Question

A rancher has a herd of 1/2 Red Angus, 1/4 Angus, 1/4 Hereford cows (daughter of red angus sires and angus x hereford damns). She plans to mate her cows to 1/2 Charolais, 1/2 Angus bulls. Assume F1 individual hybrid vigor for weaning weight is 30 lbs and F1 maternal hybrid vigor for weaning weight is 48 lbs. Phenotypic means for weaning weight in the purebread populations are 600, 600, 550, and 675 lbs, for Red Angus, Angus, Hereford, and Charolais, respectively. a. Assuming all four breeds are unrelated, calculate the amount of individual, maternal, and total hybrid vigor for weaning weight that is retained in this cross. b. Predict the weaning weight phenotypic mean for the cross bred calves.

Answer 1

a. individual retained hybrid vigor = 30

maternal retained hybrid vigor = 48

total retained hybrid vigor = individual + maternal

=30 + 48 = 78

b. Composition of the crossbred calf =

weighted mean average weight ignoring the RHV =

= 615.25

Adding RHV = 615.25 + 78 = 693.25 lbs