? bout free martin?

[ANAZAZI]

If a heifer is twin to a bull, and is still fertile, she is no freemartin. She is just a twin. And her calf has a mother and a father.

 

[cow pollinater]

An interesting(at least to me) aside... If you ever do get one that carries a calf to term, and some do but it's a fraction of a percent, the resulting calf would geneticly have two fathers and no mother.
Now you know why I can't remember names or birthdays.

I am not sure if I understand what you are saying here. A freemartin heifer is just like a regular heifer genetically, but her repro tract was not developed due to the testosterone from the bull calf forming (so environmental cause, not genetics). She has a sire and a dam. In the very unusual case when you get one that does have a fully functional repro tract, and she can have a calf, that calf is dammed by her and sired by the bull, so genetically has a sire and a dam.
So why am I having a hard time understanding the resulting calf would have two fathers and no mothers? I usually follow your thinking CP, but having a hard time here with this one, and I know you have a ton of experience in this.

And speaking of freemartin females that can have a calf, has anyone figured out WHY it happens? I know why the repro tract does not form, so what prevents the testosterone from the male twin from crossing over the placental membrane in the very few cases of fertile freemartin heifers?

FM's are a result of an embryo split. That's why the FM has male charachteristics, she's the junk half of a male embryo. The level of development is a clue as to where the split happened during pregnancy as the more male she is the later the split as males take more development than females. If you do get one (exceptionally rare) that is developed as a female enough to carry a calf to term she is still a male as she is a split from a male embryo. Hence the resulting calf has two sires and no dam.

 

[Muddy]

I thought freemartins are fraternal twins?

 

[Katie]

It is my understanding that in order to be a embryo split they would be identical twins which would mean same sex. From my research Freemartins have to be the result of 2 separate embryos that's placental membranes end up joining/sharing around day 40. I would figure that would explain why some freemartins are effected more than others possibly they shared more of the placenta than ones that aren't as affected. The exchange of blood, antigens, and hormones...mainly hormones from the male is what causes the heifers repro to either be underdeveloped and/or contain elements of a bulls reproductive tract. A freemartin is however genetically female.

 

[dun]

It is my understanding that in order to be a embryo split they would be identical twins which would mean same sex. From my research Freemartins have to be the result of 2 separate embryos that's placental membranes end up joining/sharing around day 40. I would figure that would explain why some freemartins are effected more than others possibly they shared more of the placenta than ones that aren't as affected. The exchange of blood, antigens, and hormones...mainly hormones from the male is what causes the heifers repro to either be underdeveloped and/or contain elements of a bulls reproductive tract. A freemartin is however genetically female.

Correct!

 

[cow pollinater]

It is my understanding that in order to be a embryo split they would be identical twins which would mean same sex. From my research Freemartins have to be the result of 2 separate embryos that's placental membranes end up joining/sharing around day 40. I would figure that would explain why some freemartins are effected more than others possibly they shared more of the placenta than ones that aren't as affected. The exchange of blood, antigens, and hormones...mainly hormones from the male is what causes the heifers repro to either be underdeveloped and/or contain elements of a bulls reproductive tract. A freemartin is however genetically female.

Correct!

My understanding of it came from the university of Illinios as part of a online diary reproduction class I was involved in around ten years ago. I won't argue that I'm right or wrong but the freemartin part was one of only a handful of subjects that I remember well.

 

[inyati13]

I am not following CP's logic on the dam and sire. Forgive me. It may be my mistake because I don't look at the issue in the same way as he does. I see it as a genetic deformity in the same context as millions of other aberrations. Most occur during the splitting of chromosome pairs, meiosis, embryonic development, etc. In the case of a Free-Martin, this aberration is unique as it occurs in utero.

From the Principles of Genetics, put into my own words for this response:

A "free-martin" is a result of an aberration where a mammal originates as a female (XX), but acquires the male (XY) component in utero by exchange of some cellular material from a male twin, via vascular connections between placentas. Externally, the animal appears female, but various aspects of female reproductive development are altered due to acquisition of anti-Müllerian hormone from the male twin.

Fire Sweep: testosterone plays a role a little later.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

Fire Sweep: I also have a little beef with you. I do follow you that it is "environmental" in the context that it occurs in the uterine environment. It is the contamination of the heifer's genotype by the bull twin's XY that causes the aberration. When is that not genetics? I would rather you say it is genetic. If not would we then have to say that aberrations of the genotype that occur during meiosis are not genetic because they occur in the environment of the gonad?

Furthermore, in response to why some free-martins may calf. Remember, the biological realm is not guided by divine order as you think. Shyt happens to biological units. In some cases, highly aberrant units succeed in reproduction, albeit, the offspring are fouled up.

