Maintenance of pregnancy in repeat breeder dairy cows by CIDR administration after breeding.
The aim of this study was to assess the effect of two periods of P4 therapy by CIDR on the 1st service Conception Rate (CR) of repeat breeder dairy cows. The cows were selected on the following basis: absence of dystocia, retained placenta and endometritis after the last parturition. They were inseminated according to the AM/PM rule relative to estrus onset and randomly assigned into 3 groups: (A) CIDR on day 5 after insemination that was removed on day 9 of the cycle (n = 40); (B) CIDR on day 5 after insemination that was removed on day 19 of the cycle (n = 36) and (C) untreated controls (n = 40). Pregnancy diagnosis was conducted by rectal palpation 45-55 days after AI in cows not observed in estrus. The difference in CR among the groups was analyzed by chi square analysis. The CR in groups A, B and C was 55, 41.7 and 30%, respectively and was greater (p<0.05) in treatment (A) cows than in control cows. In conclusion, repeat breeder cows in groups A and B benefited from progesterone supplementation, but significant effects of treatment for improvement of conception rate was seen in short treatment period (4 days treatment).
Ghasemzadeh-Nava
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H
Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Iran.
Kohsari
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H
Tajik
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P
D000818:Animals; D001947:Breeding; D002417:Cattle; D003612:Dairying; D005260:Female; D011247:Pregnancy; D018873:Pregnancy Rate; D011374:Progesterone / Q000008:administration & dosage*
D011374:Progesterone