Animal Science Department


Date of this Version

January 1969


Published in Journal of Dairy Science. Copyright © 1969 American Dairy Science Association. Used by permission.


The percentage of 40 or more daughters having four lactations of 81 New York Holstein artificially insemination sires was correlated with the percentage of daughters in 66 type categories measured in the first lactation and their average first-lactation milk yield. Multiple regression on these type and production traits accounted for 92% of the variation in percentage of daughters having four lactations. A subset of 33 traits accounted for 82% of the variation. Traits with the largest standard partial regressions for longevity were milk production (.41), udder edema (.87 and .71), deep body (.53), medium upstandingness (.41), fore udder attachment (--.86 and -.67), deep udder (-.73) and udder halving (-.64 and -.75). Traits having the largest correlations with the percentage of daughters having four lactations were: first-lactation milk (.54), plumb rear teat position (.38), sharp dairy character (.35), no breeding trouble (-,30), intermediate thurls (.26), typical head (.25), and fast milking speed (.25).