The protein structures in milk are called “caseins”. Each form is a result of the animal
possessing a sequence of genes to produce it.
“Kappa Casein” affects cheese curd formation (BB K/C is preferred for
higher cheese yields)—“Beta Casein” affects immune function and how proteins
act after ingestion.
Keith Woodford (an agricultural research professor at
Lincoln University in New Zealand) wrote a book in 2007 titled Devil in
the Milk—reviewed in “Acres USA”, promoted by the Weston Price
Foundation - which linked one Beta Casein gene variant (A1) with a host of
current health issues: heart and arterial disease, autism, type 1 diabetes, and
schizophrenia. A1 variant is a mutation
first found in Northern European and North American dairy cattle, while the A2
variant is still primary to Southern European, African and Asian cattle. (There are in fact 12 gene variants of
Beta casein; only three of significant frequency. The original A2 variant is the basis for
the wholesome reputation of “milk”. The
fact of A1’s existence could destroy this hard-fought reputation, if promoted
by vegan activists.)
The mutated fragment is called “beta casomorphin 7” which
is a powerful opioid (narcotic) as well as an oxidant, and Dr Woodford’s book
quotes over 100 research papers to assemble the evidence. BCM-7 is now associated with lactose
intolerance and auto-immune diseases (type 1 diabetes is such a disease).
Distribution within breeds
Known dairy breeds vary in the proportion of A2 (“good”)
to B (“OK”) to A1 (“bad”) alleles possessed.
Guernsey: (1991 study) 88% to 97%
A2: 1% to 2% B:
1% to 6% A1
(USA cows)
Jersey: (1991) 49% to 52% A2:
29% to 37% B: 9% to 22% A1
(USA cows)
(1997) 59% A2: 29% B: 12% A1
(New Zealand)
(1990) 58% to 65% A2: 35% B: 7% A1
(Denmark)
Holstein: (1990-1991) 24% to 62%
A2: 1% to 6% B:
31% to 66% A1 (USA)
(1997) 51% A2: 3% B: 46% A1
(New Zealand)
(1997) 47% to 60% A2: 2% to 10% B: 40% to 47%
A1 (Europe)
Fleckveih: (1997) 56% to 63% A2: 15% B: 19% to 34%
A1 (Germany)
Ayrshire: (1997) 49% to 53% A2: - - 43% to 51% A1
(Finland & NZ)
(1992) 28% to 40% A2: 1% B: 60% to 72%
A1 (USA & UK)
Euro Red: (1997) 23% to 53% A2:
1% to 6% B: 46% to 71%
A1 (Sweden et al)
Consequences of the distribution of Beta Casein knowledge
The organic dairy industry is rapidly
embracing the A2 vs A1 Beta casein difference, as it provides an added basis
for justification of a premium product price.
Stoneyfield Yogurt and the Organic Valley marketing
cooperative are both encouraging their supplier grazing farms to test their
cows in preference for A2 carriers, and to breed accordingly, exclusively to
A2A2 sires. (Some earlier research
suggested that grass-based dairy nutrition programs enhance the production of
the A2 Beta casein benefits.)
Testing your cows for the Beta casein
gene markers is costly ($22-$30 per sample) but possible (the A2 Corporation of
New Zealand has lab agents in Oregon and northern Michigan)—in perspective, it
is less than the annual cost of entering a cow on DHIA for one year. Currently, the only AI system publishing
Beta Casein markers on their sires is LIC New Zealand (available
through us, distributed by Taurus in the USA) but we would anticipate other
AI systems to test sires of interest as farm demand increases.
How hard is it to breed for
A2 and away from A1
beta casein?
Until all AI sires are tested and
their markers published, it will be difficult.
The “safe” route is to focus on the LIC New Zealand sires
(many of which were recently “aAa” analyzed) because you can select on known
possession of A2A2. If you milk
Guernseys you hardly have to worry—if you milk Jerseys, in two generations you
could likely eliminate the A1 presence (only 7% to 22% frequency), as these
gene variants are simple alleles (not dominant vs recessive) thus selecting in
favor of one consistently reduces the other in frequency. If you milk Holsteins, it may take three or
four generations because the level of A1 is three times as high as randomly
distributed. (You will note that some
of the worst A1 frequency is in the Euro Red breeds that have been popularized
in crossbreeding.)
Cross breeding is no substitute for
selection on the gene marker.
Those whose milk production system and cattle marketing has been
promoted on “grass adaptation” and “healthier crossbred cows” are not in any
way prepared to claim milk product superiority under A2 vs A1. In this situation, it is your choices in
sires—not choices in breeds—that will determine where you start, and how
quickly you get where the market may influence you to go.
But I prefer the highest TPI or Net Merit sires—why pay any attention to this stuff?
The definition of insanity is to continue to do the same
thing you have always done, while expecting a different result than you have
always received. What has a focus on
“genetic value” given us? More milk per
cow lactation—but fewer lactations:
lower average milk components, thus lower milk prices: shorter herdlife, thus higher replacement
overhead: slower fertility, thus more
reproduction expense;
extreme physiques, thus more hoof
trimming and stall injury expenses.
Genetic value has no “value” unless you are able to harvest a margin
of profit over all input costs.
Developing markets for milk from herds that will dedicate to selection
on A2A2 genetics promise some serious price premiums based not on emotion, but
on science.
A1 vs A2 is just the first of what may
be many examples of why Genomics could be our most powerful selection
tool, but by only using it to estimate PTA values, we have trivialized
its true potential. Those who are
locked into conventional volume-based pooled “commodity milk” marketing have
nothing to be gained from a focus on A2 selection today—but the impact of this
knowledge on milk’s consumers, as it gains traction in the media’s oversight on
food issues, could be a worse blow to “generic jug milk” than the anti biotech
reaction to rBST—because we cannot quit using it overnight to satisfy a market
demand.
Short term strategies
The frequency in the Kiwi cow population does not appear
to be significantly above North America’s frequencies – thus we should be able
to identify A2 carriers in the USA and Canada. Study the lesson and encourage
dairy leadership to become proactive in addressing what may be a future
opportunity.
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