Comparison of the developmental competence of in vitro-produced mouse embryos cultured under 5 versus 2% O with in vivo-derived blastocysts.

Purpose: The prevalence of infertility in Canada has substantially increased over 30 years, and plateaued success rates of culture systems warrant further optimization for transfer outcomes. In clinical programs, embryos commonly undergo extended culture under 5% O until the blastocyst stage. The aim of this study is to characterize the developmental competence and stress-related responses of embryos cultured under 5 versus 2% O in comparison to in vivo-derived blastocysts.

Optimized total RNA isolation from bovine sperm with enhanced sperm head lysis.

Increasing evidence of sperm RNA's role in fertilization and embryonic development has provided impetus for its isolation and thorough characterization. Sperm are considered tough-to-lyse cells due to the compact condensed DNA in sperm heads. Lack of consensus among bovine sperm RNA isolation protocols introduces experimental variability in transcriptome studies.

Angus bulls voluntarily access shade during hot weather, reducing scrotal subcutaneous temperatures and improving sperm quality.

The objective of this study was to determine the relationship of bull location (shade no shade), scrotal subcutaneous and ambient temperatures, and sperm quality. Six Angus bulls (4 to 5 y) were randomly allocated into 2 groups of 3 bulls each, housed in 2 outdoor pens, with 1 containing a shed (~3.5 × 6 m and 2.

Melatonin improves post-thaw sperm quality after mild testicular heat stress in rams.

The objective was to determine effects of slow-release melatonin on post-thaw sperm quality in rams exposed to mild testicular heat stress (HS; scrotal neck insulation). Twelve yearling Dorset rams were randomly and equally allocated to receive either 36 mg melatonin in 1 ml corn oil or 1 ml corn oil injected subcutaneously (SQ); 15 day later, all rams had HS for 96 h (start of HS = start of Week 0). Semen was collected before HS and once weekly from Weeks 1 to 7, extended in Steridyl CSS One Step, held at 5°C for ~3 h, loaded into 0.

Testis-Specific Isoform of Na-K ATPase and Regulation of Bull Fertility.

An advanced understanding of sperm function is relevant for evidence-based male fertility prediction and addressing male infertility. A standard breeding soundness evaluation (BSE) merely identifies gross abnormalities in bulls, whereas selection based on single nucleotide polymorphisms and genomic estimated breeding values overlooks sub-microscopic differences in sperm. Molecular tools are important for validating genomic selection and advancing knowledge on the regulation of male fertility at an interdisciplinary level.