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Pregnancies and calves derived from pre-puberal calf oocytes
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Theriogenology PREGNANCIES AND CALVES DERIVED FROM PRE-PUBERAL CALF OOCYTES X. Yang, G.A. Presicce, F. Du and S. Jiang
Department of Animal Science U-40, University of Connecticut, Storrs, CT 06269 USA Production of offspring from pre-puberal calves is of great interest to both the scientific and the commercial communities. In the last two years, attempts were made to produce calves from four genetically valuable pre-puberal heifers from Genex Inc. When the animals were 5, 7, 9 and 11 months of age, they were super stimulated by combinations of eCG/FSH treatments followed by ultrasound-guided transvaginal oocyte retrievals (TVOR). TVOR oocytes were matured for 22 h in TCM-199 medium plus 7.5% fetal calf serum (FCS) and hormones. Fertilization was conducted in BO medium for 6 h and embryos were cultured on cumulus-cell monolayers in TCM-199 plus 7.5% FCS for 6. The in vitro produced morula and blastocyst stage embryos were then transferred to synchronized recipient heifers at Day 6 of culture following IVF. The number of transferrable embryos produced from the four heifers and the calves resulting from these embryos are summarized in Table 1. Nine similarly produced IVF embryos derived from slaughterhouse oocytes resulted in 6 calves following embryo transfer. Table 1. Production of embryos and calves from the Genex pre-puberal heifers Heifer 5 month ID Embryos Calves
Gen Ashley Ann Anita TOTAL
-6 2 0 8
-1 0 0 1
7 month Embryos Calves
6 3 1 9 19
1 0 1 3 5
9 month Ilmonth Embryos Calves Embryos Calves
7 4 2 0 13
2 3 2 0 7
7 1 2 0 3
-_ 0 1 0 1
Although the numbers are small for statistical analysis, our results show that in vitro matured TVOR oocytes from gonadotropin stimulated pre-puberal heifers can be fertilized and that offsprings develop to term following embryo transfer. Oocytes collected from heifers at 7 months of age seemed more competent to develop into viable embryos and offspring than oocytes collected from heifers at 5 months of age while embryos from the heifers at 9 months of age produced the best pregnancy rate. The survival rate of embryos derived from the g-month-old calves (54%, n=13) was similar to that of embryos derived from slaughtered adult animals (67%, n=9). In conclusion, some oocytes from gonadotropin-treated pre-puberal calves are fully competent to develop to viable calves. More research is needed to improve the developmental competence of the pre-puberal calf oocytes particularly for calves at 5 and 7 months of age. This research is supported by Genex.
Theriogenology PREGNANCIES AND CALVES DERIVED FROM PRE-PUBERAL CALF OOCYTES X. Yang, G.A. Presicce, F. Du and S. Jiang
Department of Animal Science U-40, University of Connecticut, Storrs, CT 06269 USA Production of offspring from pre-puberal calves is of great interest to both the scientific and the commercial communities. In the last two years, attempts were made to produce calves from four genetically valuable pre-puberal heifers from Genex Inc. When the animals were 5, 7, 9 and 11 months of age, they were super stimulated by combinations of eCG/FSH treatments followed by ultrasound-guided transvaginal oocyte retrievals (TVOR). TVOR oocytes were matured for 22 h in TCM-199 medium plus 7.5% fetal calf serum (FCS) and hormones. Fertilization was conducted in BO medium for 6 h and embryos were cultured on cumulus-cell monolayers in TCM-199 plus 7.5% FCS for 6. The in vitro produced morula and blastocyst stage embryos were then transferred to synchronized recipient heifers at Day 6 of culture following IVF. The number of transferrable embryos produced from the four heifers and the calves resulting from these embryos are summarized in Table 1. Nine similarly produced IVF embryos derived from slaughterhouse oocytes resulted in 6 calves following embryo transfer. Table 1. Production of embryos and calves from the Genex pre-puberal heifers Heifer 5 month ID Embryos Calves
Gen Ashley Ann Anita TOTAL
-6 2 0 8
-1 0 0 1
7 month Embryos Calves
6 3 1 9 19
1 0 1 3 5
9 month Ilmonth Embryos Calves Embryos Calves
7 4 2 0 13
2 3 2 0 7
7 1 2 0 3
-_ 0 1 0 1
Although the numbers are small for statistical analysis, our results show that in vitro matured TVOR oocytes from gonadotropin stimulated pre-puberal heifers can be fertilized and that offsprings develop to term following embryo transfer. Oocytes collected from heifers at 7 months of age seemed more competent to develop into viable embryos and offspring than oocytes collected from heifers at 5 months of age while embryos from the heifers at 9 months of age produced the best pregnancy rate. The survival rate of embryos derived from the g-month-old calves (54%, n=13) was similar to that of embryos derived from slaughtered adult animals (67%, n=9). In conclusion, some oocytes from gonadotropin-treated pre-puberal calves are fully competent to develop to viable calves. More research is needed to improve the developmental competence of the pre-puberal calf oocytes particularly for calves at 5 and 7 months of age. This research is supported by Genex.