Issue |
Genet. Sel. Evol.
Volume 39, Number 4, July-August 2007
|
|
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Page(s) | 405 - 419 | |
DOI | https://doi.org/10.1051/gse:2007011 | |
Published online | 06 July 2007 |
DOI: 10.1051/gse:2007011
Genetic and environmental effects on semen traits in Lacaune and Manech tête rousse AI rams
Ingrid Davida, Xavier Druartb, Gilles Lagriffoulc, Eduardo Manfredia, Christèle Robert-Graniéa and Loys Bodinaa Station d'amélioration génétique des animaux, INRA, UR631, BP 52627, 31320 Castanet-Tolosan Cedex, France
b Physiologie de la reproduction et des comportements, INRA - CNRS UMR1291, 37380 Nouzilly, France
c Institut de l'Élevage, ANIO, BP 42118, 31320 Castanet-Tolosan Cedex, France
(Received 4 May 2006; accepted 22 February 2007; published online 6 July 2007)
Abstract -
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.
Key words: ram / semen / environmental factor
Correspondence and reprints: Ingrid.David@toulouse.inra.fr
© INRA, EDP Sciences 2007