Plasma progesterone profile in ovariectomized beef cows after intra-vaginal insertion of new, once-used or twice-used CIDR.
Objective of this study was to show plasma progesterone concentrations in ovariectomized beef cows after treatment with new, once-used and twice-used controlled internal drug-releasing devices (CIDRs). Four ovariectomized beef cows were used for the experiment. Plasma concentrations of progesterone were quantified using a validated ELISA. The CIDR was inserted into vagina of cows by using a standard CIDR applicator and then removed 7 days after insertion. One week later, once-used CIDR was inserted and removed on day 7. Twice-used CIDR was, then inserted at an interval of 7 days. Mean plasma concentrations of progesterone 24 h after new CIDR insertion was 4.0 +/- 0.1 ng/ml, which thereafter decreased gradually to 1.4 +/- 0.1 ng/ml at day 7. In cows treated with once-used CIDR or twice-used CIDR, mean plasma progesterone concentrations at day 1 were 2.4 +/- 0.2 or 1.8 +/- 0.2 ng/ml and 1.0 +/- 0 or 0.9 +/- 0.1 ng/ml at day 7 respectively. The results suggest that once-used CIDR may be still effective to produce luteal phase progesterone concentrations in plasma in non-suckling beef cows.
Laboratory of Theriogenology, Department of Veterinary Medicine, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan.
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Long
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Yoshida
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Nakao
D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle / Q000097:blood*; D016503:Drug Delivery Systems / Q000295:instrumentation*; D005260:Female; D010052:Ovariectomy; D011374:Progesterone / Q000008:administration & dosage* / Q000097:blood*
D011374:Progesterone