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Research Project:
Improving Genetic Prediction of Economic Merit of Dairy Animals
Location:
Animal Improvement Programs Laboratory
Title: Selection on Net Merit to Improve Lifetime Profit
Author
Submitted to: Journal Of Dairy Science
Publication Acceptance Date: April 29, 2004
Publication Date: October 1, 2004
Publisher's URL: http://aipl.arsusda.gov/publish/jds/2004/87_3125.pdf
Citation: Van Raden, P.M. 2004. Selection On Net Merit To Improve Lifetime Profit. Journal Of Dairy Science. 87(10):3125-3131.
Interpretive Summary: Genetic selection has made dairy cows more profitable. Terms defined by early animal breeders are still very useful and are now applied to very large populations. Selection indexes provided by USDA included yield traits beginning in 1971, productive life and somatic cell score in 1994, conformation traits in 2000, and cow fertility and calving ease in 2003. This latest revision should result in faster progress worth $5 million per year nationally, with improved health and fitness, but slightly less progress for yield. Inclusion of more traits provides breeders a more accurate summary of lifetime profit. Many other nations provide selection indexes similar to U.S. net merit.
Technical Abstract: Genetic selection has made dairy cows more profitable producers of milk by changing a number of income and expense traits. Yield and conformation traits are more heritable than longevity, fertility, and health traits, but many traits may deserve selection because of large economic values and coefficients of variation. Selection indexes provided with USDA evaluations included yield traits beginning in 1971, productive life and somatic cell score beginning in 1994, and conformation traits in 2000. In August 2003, cow fertility and calving ease were included in net merit calculations. Selection using the new formula should result in faster progress for several measures of health and fitness, but slightly less progress for yield. Breeders may prefer to select for fertility instead of longevity because cows have several fertility records but only one longevity record, which is incomplete until the end of life. Fertility and longevity evaluations have similar reliability even though the heritability of longevity is greater. Multiple selection indexes are needed for different production systems and markets; milk volume has positive value for fluid use, but negative value for cheese production. Breeding programs must consider future costs and prices, but these are difficult to estimate. Lifetime profit can be estimated more accurately if more traits are evaluated. Many other nations have derived selection indexes similar to U.S. net merit.
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Publications
Related National Programs |
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Related Projects |
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Increasing Accuracy of Genetic Evaluations for Calving Ease |
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Improving Identification, Reproduction, and Health in Dairy Cattle |
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Improving Identification, Reproduction, and Health in Dairy Cattle |
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Improving Identification, Reproduction, and Health in Dairy Cattle |
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Improving Reproduction and Health in Dairy Cattle Through Use of on-Farm Databases |
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Improving Identification, Reproduction, and Health in Dairy Cattle |
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Estimating Economic Contribution of Daughter Pregnancy Rate to Lifetime Net Merit |
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Effects of Heat Stress on Reproduction, Production, and Survival of Holsteins and Jerseys Or Holsteins and Brown Swiss in the Same Herd |
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Improving Fitness in Dairy Cattle by Facilitating the Initiation of a National Research Database for Health Traits |
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Estimating Daily Milk, Component Yield, and Scs from Individual Milking Data |
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Improving Prediction of Dairy Bull Genetic Merit Considering Heat Stress by Geographical Region |
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Genetic and Environmental Parameters for Yield Traits Across Varying Herd Sizes, Production Levels and Lactation Number |
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