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Rates of Milk Flow and Milking Times Resulting from Selection for Milk Yield1,2

Journal of Dairy Science
American Dairy Science Association
DOI: 10.3168/jds.s0022-0302(86)80438-6
  • Production Research Papers


Abstract Responses to selection for milk yield for rates of milk flow and times for milking were studied using data from an experimental herd of Holsteins. In 1964, foundation cows were paired by sire and randomly split into two genetic groups, selection and control. Four highest bulls for Predicted Difference milk were mates for selection cows each year and replaced annually. Twenty bulls near breed average for milk in 1964 were mated continuously to control cows. Beginning in 1972, milk yield at 15-s intervals was recorded by using a stopwatch and milk meter. Lactations for 130 selection and 162 control cows were observed over 10 yr. Selection cows did not differ from controls during first lactation for rate of milk flow but took longer to milk until stripping. When adjustment was made for milk yield at the observed milking, pedigree groups did not differ for milking time until stripping. Data from all cows suggested that rates of milk flow were also greater for selection cows. First parity heritabilities were .46 (peak rate), and .68 (milking time until stripping). Genetic and phenotypic correlations of milk yield with rates of flow and milking times were positive.

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