Hi-tech drug 'puts more pus in milk'

MILK from cows given a genetically engineered drug to raise their yield contains more pus than does milk from those not treated, according to a report published today.

The authors, three British researchers, re-analysed data from eight trials conducted in the late Eighties and funded by Monsanto, the chemicals company that produces a commercially available version of the drug, called Posilac.

This is an artifical version of a growth hormone found in cattle, bovine somatotropin (BST).

The authors pooled data from 620 cows involved in the separate trials, and claim to have found a statistically significant difference between the numbers of white blood cells, or pus, in milk from BST-treated cows and the cell counts in milk from untreated animals. 'On average, BST treatment produced a 19 per cent increase in milk somatic cell counts relative to controls,' the authors say.

The new analysis, published in today's issue of the science journal Nature and peer-reviewed by an independent expert, will fuel debate over what has already proved a highly controversial drug. BST raises milk production by about 15 per cent, and has become the flagship product of the biotechnology industry. But possible health effects have become key issues.

In a statement issued last night, Tom McDermott, director of biotechnology communications at Monsanto, said the company had published the results of 'the largest data set ever reviewed on this subject' in the July 1994 Journal of Dairy Science.