Ultrasound Guided Transvaginal Follicular Aspiration And In Vitro Embryo Production In Cows
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Date
2004
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Publisher
Tamil Nadu Veterinary and Animal Sciences University
Abstract
Ultrasound guided transvaginal follicular aspiration (TVFA) and ovum pick up (OPU) to collect
oocytes from live cows for in vitro embryo production has opened up greater possibilities to exploit
productive and reproductive potential of the valuable donor.
Experiment I was designed to study the effect of once versus twice a week OPU on size
distribution of follicles, aspiration rate, oocyte recovery rate, oocyte quality and embryo development. The
results of the present study showed that a highly significant (P<0.01) difference in the distribution of
medium sized follicles existed between once (2.33 ± 0.37) and twice (5.48 ± 0.79) a week aspiration. The
total number of follicles aspirated and oocytes recovered were significantly higher in twice (4.13 ± 0.48
and 1.25 ± 0.30) than once (2.17 ± 0.32 and 2.24 ± 0.30) a week group. The quality of A, B and C grade
oocytes were significantly higher in twice than once a week aspiration group.
In the second experiment, between FSH treated and untreated groups, the distribution of small and
medium sized follicles (0.92 ± 0.22 vs 2.57 ± 0.68), number of follicles available for puncture (9.48 ± 0.92
vs 5.10 ± 0.67), number of follicles aspirated (7.28 ± 0.81 vs 2.24 ± 0.20) and mean number of oocytes
recovered (5.48 ± 0.79 vs 1.24 ± 0.18) were significantly higher in FSH treated than untreated group. The
quality of B and C grade oocytes obtained were significantly higher following FSH treatment. The mean
percentage of cleavage rate and embryos reaching 4 cell stage did not differ between groups but the further
development of 4 cell stage embryos to 8 to 16 cell and > 16 cell was observed only in the FSH treated
group. There was no statistical difference existed between oocytes supplemented with cysteamine and with
out cysteamine on maturation rate and embryo development rate. The in vitro development of embryos
through IVMFC were corresponding to the time of development and DAPI staining of embryos showed a
perfect nuclei: blastomere ratio.
Out of 128 in vivo day 7 embryos examined, the proportion of compact morula, early blastocyst,
blastocyst and expanded blastocyst were 52.34, 16.40, 28.12 and 3.12 per cent, respectively. The
percentage of grade 1, 2, 3 and 4 of compact morula were 32.83, 35.82, 30.00 and 1.49; for early blastocyst
were 61.90, 38.09, 0.00 and 0.00; for blastocyst were 55.55, 36.11, 8.33 and 0.00 and for expanded
blastocyst were 100.00, 0.00, 0.00 and 0.00 per cent, respectively.
Viability assessment of in vivo embryo showed that, the embryos classified as grade 1 (excellent),
2 (good) and 3 (fair) resulted in pregnancy rate of 21.42, 11.76 and 0 per cent, respectively.Morphologically graded fair quality embryos were found to be dead on FDA staining and DAPI staining
showed less number of blastomere nuclei (18 to 31).
Effect of OPU on donor cows showed that there was no pathological changes observed at the site
of epidural injection, fornix vagina and ovary.
In conclusion, the results of the present study showed that transvaginal follicular aspiration and
OPU was an effective technique for successful recovery of oocytes from living cows. Increasing the
frequency of aspiration to twice a week resulted in generation of higher percentage of good quality oocytes
than once a week group. Further, FSH pretreatment of donors prior to OPU greatly enhanced the overall
OPU efficiency and in vitro embryo production rate. Transfer of morphologically assessed in vivo embryos
resulted in acceptable pregnancy rate and assessment of viability using in vitro culture and staining
technique would further improve the pregnancy rate and the efficiency of embryo transfer technology.
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Keywords
Transvaginal follicular aspiration, OPU, cow, in vitro embryo production