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Genetic Correlations among Detailed Reproductive Traits, Traditional Reproductive Traits and Milk Production in Irish Dairy Cows
The objectives of this study were to estimate genetic parameters of detailed reproductive traits and to estimate genetic correlations between these traits and both traditional reproductive traits and milk production. Detailed reproductive traits, derived from ultrasound examination of the reproductive tract, included resumed cyclicity, cystic structures, multiple ovulation, embryo loss, and uterine score (1 to 4 based on the uterine environment). Data were available on 208,962 records from 88,288 dairy cows. Variance components and genetic correlations were estimated using repeatability animal/sire models. Heritability estimates for the detailed reproductive traits ranged from 0.001 (embryo loss) to 0.07 (cyclicity). Genetic correlations among the detailed reproductive traits varied from 0.05 to 0.74, between the detailed reproductive traits and traditional reproductive traits from 0.04 to 0.89 and between the detailed reproductive traits and production from 0.01 to 0.49, suggesting higher milk production was associated with poorer reproductive performance.
Keywords:
Correlation
Production
Fertility
