Document Detail

Temporal trends in bull semen quality: a comparative model for human health?
MedLine Citation:
PMID:  19181314     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: A decline in human semen quality over the past 30-60 years has been reported in numerous epidemiological studies from the United States and Europe. We evaluated temporal trends in semen quality parameters in dairy bulls. The long-term management of dairy bulls for artificial insemination presented a unique opportunity to evaluate temporal trends in semen quality and explore this relationship as a potential animal model for reproductive abnormalities in humans. MATERIALS AND METHODS: Bull semen analysis data from 1965 through 1995 were collected from a large artificial insemination organization. Semen analyses from 12- to 18-month-old Holstein dairy bulls were included in the study and consisted of daily sperm concentration, daily ejaculate volume, total daily sperm output, percentage of sperm with normal morphology, and percentage of sperm with normal post-thaw motility. Multiple regression analysis, logistic regression, and general linear modeling were used to determine temporal trends over the 30-year period. RESULTS AND DISCUSSION: Semen quality appears to have declined from 1970 to 1980 or 1985 as manifested by declines in daily ejaculate volume, daily sperm concentration, and total daily sperm output. In contrast, sperm morphology and motility improved over the same period. In approximately 1980 or 1985, depending on the parameter, ejaculate volume, sperm concentration, total sperm, and motility improved. However, normal morphology began to deteriorate during this same period. Methodological inconsistencies over time introduce uncertainty in analyses of temporal trends in semen quality in this and previous human studies. However, changes in technology do not appear to be solely responsible for the temporal trends observed. The source of the decline in semen quality in the bulls studied is unknown. If the decline in semen quality were due to exposure to endocrine disrupting chemicals, then a continued decline or a leveling-off would be expected. Instead, a rise in semen quality was observed during the latter portion of the observation period.
Robert L Wahl; John S Reif
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Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2009-01-31
Journal Detail:
Title:  Environmental research     Volume:  109     ISSN:  1096-0953     ISO Abbreviation:  Environ. Res.     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-03-16     Completed Date:  2009-03-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0147621     Medline TA:  Environ Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  273-80     Citation Subset:  IM    
Division of Environmental Health, Michigan Department of Community Health, P.O. Box 30195, 201 Townsend Street, Lansing, MI 48909, USA.
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MeSH Terms
Endocrine Disruptors / toxicity*
Environmental Monitoring / methods*
Insemination, Artificial / standards,  veterinary
Linear Models
Models, Biological*
Semen / cytology,  drug effects*,  physiology
Semen Analysis
Sperm Count / veterinary
Sperm Motility / drug effects*,  physiology
Reg. No./Substance:
0/Endocrine Disruptors

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

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