Color Genetics

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kanshow

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I need help figuring this out.  I'm a little sleep deprived and punchy - calving heifers is my excuse. 

If a bull is homozygous black, that means they do not carry a red gene, but can they still carry a diluter type gene?

Here is the situation.    We have a gray cow that was supposedly bred to a homozygous black bull.    We got a gray calf.    Can this happen?  The breeding fits with the AI date perfect and any bull she would have been exposed to later would also be homozygous black. 

 

JSchroeder

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Assuming you are talking about the Charolais diluter gene, yes, it was a 50/50 shot the cow would pass on the gene.  You only need one copy of that to make a grey calf.
 

frostback

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The actaully colour of a bovine is only 2 genes. One from the sire and one from the dam, but yes there are numourous others they carry. Face white, spotting, socks, body white, diluter, etc. so yes your gray cow had a 50/50 chance of having a gray calf. Your gray cow is hetro black and the red she carries has a tag a long diluter. Frostie
 

DL

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kanshow said:
I need help figuring this out.   I'm a little sleep deprived and punchy - calving heifers is my excuse.   

If a bull is homozygous black, that means they do not carry a red gene, but can they still carry a diluter type gene?

Here is the situation.     We have a gray cow that was supposedly bred to a homozygous black bull.    We got a gray calf.    Can this happen?   The breeding fits with the AI date perfect and any bull she would have been exposed to later would also be homozygous black. 

Check out this web site http://homepage.usask.ca/~schmutz/colors.html
 

kanshow

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Thanks!  The cow is out of a red simmi cow who obviously carries the dilute.
 

Jill

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Ok, I'm lost, so breeding to a homozygous black bull doesn't mean they will always have a black calf, I thought that is what HOMOZYGOUS meant?
 

frostback

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Jill said:
Ok, I'm lost, so breeding to a homozygous black bull doesn't mean they will always have a black calf, I thought that is what HOMOZYGOUS meant?

Homozygous means more that a animal only has one of the same gene to give more than they will only have a black calf. When you breed a Angus to a Char you get a smoke every time. Shades will vary. In this case it was a 50/50. The diluter gene is also dominant meaning that is has to been expressed or seen to be there, unlike a recessive that can be there but hidden. Like the spotting.
 

kanshow

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So in this case, Homozygous black just means that I will not get red?    If I were to take this same gray cow and breed her to a non-diluter red bull, what are my chances of getting gray or black?   

Here is another odd thing we have going on this year.    We are getting some white faces from the same AI sire this year - on all the bull calves and only the bull calves - including the above mentioned gray calf.    The heifers have been all solid black to date. 
 

frostback

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So in the calf you had you had a 50/50 chance at a solid black and the gray you got.
If you breed this cow to a red bull next year you have a 50/50 chance at a hetro black and a red smoke calf(you cannot figure the shade of red, orange, yellow)it may be a yellow to a pretty dark red.
As far as only the bulls being white faced, it is a flip of the coin, and what is on the cows side.
 

DL

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Jill said:
Ok, I'm lost, so breeding to a homozygous black bull doesn't mean they will always have a black calf, I thought that is what HOMOZYGOUS meant?

Jill - check out the above web site - there are multiple genes that are involved with color and pattern - so homozygous means that they pass a copy of that gene to their calf (ie black) and in this case the black gene is modified by the diluter gene - make sense? sort of?
 

VJ

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My brother sold his good Simmy bull and bought an Angus bull to breed his black and a few brown Simmy cows in hopes of eliminating brown calves.. The next spring about half of the calves were still brownish-gray.
 
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