A pig breeder wants to select for two traits: Weight and Feed intake. They have decided that they wish to increase weight whilst reducing feed intake. Both traits have the same heritability (0.3) and the same phenotypic standard deviation (2 units). The genetic correlation is 0.40 and the phenotypic correlation 0.30. The breeder has calculated the economic value on the two traits of +2 for weight and -0.5 for feed intake.

A selection index based on own performance is calculated and used to predict response to selection in one generation, which is 1.05 Kg for Weight and 0.25 Kg for Feed intake. The breeder has asked you a series of questions regarding the results.

A. What is a selection index used for in animal breeding?

B. What is the difference between economic values and predicted response?

C. Are the economic weights appropriate for the breeder's goal? Explain why the response for feed intake is positive.

D. Explain how an index could be designed such that there was no response for feed intake.