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Relationships of Lifetime Profit to Sire Evaluations from First, All, and Later Records

Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061

H. D. Norman

US Department of Agriculture, Research Center, Beltsville, MD 20705

ABSTRACT

Sire evaluations from first, all, and later lactations for PD milk, fat, and dollars on 338 sires were used to predict deviated relative net income of individual daughters on a per day and lifetime basis. Eleven different relative net incomes, deviated from contemporaries, were calculated on 176,902 cows. Variation in individual daughter relative net income accounted for by sire evaluation was statistically significant but small (R² = .001 to .005). Progeny group average estimates of deviated relative net income could be predicted with reasonable accuracy (R² = .097 to .360). Models using PD dollars from first and later lactation evaluations had larger coefficients of determination for both per day and lifetime deviated relative net income measures than did models using milk and fat evaluations. Ability to predict progeny group averages for lifetime relative net income was superior (R² = .199 to .360) to the ability to predict progeny group averages for relative net income per day. Later lactation sire evaluations were more useful than evaluations based on first lactations in the prediction of total lifetime profit. Profit per day of productive life was predicted more accurately from first lactation evaluations than evaluations based on later lactations.

¹ Ascutney View Farms, Inc., Cornish, NH 03745.