A rancher runs a closed herd (no use of outside animals) of breeding cattle. He

Question

A rancher runs a closed herd (no use of outside animals) of breeding cattle. He normally keeps and breeds the top 3% of his bull calves based on individual performance for yearling weight (YW). His sires average three years of age when their offspring are born. He is considering two female replacement strategies: 1) saving the top 20% of his heifers based on YW (Lf = 6.2 years), and 2) saving the top 60% based on YW (Lf = 3.2 years)

a. If heritability for YW is 0.50, and phenotypic standard deviation for YW is 60 lb, calculate the expected rate of genetic change in YW for each strategy.

            b. What elements of the key equation is the rancher experimenting with?

            c. What element appears to be the most important?

Explanation / Answer

?BV/t =    14.08 lb/yr

if and Lf are the key equation is the rancher experiment with.

The i affects L (i.e., by culling more cows that are aged or less productive, if increases, which potentially can translate into more genetic progress).

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.