The effects of heterosis are the opposite of the effect of inbreeding depression. At each location of the pairs of chromosomes the two genes are much less likely to be identical with crossbreeding than with same-breeding matings. The heterosis will be an extra benefit on top to the parent advantage and is especially valuable for traits like vitality, fertility, disease resistance and health.
Complementarity breeds
Effective crossbreeding begins with two superior breeds. These breeds must complement each other well and must independently have a large enough selection base to continue their own unique breeding goals. Bringing together two breeds with desirable genes is called complementarity. A crossbreeding program should be well planned and organized and should use the best bulls from breeds that suit your conditions.
NRF for health and fertility
The Norwegian Red (NRF) is a high producing dairy cow that has been selected for health and fertility traits for the past 30 years. The NRF is a breed that decreases costs through lower calf mortality rates, higher female fertility and lower disease incidence. The NRF also carries the polled gene, which reduces calf setbacks and dehorning labour and materials.