Suppose we are interested in the genetic change in two traits: Weight and Feed Intake. The relative economic values of the traits are 1 for weight and -0.3 for feed intake. Assume both traits have the same heritability (0.35) and the same phenotypic standard deviation (3 units). The genetic and phenotypic correlation coefficients are 0.4 and 0.25 respectively.
A breeder works out a selection index based on own performance and finds that the predicted response to selection in one generation is 0.58 Kg for weight and 0.16 Kg for feed intake. The actual index weights are 0.274 for weight and -0.038 for feed intake.
a. Are these selection responses in a desirable direction for both traits?
b. If an animal has an above average feed intake, would that help in obtaining a higher index value?
c. Explain why the response for feed intake is positive.
d. Can an index be designed that results in a null-response for feed intake but increase in weight? Explain your answer.
Suppose we are interested in the genetic change in two traits: Weight and Feed Intake. The relative economic values of the traits are 1 for weight and -0.3 for feed intake. Assume both traits have the same heritability (0.35) and the same phenotypic standard deviation (3 units). The genetic and phenotypic correlation coefficients are 0.4 and 0.25 respectively.
A breeder works out a selection index based on own performance and finds that the predicted response to selection in one generation is 0.58 Kg for weight and 0.16 Kg for feed intake. The actual index weights are 0.274 for weight and -0.038 for feed intake.
a. Are these selection responses in a desirable direction for both traits?
b. If an animal has an above average feed intake, would that help in obtaining a higher index value?
c. Explain why the response for feed intake is positive.
d. Can an index be designed that results in a null-response for feed intake but increase in weight? Explain your answer.
