Combined administration of gonadotropin-releasing hormone, progesterone, and meloxicam is an effective treatment for the repeat-breeder cow.
In practice, the etiologic treatment of the repeat-breeder cow is nearly infeasible. In this study, we tested the hypothesis that a combined treatment would benefit the conception rate of repeat-breeder cows. The components of this regimen target ovulation defects, late progesterone (P4) rise, and premature luteolysis. In a 5-year period, 402 repeat-breeder cows were divided in five groups, and treatment regimens consisted of the following: gonadotropin-releasing hormone (GnRH; Group 1, n=115, 0.012mg buserelin im 4 to 6h before artificial insemination); P4 (Group 2, n=51, 100mg P4 intravaginally, on Days 5 to 7); meloxicam (Group 3, n=31, 0.5mgkg(-1), 24h(-1) melomicronxicam sc, on Days 16 to 18); GnRH+P4+meloxicam (Group 4, n=98); and no treatment (Group 5, control, n=107). Artificial insemination was conducted only after overt estrus; thereafter, the duration of the estrous cycle was assessed in all cows that were detected to return to heat. The conception and pregnancy rate was compared among groups. The proportion of cows that returned to estrus after artificial insemination did not differ among groups; the duration of estrous cycle was the shortest in Group 1 and the longest in Group 4. In Group 4, pregnancy rate was higher (P<0.05) than that of Groups 1 and 5 (35.71% vs. 20.00% and 17.76% for Groups 4, 1, and 5, respectively), but though numerically higher, it did not differ statistically from that of Groups 2 (27.45%) and 3 (22.58%). Our results imply that a multifaceted protocol has to be applied for the successful treatment of the repeat-breeder cow.
Amiridis
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Clinic of Obstetrics & Reproduction, Veterinary Faculty, University of Thessaly, 224 Trikalon Street, P.O. Box 199, 43100 Karditsa, Greece. gsamir@vet.uth.gr
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D000818:Animals; D001947:Breeding / Q000379:methods*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy*; D030762:Estrous Cycle; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000627:therapeutic use*; D007247:Infertility, Female / Q000188:drug therapy / Q000662:veterinary*; D000077239:Meloxicam; D011247:Pregnancy; D018873:Pregnancy Rate; D011374:Progesterone / Q000008:administration & dosage / Q000627:therapeutic use*; D013843:Thiazines / Q000008:administration & dosage / Q000627:therapeutic use*; D013844:Thiazoles / Q000008:administration & dosage / Q000627:therapeutic use*
D013843:Thiazines; D013844:Thiazoles; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D000077239:Meloxicam