Document Detail

Influence of concentration, duration and route of administration of melatonin on reproductive performance of spring-mated polypay and polypay-cross ewes.
MedLine Citation:
PMID:  3209497     Owner:  NLM     Status:  MEDLINE    
The effects of exogenous melatonin on reproductive performance of 737 Polypay and Polypay-cross ewes were evaluated during a late March and April breeding period. Different concentrations (2 or 10 mg) routes of administration (fed vs implanted) and durations of administration (20 or 40 d before breeding) were studied. Estrus was synchronized in all ewes using 60 mg medroxyprogesterone acetate (MAP) in a vaginal pessary. Number of mature ewes lambing/ewe present at lambing was increased (P less than .05) nearly 20% by implanting for 40 d with melatonin (75%) or by feeding either 2 (72%) or 10 mg (73%) melatonin for 40 d before spring breeding compared with untreated control ewes (54%) or ewes implanted for only 20 d before breeding (58%). Date of lambing, number of lambs born/ewes lambing and number of lambs born alive/ewe lambing were not altered significantly by treatments. Number of yearling ewes (n = 166 for ewes 1.5 yr old at lambing time) lambing/ewe present at lambing was lower (P less than .01; 26%) than that of mature ewes (n = 381, greater than or equal to 2.0 yr; 68%). We concluded that feeding 2 or 10 mg melatonin or implanting melatonin for 40 d enhanced reproductive performance and effectively overcame the restrictions of seasonality of breeding in mature ewes. In yearling ewes, 10 mg melatonin increased the number of ewes lambing.
J N Stellflug; J A Fitzgerald; C F Parker; D Bolt
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of animal science     Volume:  66     ISSN:  0021-8812     ISO Abbreviation:  J. Anim. Sci.     Publication Date:  1988 Aug 
Date Detail:
Created Date:  1989-02-23     Completed Date:  1989-02-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8003002     Medline TA:  J Anim Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1855-63     Citation Subset:  IM    
U.S. Dept. of Agriculture, Dubois, ID 83423.
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MeSH Terms
Administration, Oral
Drug Implants
Estrus / drug effects*
Melatonin / administration & dosage,  pharmacology*
Ovulation / drug effects
Pregnancy, Animal / drug effects*
Sheep / physiology*
Reg. No./Substance:
0/Drug Implants; 73-31-4/Melatonin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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