Date of this Version
The expected change in dollar return from incorporating milk, fat, and protein records in a selection index (Index 1) was compared to that from an index utilizing just milk and fat records (Index 2) under pricing systems paying for milk, fat, and protein.
Dollar return 1 was superior to dollar return 2 when there was either no payment for protein or high payment for protein. For sire selection the expected changes in dollar return for the two indices were equal at a price for protein of $.88 per kg whereas for cow selection the returns were equal at a protein price of $2.65 per kg. At all other protein prices for both sire and cow selection, dollar return 1 exceeded dollar return 2.
Economic analyses of the costs and potential benefits of dollar return 1 compared to dollar return 2 were made for a variety of protein prices and costs of protein testing. Selection programs leading to dollar return 1 have a small economic advantage over those programs for genetic improvement leading to dollar return 2 when the cost of measuring protein is low or nil. Testing costs above $.01 per cow per month overwhelm the difference in economic return. Furthermore, realistic payments for protein lead to less economic advantage than no payment. Measuring protein has its greatest advantage at unrealistically high prices for protein. Increasing the genetic trend in milk yield above 45 kg will increase the economic feasibility of protein testing.