K.F. Ng-Kwai-Hang, professor of animal science at McGill University has spent the last 25 years studying the genetics of cows and their effect on cheese and has recently identified which make the best cheese.
"There are more than 100 different breeds of cows. However, the best milk producers are Holsteins," said Ng-Kwai-Hang. "Within a specific breed, the milk these cows produce is not the same - it differs in its fat, protein and lactose content."
This means that cheese made from this milk will also differ in its composition and the taste.
"Basically, cheddar cheese can be made from all milk, but the taste and quality will be different from breed to breed and also within a breed," he said.
Ng has identified the role of specific milk protein genes that affect cheese yield, composition and quality. He and his research team have found that small changes or mutations in the DNA of certain genes lead to changes in the protein which results in dramatic changes in the cheese.
Their findings show that a mutation in the particular protein, the kappa-casein, is associated with a higher yield of cheese and one which is better quality.
"By looking at the genetic profile of cows, we are able to predict which one will produce the best cheese."
According to Ng, in addition to the two genetic variants for kappa casein, there are about 50 known milk protein gene variants and they have diverse effects on dairy product production.
"Because the genetic variants are inherited according to simple Mendelian rules, it is possible to breed for specific variants," says Ng. "We are seeing this already where breeding programs are in place to increase the frequency of the B type of kappa-casein in cow populations in order to improve the milk quality and its cheese making characteristics."
Cheese in general in currently winning more favor with Americans than it has in the past. The Wisconsin Milk Marketing Board said in December last year that the country has increased its per capita consumption of cheese from 23 pounds in 1985 to 31 pounds in 2003. Analysts forecast that by 2013 this figure will have reached 33 pounds.