Homo black bull on red cows......

[randiliana]

So why is it then when you cross a angus bull and a charolais cow, you get a lighter color calf even though the bull was a homozygous black?

The base coat color is always there. There are 3 base coat colors, Black, Red and Wild type (brownish). All other colors are the result of another gene MODIFYING the base coat color. Essentially a grey animal is a Black and a tan is a Red.

 

[Jeanne - Simme Valley]

So why is it then when you cross a angus bull and a charolais cow, you get a lighter color calf even though the bull was a homozygous black?

The base coat color is always there. There are 3 base coat colors, Black, Red and Wild type (brownish). All other colors are the result of another gene MODIFYING the base coat color. Essentially a grey animal is a Black and a tan is a Red.

Very well EXPLAINED. :clap:

 

[Jeanne - Simme Valley]

Thanks everyone. I was getting worried about finding some grey rat tail calves next year... :???: (have never had a rat tail calf before).

Now my next question, one black Gelbvieh I have is supposed to be homo and when bred to red she always has a black calf but this year her calf is a dark smokey grey..Now the calf is only a month old so she may still turn a dark black but if she doesn't does this mean she probably is not homo and does carry the red gene ?

Backtracking to this question.
Yes, it deffinately carries a red gene.
The black Gelbvieh cow will always give you a black factored calf (like Randi said - it could be grey/silver/chocolate - but it's black FACTORED).
"IF" you bred her to a red bull, all her calves are hetero black carrying a red gene (inherited a red gene from red bull). Both parents have to pass on one coat color gene. A red animal does not carry ANY black genes - only the two red genes. So therefore all calves out of 1 red parent will carry 1 red gene.
As far as the calf you have - dark smokey grey - may very well be true black as it gets older. Does the calf have black around it's eyes and a black switch on the tail? We get lots of calves this "chocolate" colored, but it they have the black hair around their eyes & tail switch - and usually black on bottom of legs - they turn out true black. BUT, they are "generally" heterozygous black. "Most" of the true blacks turn out to be homozygous black. But, we all know cattle don't like to go by the rules when it comes to "most of the time".
In your case, having a red sire, you are SURE the calf is heterozygous black (1 black 1 red gene)

 

[edrsimms]

Diluter gene

Thanks everyone. I was getting worried about finding some grey rat tail calves next year... :???: (have never had a rat tail calf before).

Now my next question, one black Gelbvieh I have is supposed to be homo and when bred to red she always has a black calf but this year her calf is a dark smokey grey..Now the calf is only a month old so she may still turn a dark black but if she doesn't does this mean she probably is not homo and does carry the red gene ?

 

[smoky]

As far as the Gelbvieh breed goes, the following applies. (I think it applies to most other solid colored black or red breeds of cattle as well).

If the cow or bull is black (homo or hetero) then they cannot and do not carry the diluter gene, as it is dominant over the non diluter gene and would cause the black to be gray.

So... the homo black bull will throw all black calves and some could dilute to gray if any of the cows have the diluter gene and express it. Even if the cow is diluter, that does not mean that she will definately have a gray calf. If the cow is hetero diluter her offspring will express it some of the time. A homo diluter cow will throw the diluter gene every time, which means the calf regardless of color will express the gene and show a lighter version of the "base" color. A blond calf is likely diluter and a dark red is likely not, but even a dark red one can have the diluter gene. I have a 14 year old medium red Gelbvieh cow that has had black calves, red calves, and gray calves. So I know that she is a hetero diluter. Her pedigree with some known red diluter ancestry backs this up.

To add even more to the conversation, the above assumes that the black is black and the red is red, with no white markings, as the spotting gene could even cause more variation to the calf crop.

A prime example of this is the homo black Gelbvieh bull Echo. Although he is homo black, he is notorius for white spotting his offspring. To attest to this, Almost every calf I ever had from him or one of sons or daughters had white navels, or white stars on the forehead, or white switches, or white stocking feet, etc.

My 2 cents.

Smoky

 

[Jeanne - Simme Valley]

Smokey - very well said.