South African Journal of Animal Science
On-line version ISSN 2221-4062
RUST, J.M. et al. The effect of season on aspects of in vitro embryo production in sub-fertile beef cows. S. Afr. j. anim. sci. [online]. 2009, vol.39, n.5, pp. 275-279. ISSN 2221-4062.
This study was conducted to investigate the possible effect of season on in vitro embryo production (IVEP) in sub-fertile beef cows. Forty beef (40) cows of different breeds and parities were used in a trial conducted as part of a commercial embryo production programme. Animals were subjected to a once a week ultrasound guided oocyte recovery procedure (OPU) and all oocytes were entered in a commercial IVEP programme. A significant difference in follicular populations could be established for different months of the year. As for recovery rate, oocyte quality and embryo production, no significant differences could be established. However, the embryo production per OPU session per cow showed a definite seasonal pattern with low production during hotter months, a steady increase during the colder months and a peak in spring. This information should be helpful in the future planning of IVEP programmes for fertility-impaired cows.
Keywords : In vitro embryo production; OPU; season; fertility; assisted reproduction.