 

[Fire Sweep Ranch]

Here is a definition that, I think, is easier to follow that Inyeti's description: "When a cow is pregnant with two fetuses, the extraembryonic membranes of each fetus frequently fuse forming a common chorion[1]. Thus, both the male and female fetus share the same cotyledons. Cotyledons, which are distributed across the surface of the chorion, consist of many blood vessels and connective tissue. By sharing the same cotyledons, both the male and female fetus share the same blood supply. This blood provides both the male and female twins with the same hormonal combination (including testosterone and anti-müllerian hormone). The fusion of the membranes generally occurs within 1 month of gestation, right before sexual differentiation of the fetus takes place. Since the sexual differentiation of the testes occurs before the ovaries (recognizable at around 40 days), the hormones produced by the testes work to inhibit the reproductive growth in the female fetus. The hormone that has this negative effect is anti-müllerian hormone[2] which stops the growth of the paramesonephric ducts[3] in the female fetus. Thus, the female heifer, now known as a freemartin, has an incomplete development of the reproductive tract. This includes the ovaries which are underdeveloped and are incapable of producing hormones such as estrogen, greatly reducing the femininity of this heifer." The [3] goes on to develop into the ovaries, Fallopian tubes, and uterus.
I argue that it is Environmental, because it happens due to the environment; if the male twin was not there, she would have formed normally. If it was genetic, it would come as a result of genetic flaw, regardless of a male twin or not. The gonad is a entirely different story!
She can blame it on her brother!
That still does not explain why some male/female twins are fertile. I do not want your speculation on God, and in science, "shyt" does not "happen", as you said! There is a scientific explanation...

 

[inyati13]

Here is a definition that, I think, is easier to follow that Inyeti's description: "When a cow is pregnant with two fetuses, the extraembryonic membranes of each fetus frequently fuse forming a common chorion[1]. Thus, both the male and female fetus share the same cotyledons. Cotyledons, which are distributed across the surface of the chorion, consist of many blood vessels and connective tissue. By sharing the same cotyledons, both the male and female fetus share the same blood supply. This blood provides both the male and female twins with the same hormonal combination (including testosterone and anti-müllerian hormone). The fusion of the membranes generally occurs within 1 month of gestation, right before sexual differentiation of the fetus takes place. Since the sexual differentiation of the testes occurs before the ovaries (recognizable at around 40 days), the hormones produced by the testes work to inhibit the reproductive growth in the female fetus. The hormone that has this negative effect is anti-müllerian hormone[2] which stops the growth of the paramesonephric ducts[3] in the female fetus. Thus, the female heifer, now known as a freemartin, has an incomplete development of the reproductive tract. This includes the ovaries which are underdeveloped and are incapable of producing hormones such as estrogen, greatly reducing the femininity of this heifer." The [3] goes on to develop into the ovaries, Fallopian tubes, and uterus.
I argue that it is Environmental, because it happens due to the environment; if the male twin was not there, she would have formed normally. If it was genetic, it would come as a result of genetic flaw, regardless of a male twin or not. The gonad is a entirely different story!
She can blame it on her brother!
That still does not explain why some male/female twins are fertile. I do not want your speculation on God, and in science, "shyt" does not "happen", as you said! There is a scientific explanation...

Kris. I disagree with you on the environment. The free-martin has a flawed genotype. That is genetics!!! However, the important point is understanding the details. Yes, the world is best approached on the basis of a natural explanation. My point on the "shyt happens" is better stated as follows: The natural world is not perfect. I can point to my sinus problem as an example. They are poorly designed. Auto-immune responses are another example. The natural world is wrought with flaws. Free-martins are a flaw of nature. I agree with you on leaving our philosophical differences out of it.

 

[cow pollinater]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

 

[inyati13]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

CP, I saw a study this morning about that but did not have time to study it. I will look again this afternoon.

BTW: Kris, are you blaming the twin bull calf? Poor Glenn. I bet you blame him whenever one of the kids makes a mis-step! Has to be the Sires fault, right?

 

[Katie]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

Correct me if I'm wrong but if she was able to
Have a calf wouldn't she be like any other heifer and not hot have the Y chromosome? After all isn't that what they are testing for in the Freemartin test?

 

[branguscowgirl]

Here is a definition that, I think, is easier to follow that Inyeti's description: "When a cow is pregnant with two fetuses, the extraembryonic membranes of each fetus frequently fuse forming a common chorion[1]. Thus, both the male and female fetus share the same cotyledons. Cotyledons, which are distributed across the surface of the chorion, consist of many blood vessels and connective tissue. By sharing the same cotyledons, both the male and female fetus share the same blood supply. This blood provides both the male and female twins with the same hormonal combination (including testosterone and anti-müllerian hormone). The fusion of the membranes generally occurs within 1 month of gestation, right before sexual differentiation of the fetus takes place. Since the sexual differentiation of the testes occurs before the ovaries (recognizable at around 40 days), the hormones produced by the testes work to inhibit the reproductive growth in the female fetus. The hormone that has this negative effect is anti-müllerian hormone[2] which stops the growth of the paramesonephric ducts[3] in the female fetus. Thus, the female heifer, now known as a freemartin, has an incomplete development of the reproductive tract. This includes the ovaries which are underdeveloped and are incapable of producing hormones such as estrogen, greatly reducing the femininity of this heifer." The [3] goes on to develop into the ovaries, Fallopian tubes, and uterus.
I argue that it is Environmental, because it happens due to the environment; if the male twin was not there, she would have formed normally. If it was genetic, it would come as a result of genetic flaw, regardless of a male twin or not. The gonad is a entirely different story!
She can blame it on her brother!
That still does not explain why some male/female twins are fertile. I do not want your speculation on God, and in science, "shyt" does not "happen", as you said! There is a scientific explanation...

