Production of embryos from repeated superovulations of cows during one calving interval
2002
Zizlavsky, J. | Machal, L. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic)) | Riha, J. | Urban, F. | Stipkova, M.
We studied quantitative and qualitative characteristics of cattle embryos obtained from dairy cows after multiple superovulations during one calving interval. Three herds of Czech Pied cattle and two herds of Holstein cows were used in the experiment. High producing cows were selected as potential donors and temporarily excluded from natural reproduction. A controlled superovulation was performed in 82 cows in 2 to 4-month intervals. We obtained 1,645 transferable embryos from 292 repeated superovulations. A significant combined effect of the herd-year-season on the production of transferable embryos was observed. The effect of the number of lactation, number of superovulation and the effect of milk efficiency in the previous lactation expressed by the herd index were all statistically insignificant. The yield of transferable embryos from the first superovulation was largely affected by the individuality of the cow (0-27 embryos). The period between 56 to 115 days after calving is considered to be the most suitable for the first superovulation. The results of the first superovulation can be used to predict the success of the following superovulation, because a correlation (r = 0.71) was found between the n and the n+1 superovulation.
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