Effects of Bovine Somatotropin (bST) Administration Combined with Controlled Internal Drug Release (CIDR) on Embryo Quality and Pregnancy of Hanwoo (Korean Native Beef Cattle) during Commercial Embryo Transfer Program |
Ho-Jun Lee, Seongsoo Hwang, Jong-Taek Yoon* |
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Correspondence:
Jong-Taek Yoon, |
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Abstract |
Effects of recombinant bovine somatotropin (bST) on plasma hormonal concentration, embryo quality, and pregnancy rate were examined during the superovulation and synchronization treatment in donor and recipient cows. Hanwoos (Korean native beef cattle) were treated with controlled internal drug release (CIDR) combined with bST (CIDR+bST) or without bST (CIDR) as donor cows. The embryos recovered from donors were transferred into Holstein recipient heifers treated with bST (CIDR+bST) or without bST (CIDR) for synchronization. The correlation between IGF-I and P4 showed a positive pattern in the CIDR+bST group (r = 0.44, p<0.01), but a negative pattern was shown in the CIDR group (r = -0.59, p<0.02) at day 7 of estrous cycles. Although the number of recovered, transferable, and degenerated embryos was not different, quantities of grade 1 (excellent) embryos in CIDR+bST group were significantly higher than those of the CIDR group (p<0.01). The pregnancy rate was higher in the CIDR+bST recipient group compared to CIDR group (p<0.05), when the embryos were recovered from the donors treated with CIDR. However, the pregnancy was maintained highly in both recipient groups, when the embryos were produced by CIDR+bST treated donors. It can be concluded that bST administration combined with CIDR is an effective method for superovulation and synchronization treatment to stabilize plasma hormonal levels, to obtain excellent quality of embryos, and to get higher pregnancy rate. |
Keywords:
Bovine Somatotropin; Embryo Transfer Program; Corpus Luteum; Plasma Hormonal Level; Pregnancy; bST (Bovine Somatotropin); CIDR (Controlled Internal Drug Release); CL (Corpus Luteum); D (Donor); R (Recipient) |
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