Project Number: 1265-31000-096-04
Project Type: Specific Cooperative Agreement

Start Date: Jul 26, 2004
End Date: Dec 30, 2008

Objective:
To determine if adjustment of lifetime income for premature or delayed culling reduces the economic importance of PL uniformly under different patters of net income; to determine if the frequency and magnitude of production beyond 305d varies over time, across breeds, and with the age of the cow; to determine an economically sound method to expand the measure Productive Life (PL) to include productive days beyond 305; to determine an optimum method to predict the estimate of the new expanded measure of Productive Life for cows that are still alive; and to re-evaluate the economic weights for the traits in the merit indexes with the inclusion of the new measure of Productive Life.

Approach:
The estimate of the economic weight for the current measure of productive life in our initial work using lifetime RNI was exaggerated. The impact of adjustment of RNI for opportunity cost on the economic importance of traits in the merit indexes will be examined under different economic conditions (High and low average profit resulting from different costs per day and replacement costs); the proportion of total lactation production after 305d will be analyzed to determine the impact of breed (Holstein and Jersey), level of production, and trends over time; the value of days beyond the 305d currently included in the measure of PL will be determined using the Relative Net Income (RNI) method originally developed at AIPL and the form of the measure adjusted for opportunity developed at VA Tech under different economic conditions (High and low average profit).