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Genetic Parameters of Days Open and Protein Yield Across Lactations for the Uruguayan Holstein Population
Fertility traits are highly affected by environmental factors, and unfavorably related to production. In order to include days open (DO) in a selection index it is necessary to estimate its genetic correlation with the rest of the traits in the index. The aim of this work was to estimate the genetic relationship between DO with protein yield (PY) across first, second and third parity. Low heritabilities for DO (0.018 - 0.033) and moderate for PY (0.18 - 0.23) were found. Genetic correlations among DO (0.42-0.70) at different parities suggest considering them as different traits; on the contrary, genetic correlations among PY in different parities were strong (0.74-0.83). Genetic correlations between DO and PY varied from 0.05 to 0.65. DO must be considered in animal selection analyzed individually by parity.
Keywords:
Fertility
Dairy cattle
Genetic correlation
