Is A2 Milk about to go Mainstream?
There has been lots written recently on the topic of A2 Milk. What more to add then? Well it certainly turned a few heads when the New Zealand-based multi-National, Fonterra, recently announced a new strategic alliance with the A2 Milk Company brand.
One presumes that Fonterra will now begin conversations with its farmers to source A2 milk in New Zealand, to help meet the growing demand for A2 milk products. No doubt, the conversations will already be taking place with processors in Canada too.
A quick review of beta casein genetics first: Beta casein is a protein made up of a chain of 224 amino acids, that is responsible for around 30% of all milk proteins. There are two main versions of beta casein: A1 and A2, and although the A1 version has only one amino acid that is different from the A2 version, the digestion of dairy products from A1 and A2 beta casein proteins does differ. With the two variants A1 and A2, it means that cows can be A1A1, A1A2, or A2A2. Interestingly, and an important distinction from many other single gene traits like coat colour or polled genetics, neither variant dominates over the other. Cows that are A1A2 produce a combination of A1 and A2 beta-casein. When we say cows are “A2”, it means that they carry double copies of the A2 variant and thus produce no A1 beta-casein in their milk. A cow that is A1A2 on the other hand has copies of both alleles and has an equal chance of passing on the A1 or A2 variant to her calf. Mating her to a bull that is A2A2, would produce an A2A2 calf 50% of the time and A1A2 the other 50%.
Approximately 35% of Holstein sires are homozygous for the A2 variant, half have an A1A2 genotype while the remaining 16% of sires are homozygous for the A1 variant. Jersey, Brown Swiss and Guernsey breeds all enjoy a higher frequency of the A2A2 genotype but Increasing selection for the A2 allele in the Holstein breed is quickly reducing the gap.
As producers you might think it a long shot that individual farms might gain a premium for guaranteeing provision of 100% A2 milk, or that it would be too difficult to get there, but in the era of genomic testing, it is not difficult to imagine herd owners who have selected for the trait and have 50% A2A2 cows now taking steps to get to 100%.
While the science on the benefits of A2 milk is still not so clear cut, what is clear is that the marketability of the A2 brand is quickly growing. Hence a growing number of producers are not simply giving preference to A2A2 sires, but some are making it an exclusive decision. A2 milk has moved beyond simply being the next thing – Fonterra’s alliance will take A2 milk mainstream to a point that A2 milk can no longer be passed off as simply a fad. Ask your WestGen Genetic Advisor for a complete list of your A2 breeding options.