A report from New Zealand company AgResearch says that their scientists have produced a cow whose milk is both very low in 'beta-lactoglobulin' (BLG) and has more caseins, making it both safe to drink for children with milk allergies and even more nutritious than normal milk.
Milk allergies affect about 2-3% of children, and while most outgrow the allergy by the time they are 5 or 6 years old, some continue to suffer from these allergies their entire life.
The scientists modified unfertilized cow embryos with specific strands of Ribonucleic acid (RNA), which they they found could switch off the specific genes that control BLG production, and then implanted those embryos into mature cows. After an initial failure, the second attempt resulted in a healthy female calf.
Using hormones, the scientists caused the calf to produce milk, and when they tested it, they found that it contained only 4% of the normal amount of BLG found in cows' milk, and twice the normal amount of caseins. They believe that if they are able to breed this cow, they may be able to provide milk that is a safe alternative for babies that are allergic, when breastfeeding is not an option (Note: human breast milk does not contain beta-lactoglobulin).
The next stages of the research will be to breed the cow and see if its calves retain the ability to produce the low-BLG milk.