Recovery rates and embryo quality following dominant follicle ablation in superovulated cattle

To determine the association between dominant follicle ablation and the outcome of a superovulatory regimen, two data sets were constructed from records of 171 recoveries from non-ablated cows and 1214 recoveries from cows that underwent follicular ablation prior to FSH treatment. Data set 1 included all cows with 2 or more records (n = 1385). Data set 2 included paired data for 87 cows which had at least 2 records of both ablated and non-ablated superovulatory attempts. Dominant follicle ablation was performed by use of transvaginal, ultrasound guided aspiration 48 hr prior to the start of FSH. The same FSH protocols were used for both ablated and nonablated cows. For all cows (data set 1), more total ova/embryos were recovered from the ablation group (12.1±0.3 vs 10.5±0.8; P=0.06). This difference could be accounted for by greater numbers of non-transferable embryos in the ablation group (6.5±0.2 vs 5.3±0.6; P>0.01). For the paired data (data set 2), greater numbers of total ova/embryos recovered from the ablation group (12.8±1.0 vs 9.7±0.7; P=0.01) could also be accounted for by higher numbers of nontransferable embryos in this group (7.8±0.8 vs 4.5±0.4; P>0.01). There were no differences between groups for high quality embryos, percent cows producing no ova/embryos or percent cows producing no transferable embryos. These data support the premise that synchronization of follicular waves following dominant follicle ablation increases total ova/embryo output. However, the additional embryos were primarily nontranferable thereby negating potential economic gains.