Excellent definition Kris! Very well said. Thank you.

 

[inyati13]

Fire Sweep, IMO, there is one important omission to your explanation of the concept of a "free-martin". That omission is that a free-martin is a Chimeric. In genetics, that means an organism which is composed of distinctly different cells. If you read some of the more detailed studies of freemartin heifers you will find that there are degrees of blood chimaerism (60, XX/XY) that occurs. There are free floating cells in an otherwise XX female mammal. I realize that your explanation may not have been intended to be comprehensive but it gives the appearance that the freemartin is solely the result of the "uterine environment" and the effect of anti-Müllerian hormone from the male twin. That is accurate but the characteristic of their "chimeric" state which is the addition of the acquired male sex chromosomes XY and the resultant chimeric state (60, XX/XY) is important from a genetic point. I have found an excellent research paper that you might want to read. It is PDF and protected from copy so I cannot provide it here. I can try to send it to you by e-mail or if someone can instruct me on how to post a PDF here, I would be happy to do so. This is why I noted it as a genetic disorder but that is not important. What is important is noting that the genetic aberration exists. In hindsight, it is more appropriately in the realm of Teratolgy: the study of abnormalities of physiological development.

Kris: the reference is as follows:
Freemartinism in Cattle
ISBN: 978-1-62081-064-4
Coptright 2012 Nova Science Publishers, Inc.

 

[inyati13]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

Correct me if I'm wrong but if she was able to
Have a calf wouldn't she be like any other heifer and not hot have the Y chromosome? After all isn't that what they are testing for in the Freemartin test?

Katie: on a practical basis, a freemartin is sterile. That is why neither Fire Sweep nor I was following CP's logic. The genetic state of a freemartin heifer is XX - normal female mammal but they also exhibit chimerism which means there will be cells that exhibit the XX/XY compliment. There are 60 chromosomes in a cow. The chimeric state of a freemartin heifer is noted as (60, XX/XY). That is what they test for to diagnose a freemartin.

 

[inyati13]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

CP: exceptions exist to everything but freemartins are sterile from all I can find in my research.

 

[Katie]

Katie: on a practical basis, a freemartin is sterile. That is why neither Fire Sweep nor I was following CP's logic. The genetic state of a freemartin heifer is XX - normal female mammal but they also exhibit chimerism which means there will be cells that exhibit the XX/XY compliment. There are 60 chromosomes in a cow. The chimeric state of a freemartin heifer is noted as (60, XX/XY). That is what they test for to diagnose a freemartin.[/quote]


Thank you for the explanation that makes more sense to me. I wasn't able to follow CP's logic either but I really don't have any first had experience with a Freemartin just what I have read.

 

[Nesikep]

I had a heifer that was twin to a bull about 3 years ago, she was raised by a different cow, and that cow did a great job of it.. She was one of the nicest heifers of the year, but I wasn't going to take a chance on her. She looked pretty normal in her lady parts, so there's a chance she was OK.

 

[cow pollinater]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

CP: exceptions exist to everything but freemartins are sterile from all I can find in my research.

Enough are that you could make the blanket statement and say that they all are and be right. The ones that are capable of carrying a calf to term are a fraction of a percent and even if they do they have to do it in front of someone that's paying attention for it to be documented. Otherwise it's just a heifer that didn't breed up.
I'm swamped with farm work right now but if I get a rainy day I'll do some homework and share. I'm pretty sure I'm on the mark from the information I was given at the time.

 

[inyati13]

.

I disagree with CP on the idea of "no dam". Afterall, it occurs in utero in the dam. One of each of those pairs of sex chromosomes is contributed by the dam. Where is the logic, that the dam is not part of the equation? The genotype of a Free-Martin would be abnormal in that it would be XXXY on the sex chromosome. I will assume that CP is rhetorical in saying there is no role played by the dam. His explanation IMO could lead to confusion and mis-understanding.

I'm not talking about the freemartin herself but her offspring if she is able to carry a calf to term.

CP, I saw a study this morning about that but did not have time to study it. I will look again this afternoon.

BTW: Kris, are you blaming the twin bull calf? Poor Glenn. I bet you blame him whenever one of the kids makes a mis-step! Has to be the Sires fault, right?

I apologize for the statement highlighted in bold. It was meant in harmless fun. I have the highest regard for Fire Sweep and her family. It is a stupid comment that I regret not spending a moment thinking about.