| Comparison of progestin-based protocols to synchronize estrus and ovulation before fixed-time artificial insemination in postpartum beef cows. | |
MedLine Citation:
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PMID: 17400969 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This experiment was designed to compare pregnancy rates in postpartum beef cows resulting from fixed-time AI (FTAI) after treatment with 1 of 2 protocols to synchronize estrus and ovulation. Cross-bred, suckled beef cows (n = 650) at 4 locations (n = 210; n = 158; n = 88; and n = 194) were assigned within a location to 1 of 2 protocols within age group by days postpartum and BCS. Cows assigned to the melengestrol acetate (MGA) Select treatment (MGA Select; n = 327) were fed MGA (0.5 mg x head(-1) x d(-1)) for 14 d, GnRH (100 microg of Cystorelin i.m.) was injected on d 26, and prostaglandin F2alpha (PG; 25 mg of Lutalyse i.m.) was injected on d 33. Cows assigned to the CO-Synch + controlled internal drug release (CIDR) protocol (CO-Synch + CIDR; n = 323) were fed a carrier for 14 d, were injected with GnRH and equipped with an EAZI-BREED CIDR insert (1.38 g of progesterone, Pfizer Animal Health, New York, NY) 12 d after carrier removal, and PG (25 mg of Lutalyse i.m.) was injected and the CIDR were removed on d 33. Fixed-time AI was performed at 72 or 66 h after PG for the MGA Select or CO-Synch + CIDR groups, respectively. All cows were injected with GnRH (100 microg of Cystorelin i.m.) at the time of insemination. Blood samples were collected 8 and 1 d before the beginning of MGA or carrier to determine estrous cyclicity status of the cows (estrous cycling vs. anestrus) before treatment [progesterone > or = 0.5 ng/mL (MGA Select, 185/327, 57%; CO-Synch + CIDR, 177/323, 55%); P = 0.65]. There was no difference (P = 0.20) in pregnancy rate to FTAI between treatments (MGA Select, 201/327, 61%; CO-Synch + CIDR, 214/323, 66%). There was also no difference (P = 0.25) between treatments in final pregnancy rate at the end of the breeding period (MGA Select, 305/327, 93%; CO-Synch + CIDR, 308/323, 95%). These data indicate that pregnancy rates to FTAI were comparable after administration of the MGA Select or CO-Synch + CIDR protocols. Both protocols provide opportunities for beef producers to utilize AI and potentially eliminate the need to detect estrus. |
Authors:
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D J Schafer; J F Bader; J P Meyer; J K Haden; M R Ellersieck; M C Lucy; M F Smith; D J Patterson |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2007-03-30 |
Journal Detail:
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Title: Journal of animal science Volume: 85 ISSN: 1525-3163 ISO Abbreviation: J. Anim. Sci. Publication Date: 2007 Aug |
Date Detail:
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Created Date: 2007-07-16 Completed Date: 2007-10-16 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8003002 Medline TA: J Anim Sci Country: United States |
Other Details:
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Languages: eng Pagination: 1940-5 Citation Subset: IM |
Affiliation:
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Division of Animal Sciences, University of Missouri, Columbia 65211, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Abortion, Veterinary Administration, Oral Animal Husbandry / methods* Animals Cattle / physiology* Dinoprost / administration & dosage, analogs & derivatives, pharmacology Drug Implants Estrus Synchronization / drug effects, methods* Female Fertility Agents, Female / administration & dosage, pharmacology* Gonadotropin-Releasing Hormone / administration & dosage Insemination, Artificial / veterinary Melengestrol Acetate / administration & dosage Ovulation / drug effects* Postpartum Period Pregnancy Pregnancy Rate* Progesterone / administration & dosage |
| Chemical | |
Reg. No./Substance:
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0/Drug Implants; 0/Fertility Agents, Female; 2919-66-6/Melengestrol Acetate; 33515-09-2/Gonadotropin-Releasing Hormone; 38562-01-5/dinoprost tromethamine; 551-11-1/Dinoprost; 57-83-0/Progesterone |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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