Genetic manipulation of milk proteins and its consequences for the dairy industry.

Genetic selection of cattle by selective breeding patterns dates back to prehistoric times and has resulted in the diversity of breeds we see today. Selection in New Zealand has been for fat production earlier in the century, and more recently for protein production as well as fat. There is a lot of interest today in the naturally occurring variants of the milk proteins, as these can confer interesting differences in the molecular behaviour of the proteins as well as being correlated with compositional differences in the milk. Genetic modification holds great promise for the future in the dairy industry, but present constraints due to cost, lack of basic knowledge, and difficulty in producing genetically-modified calves, mean that only the biopharmaceutical area is likely to be affected in the near future. Coupled to this is an apparent lack of acceptance of food from genetically-modified animals by consumers. It will therefore need a change in public attitude as well as some development in science and technology before dairy products from genetically modified cattle become a commercial reality.