Document Detail


Influence of light and photoperiodicity on pig prolificacy.
MedLine Citation:
PMID:  3910824     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In the wild pig mating activity is seasonal. The main breeding period is in late autumn but a second period may occur around April. It is known from other species that seasonal variations in breeding activity are mainly regulated by photoperiod. In the domestic pig seasonal influences on prolificacy still exist: for example, AI boars not only show decreased steroid synthesis, sperm counts and libido in summer compared with the optima which occur in winter but also a biphasic pattern with a transient increase in spring. In cyclic sows ovarian function may be affected with anoestrus mainly in summer and occasionally in February/March. Additionally ovulation rate may be lower in summer and the duration of oestrus prolonged compared with that in late autumn and winter. In consequence the interval from weaning to oestrus is prolonged in summer and mating during this season leads to lower conception rates and slightly smaller litters. Light programmes which extend the daily light period to a constant 15-16 h seem to be ineffective in improving reproductive characteristics of the sow but stimulate the sucking frequency of piglets and increase survival of piglets with a low birthweight. Simulation, in summer, of the decreasing photoperiod (naturally occurring in autumn) stimulates the reproductive characteristics of AI boars, optimizing testicular steroid production, libido and semen composition. Similarly, a programme of decreasing light (20 min decrease/week) from May to August removed the seasonal increase (June-August) of the weaning-to-oestrus interval which was 5.7 days (compared with 23.6 days for the controls). An interaction between photoperiod and puberty attainment seems to exist for male and female pigs. Further experiments with appropriate light programmes, however, are necessary to clarify this interaction.
Authors:
R Claus; U Weiler
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Journal of reproduction and fertility. Supplement     Volume:  33     ISSN:  0449-3087     ISO Abbreviation:  J. Reprod. Fertil. Suppl.     Publication Date:  1985  
Date Detail:
Created Date:  1986-03-11     Completed Date:  1986-03-11     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0225652     Medline TA:  J Reprod Fertil Suppl     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  185-97     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Androgens / biosynthesis
Animals
Estrus
Female
Fertility*
Light*
Male
Periodicity*
Pregnancy
Seasons
Sexual Maturation
Sperm Count
Swine / physiology*
Testis / metabolism
Testosterone / blood
Time Factors
Weaning
Chemical
Reg. No./Substance:
0/Androgens; 58-22-0/Testosterone

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


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