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Open Access

Genetic and environmental effects on semen traits in Lacaune and Manech tête rousse AI rams (Open Access publication)

  • Ingrid David1Email author,
  • Xavier Druart2,
  • Gilles Lagriffoul3,
  • Eduardo Manfredi1,
  • Christèle Robert-Granié1 and
  • Loys Bodin1
Genetics Selection Evolution200739:405

Received: 4 May 2006

Accepted: 22 February 2007

Published: 6 July 2007


Data from 51 107 and 11 839 ejaculates collected on rams of the "Lacaune" and "Manech tête rousse" breeds, respectively, were analysed to determine environmental and genetic factors affecting semen production traits (ejaculate volume, semen concentration, number of spermatozoa and motility) in young (≤1 year) and adult (≥2 years) rams. Fixed effects and variance components were estimated using multiple trait animal models within each breed. For all traits, the main environmental effects identified were year, season, number of ejaculations, daily variation, interval from previous to current collection and age. Heritability estimates were moderate for volume, concentration and number of spermatozoa (0.12 to 0.33) and lower for motility (0.02 to 0.14). Genetic correlations between ages differed from 1 for all traits (0.14 to 0.90), indicating that semen characteristics corresponded to different traits in young and adult rams. Genetic and phenotypic correlations among traits within age category were globally similar for the different breeds and categories of animals.


ramsemenenvironmental factor

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Authors’ Affiliations

Station d'amélioration génétique des animaux, INRA, UR631, Castanet-Tolosan Cedex, France
Physiologie de la reproduction et des comportements, INRA – CNRS UMR1291, Nouzilly, France
Institut de l'Éevage, ANIO, Castanet-Tolosan Cedex, France


© INRA, EDP Sciences 2007