We do not know when cows will start to produce chocolate milk or strawberry milk (perhaps when they will cross a strawberry with a cow...), but scientists are already on the way to fill the pastures with cows that produce skimmed milk.

New Zealand researchers have found that there are cows whose genes enable them to directly produce skimmed milk. These genes can be selected to deliver entire herds of cows from which skimmed milk could be milked.

Geneticists are also planning to obtain commercial herds producing milk with special traits required to make a butter that is spreadable straight from the fridge. They have already detected one female in the New Zealand herds carrying the right genes and a commercial herd could be available by 2011. This milk would be poor in saturated fats and rich in polyunsaturates and monounsaturated fats, an achievement that would change entirely the dairy industry.

"The New Zealand approach could be used to breed cows that still produce full-fat milk but with only the good fats, which could swing things back in favor of full-fat milk. In the UK, for example, only 25% of milk sold is full fat. In future if whole milk can be made to contain unsaturated fats - which are good for you - then it might mean that people change back to whole milk products. The big thing about dairy products is taste, so this would be a way of giving the benefits of taste without the disadvantage of saturated fats," said Ed Komorowski, technical director at Dairy UK.

Producing skimmed milk from full milk also generates a lot of fat waste, a costly leftover.

"If you can genetically produce milk without fat then that may turn out to be a very good solution to what might later be a big disposal issue. However, that although the lower-fat milk may be healthier, it will be interesting to see how much milk the cows actually produce. " said Komorowski.

The skimmed milk producing cows were detected when biotech company ViaLactia checked the array of milk compositions across the livestock of 4 million New Zealand cattle. New Zealand dairy firm Fonterra has already processed dairy products from the milk of the skimmed milk producing cow and they keep the normal flavor.