Breeding Beef Germ Plasm Composites to Fit Special Environments

A long term breeding program has been designed to take advantage of the heterosis available in a six breed composite while developing a cow which can reproduce on crop residue. A controlled natural selection method has been developed for those reproductive traits which did not lend themselves to objective measurement. Reproductive efficiency and feed conversion will always be desirable traits in beef cattle. Intensive selection pressures were applied to the above traits during the initial generations of crossing to form the composite. Culling rates of 70% were used in the initial and backcross generations. The effectiveness of selection has been estimated by comparing the average reproductive rate of all the FI cows to that observed in the composite. Correlated responses to selection for reproduction have been observed between the reproductive traits and the production traits