Post by cddexter on Dec 16, 2013 23:53:07 GMT -5
This article was published on page 11 of Issue 78 Winter 2008. I have a long standing permission to reprint from the AU Bulletin. Here is what was printed.
I first heard of A2 milk a little over a year ago. It intrigued me. The more I read the more I became interested. A2 milk is milk that does not contain A1 beta-caseins.
I read a lot of reports of health risks associated with A1 beta-caseins in milk. What I read led me to believe that the A1 beta-casein had been introduced into the dairy herds within the last century. Holsteins seemed to be at the centre of the controversy. From that, I surmised that primitive breeds, such as Dexters and beef breeds such as Herefords, stood a good chance of being free of the A1 beta-caseins and would therefore produce A2 milk. Breeds that had not been outcrossed to commercial dairy cattle should be safe.
Guesses and assumptions aren’t good enough for me so I began to try to discover if my Dexter cattle would give A2 milk
I spent most of the next year finding a way to have my herd tested. I fully expected every one of my cattle to test positive for A2 milk. I used an intermediary who does not want to be identified.
Of the seven Dexters samples submitted, five had tested CC positive for A2 and two had tested AC positive for A2. CC means that the animal is homozygous for A2, AC means that the animal is heterozygous for A2.
My first thought was, ‘Where did the A in AC come from?” My herd is comprised of all fullblooded Dexter stock, with the majority of them DBNA parentage verified. One of the AC cows was DNA tested for parentage. The other AC cow and one of the CC cows has not yet been DNA parentage verified. As far back as it is possible to trace my cattle’s ancestry, there is no instance of an animal that has ever been known to have been outcrossed. Parndon Bullfinch appears in all their pedigrees at some point, as he does in a great many US Dexters.
The mechanics of A2 versus A1 milk producers is this: A CC cow will produce A2 milk that is completely free of A1 beta-caseins. An AA cow will produce a quantity of the A1 beta caseins in her milk. An AC cow will produce fewer A1 beta caseins in her milk than an AA cow. Probably half as many, but I haven’t been able to find where anyone has published figures for this.
The test tells us exactly what kind of milk the tested cow will produce. The test also tells us what kind of genes the CC bull will p-ass on to his progeny. A CC cow mated to a CC bull will produce all CC offspring from that paring. If either of the parents is AC, then the odds of a CC offspring drop to 50%. If both of the parents are AC, the odds of having a CC offspring drop to 25%. AA parents cannot produce any CC or AC offspring.
It is not possible to trace the A2 milk genes upward in the pedigree. A CC animal could have come from two AC parents. The only thing we can know is that neither of the parents was AA. One of the parents of an AC animal could have been an AA, but it’s just as likely that one of the parents was a CC.
All of the Dexters I had tested are fullblooded Dexters, registered with the American Dexter Cattle association. Some of them are dual registered with the Purebred Dexter Cattle Association of North America.
They are: Brenn of Paradise, ADCA 016376, CC, a black horned bull, born November 21, 2004. He is DNA parentage verified. His chondro test is pending.
Windridge Bantrybeth, ADCA 11327, CC, a black, horned cow, born June 9, 1996. DNA parentage verified.
Jam’s Leahtata, ADCA 018689, CC, a black, horned heifer, born May 10, 2005. DNA parentage verified.
Jam’s Lorelaidy, ADCA 018691, CC, a black, horned heifer, born June 2, 2005. DNA parentage verified.
Jam’s Irish Mist, ADCA 017922, AC, a dun, horned cow, born March 27, 2006. DNA parentage verified.
Sunrise Lizzie, ADCA 019164, AC, a black, horned heifer, born February 8, 2007.
I’ve lately found some things to read that hint that the A! Beta-caseins may have been around much longer than a hundred years. It was only the advent of artificial insemination that spread it around the world. Asian cattle (Bos Indicus) don’t have it. It doesn’t cross to them.
The United States Department of Agriculture is currently undertaking a project to map out nearly 5000 DNA markers in cattle. Currently, our DNA tests use no more than 20 markers. I’m contributing tail hairs from some of my cattle to the USDA project. Eventually, they will be able to decipher the cattle genetic code to the point that they can tell what breed it is. That will be great.
A lighter note: I picked Benn’s name from a list of Irish boy’s names. It means “Prince”. It’s also my mother-in-law’s name in a way. Her maiden name was B. Renn.
“Always leave ‘em laughing!” (Jimmy Durante)
Now I have a question. As written, "It doesn't cross to them." Asian cattle (Box Indicus) cannot carry an A1 gene. Do you really mean this? c.
