Relationship between Transferable Embryos and Major Metabolite Concentrations in Holstein Donor Cows

This research was investigated the relationship, in high-producing Holstein donor cows, between the number of the transferable embryos and the blood serum concentrations of Blood Urea Nitrogen (BUN), glucose and cholesterol, which affect the nutritional state of cows. CIDRs were inserted into the vaginas of twenty two heads of Holstein cows, regardless of estrous cycle. Superovulation was induced using folliclar stimulating hormone (FSH). For artificial insemination, donor cows were injected with $PGF_{2{\alpha}}$ and estrus was checked about 48 hours after the injection. Then they were treated with 4 straws of semen 3 times, with 12-hour intervals. Embryos were collected by a non-surgical method 7 days after the first artificial insemination. The total numbers of ova collected from 3 experimental groups whose blood BUN concentrations were <10 mg/dl, 11~18 mg/dl and ${\geq}19$ mg/dl were 8.9, 12.5 and 19.0, respectively; whereas the numbers of transferable embryos were 5.8 + 1.9, 7.9 + 2.8 and 5.2 + 1.4, respectively. When glucose concentration was <60 mg/dl, the total number of collected ova was 9.9, which was smaller than when the concentration was 60~70 mg/dl or ${\geq}70$ mg/dl. When glucose concentration was 60~70 mg/dl, the number of transferable embryos was 7.1 + 2.4, which was slightly larger than the numbers 6.4 + 2.1 and 6.1 + 1.7 that were obtained when the concentrations were <60 mg/dl and ${\geq}70$ mg/dl, respectively ; however, the differences were not significant (p>0.05). When cholesterol concentrations were <150 mg/dl, 150~200 mg/dl and ${\geq}200$ mg/dl, the total numbers of collected ova were 11.2, 11.3 and 8.6, respectively. Whereas the numbers of transferable embryos were 7.1 + 2.1, 7.3 + 1.9 and 5.6 + 1.3, respectively ; however, the differences were again not significant (p>0.05). The result of this research showed no significant difference in ovum recovery rate and the number of transferable embryos according to major metabolite concentrations in high-producing Holstein donor cows. However, it is considered that the failure of maintaining proper nutritional status would cause the fall in in vivo embryo productivity.