Date of this Version
Correlations were computed between pairs of first-lactation milk records of unrelated Holstein cows in New York, where the records were made in the same herd and same year-season of freshening, and in the same herd but different year-seasons of freshening. Records were expressed as deviations from herd-mate averages. The average correlation between pairs in the same herd-year-season was .01. The average correlation when the pair of records was made one season apart was .08, and two seasons apart was .06. The pattern of correlations between a pair of records made more than 3 or 2 yr apart appears to be unpredictable.