I first heard of A2 milk a little over a year ago. It intrigued me. The more I read the more I became interested. A2 milk is milk that does not contain A1 beta-caseins.
I read a lot of reports of health risks associated with A1 beta-caseins in milk. What I read led me to believe that the A1 beta-casein had been introduced into the dairy herds within the last century. Holsteins seemed to be at the centre of the controversy. From that, I surmised that primitive breeds, such as Dexters and beef breeds such as Herefords, stood a good chance of being free of the A1 beta-caseins and would therefore produce A2 milk. Breeds that had not been outcrossed to commercial dairy cattle should be safe.
Guesses and assumptions aren’t good enough for me so I began to try to discover if my Dexter cattle would give A2 milk
I spent most of the next year finding a way to have my herd tested. I fully expected every one of my cattle to test positive for A2 milk. I used an intermediary who does not want to be identified.
Of the seven Dexters samples submitted, five had tested CC positive for A2 and two had tested AC positive for A2. CC means that the animal is homozygous for A2, AC means that the animal is heterozygous for A2.
My first thought was, ‘Where did the A in AC come from?” My herd is comprised of all fullblooded Dexter stock, with the majority of them DBNA parentage verified. One of the AC cows was DNA tested for parentage. The other AC cow and one of the CC cows has not yet been DNA parentage verified. As far back as it is possible to trace my cattle’s ancestry, there is no instance of an animal that has ever been known to have been outcrossed. Parndon Bullfinch appears in all their pedigrees at some point, as he does in a great many US Dexters.
The mechanics of A2 versus A1 milk producers is this: A CC cow will produce A2 milk that is completely free of A1 beta-caseins. An AA cow will produce a quantity of the A1 beta caseins in her milk. An AC cow will produce fewer A1 beta caseins in her milk than an AA cow. Probably half as many, but I haven’t been able to find where anyone has published figures for this.
The test tells us exactly what kind of milk the tested cow will produce. The test also tells us what kind of genes the CC bull will p-ass on to his progeny. A CC cow mated to a CC bull will produce all CC offspring from that paring. If either of the parents is AC, then the odds of a CC offspring drop to 50%. If both of the parents are AC, the odds of having a CC offspring drop to 25%. AA parents cannot produce any CC or AC offspring.
It is not possible to trace the A2 milk genes upward in the pedigree. A CC animal could have come from two AC parents. The only thing we can know is that neither of the parents was AA. One of the parents of an AC animal could have been an AA, but it’s just as likely that one of the parents was a CC.
All of the Dexters I had tested are fullblooded Dexters, registered with the American Dexter Cattle association. Some of them are dual registered with the Purebred Dexter Cattle Association of North America.
They are: Brenn of Paradise, ADCA 016376, CC, a black horned bull, born November 21, 2004. He is DNA parentage verified. His chondro test is pending.
Windridge Bantrybeth, ADCA 11327, CC, a black, horned cow, born June 9, 1996. DNA parentage verified.
Jam’s Leahtata, ADCA 018689, CC, a black, horned heifer, born May 10, 2005. DNA parentage verified.
Jam’s Lorelaidy, ADCA 018691, CC, a black, horned heifer, born June 2, 2005. DNA parentage verified.
Jam’s Irish Mist, ADCA 017922, AC, a dun, horned cow, born March 27, 2006. DNA parentage verified.
Sunrise Lizzie, ADCA 019164, AC, a black, horned heifer, born February 8, 2007.
I’ve lately found some things to read that hint that the A! Beta-caseins may have been around much longer than a hundred years. It was only the advent of artificial insemination that spread it around the world. Asian cattle (Bos Indicus) don’t have it. It doesn’t cross to them.
The United States Department of Agriculture is currently undertaking a project to map out nearly 5000 DNA markers in cattle. Currently, our DNA tests use no more than 20 markers. I’m contributing tail hairs from some of my cattle to the USDA project. Eventually, they will be able to decipher the cattle genetic code to the point that they can tell what breed it is. That will be great.
A lighter note: I picked Benn’s name from a list of Irish boy’s names. It means “Prince”. It’s also my mother-in-law’s name in a way. Her maiden name was B. Renn.
“Always leave ‘em laughing!” (Jimmy Durante)
Now I have a question. As written, "It doesn't cross to them." Asian cattle (Box Indicus) cannot carry an A1 gene. Do you really mean this? c.
c.
