Slim hips, easy milker
DAIRY cows with narrow hips have better shaped udders and are easier to milk, according to Bill Hobby, director of Network Genetics, Hilmar, California.
Hip width on a Holstein cow can vary up to 325mm (13in), claims Mr Hobby, whereas pin and thurl width only alter by 75mm (3in) and 50mm (2in) respectively.
"By turning the hips in and making them narrower the rear udder comes up high and tight as well as wide and uniform. That is a good shape and makes the cow easier to milk," he explains. "Ideally an udder should be uniform in height and width from top to bottom. It should be held tight to the body wall and give large amounts of milk.
"Our dairy men want cows to live longer, but they also want them to be able to make 68,000kg in five lactations," says Mr Hobby. "In Wisconsin there are dairymen who have bred for this characteristic. They have two-year-olds in their herds giving up to 20,000kg a year."
Thats 52kg to 54kg a day which is a lot of milk so they have to have wide rear ends."
Jersey bulls breeding true to the optimum thurl angle are Generator, Earl and Duncan. Holstein bulls include Harvest, and Mark Wayne.