Consumer protests over the injection of growth hormones to increase milk production in dairy cattle are based on emotion and not fact, says the director of Utah State University's Department of Animal, Dairy and Veterinary Sciences.
Robert Lamb told a biotechnology conference that a lack of education has caused the controversy over milk produced with the growth hormone, bovine somatotropin."There's no way to tell milk produced from cows receiving BST supplements," he said. "There's absolutely no difference in quality or composition. BST does not change the fat, protein or lactose."
Consumer fears that the hormone will be passed on through the cow's milk also are unfounded, he said.
"These growth hormones are different than steroids," he said. "BST is a naturally occurring protein that can be easily digested by humans."
What's more, injections of BST into dairy cattle have not increased BST levels in the milk. For these reasons, the Food and Drug Administration has said that milk and meat from cows being supplemented by BST are safe for human consumption on a trial basis.
Final approval will not come until the FDA determines whether hormone injections cause undue stress on the cattle. Long-term animal safety trials are now in progress, and approval could come within a year, he said.
Research on BST supplements has been going on at USU under Lamb's supervision for four years. Results have revealed that BST increased milk production 15 percent to 25 percent within 48 hours.
"Cattle being treated with BST have not shown observable health problems, and their offspring are the same size and condition as other calves," Lamb said. "But because cows are producing more milk, they might be under greater stress."
The growth hormone injections work because the cows require less feed to produce a pound of milk. Lamb's results indicate feed intake will increase 5 percent to 15 percent. But more energy from feed is directed into milk production rather than body maintenance.