Phenotypic relationship of yield and type scores from first lactation with herd life and profitability.

Milk records from Ayrshire, Brown Swiss, Guernsey, Jersey, and Milking Shorthorn cows that first calved between 18 and 35 mo were combined with scores for linear type traits collected before 43 mo during first lactation to study herd life and lifetime profitability. Profitability (discounted relative net income) was the value of milk, calves, and cow salvage minus fixed costs, operating costs, and cow depreciation costs. Cows were included if they appeared only in a single herd and if the herd remained on test for 72 mo after birth date of the cow. Phenotypic correlations were computed for milk and fat yields and for 14 type traits during first lactation with nine variables for lifetime performance from 3895 Ayrshire, 7997 Brown Swiss, 20,179 Guernsey, 71,731 Jersey, and 628 Milking Shorthorn cows. Multiple correlations for predicting discounted relative net income for the four breeds with the most data were 0.43 to 0.46 from milk and fat yields (linear and quadratic effects) during first lactation, 0.11 to 0.29 from final score, and 0.21 to 0.33 from all type traits. Type scores had considerably less predictive ability than yield during first lactation for predicting profitability and had limited predictability after yield was included. Final score increased multiple correlations only 0.00 to 0.02 above that for yield for the same four breeds. Final score plus 13 type traits (linear, quadratic, and interaction effects) increased multiple correlations only 0.02 to 0.04 above that for yield. Because of the limited value of some of the linear type traits, an effort should be initiated to eliminate them from programs of breed associations.