Profitability in Daughters of High Versus Average Holstein Sires Selected for Milk Yield of Daughters

Abstract

Data from 778 cows with 2,461 lactations through three generations of selection at the Iowa State University research herd were used to study differences between daughters of sires selected for high and breed-average Predicted Difference Milk. A profitability function, income minus expense, was calculated for each cow. A fixed, linear model was used to describe lifetime profitability. Daughters of high Predicted Difference Milk sires had 49% higher semen costs, 1% higher reproductive health costs, less than 1% fewer breedings, and less than 1% more reproductive examinations. They had 9% more respiratory costs, 6% more digestive costs, and 8% more skin and skeletal costs. Daughters of high Predicted Difference Milk sires produced 16% more milk, had 26% more mammary costs, and 42% more discarded milk costs. Disregarding breeding costs, they had 21% higher total health costs. Including breeding costs, total health costs were 32% higher. With 9% increased feed costs, they netted 18% more lifetime profit and 18% more profit per day of life. Use of a mixed model, which adjusted for fixed effects and included cows as random variables, showed daughters of high Predicted Difference Milk sires to have 12.5% more milk and 15.5% more profit per lactation. Number of breedings and reproductive examinations increased in later lactations and also in later generations as milk production increased in the daughters of high Predicted Difference Milk sires. © 1985, American Dairy Science Association. All rights reserved.