Are there alternatives to pure breeding?

Pure breeding is the prerequisite for any systematic animal breeding. Scien tific results and practical experiences show that animals with high heteroz ygoty are optimally buffered against environmental and genetic stress. Syst ematic utilisation of heterosis effects is much more difficult in dairy ind ustry than in poultry and pig industry. Up to now, it has not been possible to compensate undesirable side effects due to the increasing production yi elds by simultaneous selection for fitness traits even in the most effectiv e AI breeding programmes with dairy cattle. Thus, in spite of the difficult ies, commercial crossings may be the most effective solution in high yieldi ng dairy herds. HILL (1971) listed a number of stipulations which have to be fulfilled in c ommercial dairy crossbreeding programmes. To day, rotational crossbreeding programmes with proven sires (Interbull-breeding values) may be the best ch oice. Two breed rotational crosses starting with Holstein cows and using pr oven Braunvieh (German Brwon-Swiss) or Fleckvieh (German Simmental) sires a re discussed.