Reduction of nutrients concentration in culture medium has no effect on bovine embryo production, pregnancy and birth rates.

To improve the quality of in vitro produced (IVP) embryos and reduce pregnancy losses, we proposed to reduce the components of the synthetic oviduct fluid (SOF) medium by 0% (SOF100), 50% (SOF50), and 75% (SOF25). First, embryos produced under these three treatments were evaluated for production, quality, lipid content, gene expression, and methylation patterns. The results indicated that all parameters analyzed were similar across all treatments (P > 0.

Use of color-Doppler ultrasonography for selection of recipients in timed-embryo transfer programs in beef cattle.

We aimed to study the association between CL characteristics assessed by color-Doppler ultrasonography (Doppler-US) at the time of embryo transfer (ET) and pregnancy rate (P/ET) in beef recipients. Estrous cycles of crossbred beef recipients were synchronized for timed-ET. On the day of ET (Day 7), CL area, proportion of luteal blood perfusion (BP), and the relationship between the largest dominant follicle (DF) and CL (ipsilateral or contralateral) were determined.