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Journal of Dairy Science Vol. 55 No. 12 1726-1734
© 1972 by American Dairy Science Association ®
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Type Appraisal: III. Relationships of First Lactation Production and Type Traits with Lifetime Performance

H. D. Norman1 and L. D. Van Vleck

Department of Animal Science, Cornell University, Ithaca, New York 14850

ABSTRACT

Phenotypic and genetic correlations were estimated between 48 type appraisal traits and first lactation milk production to determine the importance of appraisal traits in a breeding program from 5,024 records from the New York type appraisal program. Most phenotypic correlations among the type traits were near zero. Depth of udder was the appraisal trait having the highest correlation with first lactation milk (.27) and fat (.23). Multiple correlations of all appraisal traits with first lactation milk and fat were .44 and .40.

Correlations with lifetime variables were calculated from 2,068 records meeting time qualifications. Of the first lactation variables, milk yield had the highest correlation with lifetime milk (.34), and fat yield had the highest correlation with number of lactations (.21). All appraisal traits combined were as effective as production variables in predicting number of lactations.

Genetic correlations suggested that bulls that sire daughters with high production tend to sire daughters with weaker udder attachments. High genetic correlations between first lactation production and lifetime performance support the utility of selection on first lactation production.

FOOTNOTES

1 Present Address: Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, Maryland, 20705.






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Copyright © 1972 by the American Dairy Science Association ®.