development and quality. In addition, over this period, commercial bovine embryo transfer has become a large international business. It is well recognised that bovine embryos derived in vivo are of superior quality to those derived from in vitro maturation, fertilization and culture. Relatively little has chang...

bp0007rdr27 | Critical Issues Facing Global Ruminant Production | REDR2010

Using basic approaches to address applied problems in dairy reproduction

Lonergan P

Poor reproductive efficiency is a worldwide problem affecting the dairy industry. There is substantial evidence for an association between high milk production and lower conception rates observed in cows compared to heifers. However, whether the decline in fertility is due directly to the level of milk production or other factors associated with lactation is unclear. There are various checkpoints along the developmental axis which could, in part, contribute to reduced fertilit...

bp0007rdr30 | Managing Fertility in Domestic Ruminants | REDR2010

Causes and consequences of the variation in the number of ovarian follicles in cattle

Evans ACO , Mossa F , Fair T , Lonergan P , Butler ST , Zielak-Steciwko AE , Smith GW , Jimenez-Krassel F , Folger JK , Ireland JLH , Ireland JJ

Summary. In cattle we have noted that the antral follicle count (AFC, follicles ≥3 mm in diameter) varies greatly among animals (from 5 to 50), is repeatable within animals, and is highly correlated with the total number of healthy follicles in ovaries. Also, animals with low AFC have higher serum concentrations of FSH and LH, but lower concentrations of Anti-Mullerian Hormone, progesterone and androgens than animals with high AFC. We have investigated t...