NZ researchers breed first hypo-allergenic milk producing cow

03-Oct-2012 - Last updated on 04-Oct-2012 at 14:00 GMT

Researchers in New Zealand have genetically engineered a dairy cow that produces hypo-allergenic high-protein milk.

Scientists at AgResearch’s Ruakura campus wanted to discover if they could produce milk which contained less beta-lactoglobulin (BLG) - milk protein known to be allergenic in infants.

Around 3% of infants are allergic to BLG, which is found in cow’s milk but not breast milk.

The process, which was first tested successfully on mice, was applied to a dairy cow – called Daisy. The resulting milk collected from Daisy contained no detectable BLG protein.

The study, Targeted microRNA expression in dairy cattle directs production of beta-lactoglobulin-free, high casein milk, was published in the Proceedings of the National Academy of Sciences in the United States (PNAS) journal.

Reducing BLG

“We were successful in greatly reducing the amount of beta-lactoglobulin (BLG), a milk whey protein which is not in human breast milk and which can cause allergic reactions,” said Dr Stefan Wagner, a lead author on the paper.

“Two to three percent of infants are allergic to cow’s milk, and BLG allergies make up a large part of that percentage.”

“People have long looked into reducing this enigmatic protein, or completely knocking it out, because there has been no definite function able to be assigned to it. So, we developed this scientific model to investigate the effect of knocking BLG protein out on the composition and functional properties of milk, and to determine whether the absence of BLG produces cow’s milk that is hypo-allergenic,” said Wagner.

In order to sidestep the two year delay in natural lactation, the cow’s milk was analysed following an induced lactation.

The resulting milk collected had no detectable BLG protein. Levels of casein proteins were also more than twice the level occurring in normal cow’s milk, researchers announced.

Commercial applications

The researchers have, however, played down any talk of commercialisation, stating that they do not “envision any practical application any time soon.”

They added that current GM regulations in New Zealand would not permit the commercial production of milk based on their process.

“This work is still very much at the discovery stage. We have shown it is possible to suppress BLG, but there is much more research to be done, and even if it does prove possible to do this on a larger scale, with New Zealand’s current legislation, it wouldn’t be possible to produce this commercially,” said a researcher document.