Correlations Among Records of Unrelated Cows in the Same Herd and the Same and Different Year-Seasons

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.