Color Genetics help

bknthesdle · #1 03/19/14, 10:41 AM

We breed mostly Simmental or Sim-Angus cattle. We do have a couple of Hereford x Simm or Hereford x Angus cross heifers.

A couple of years ago, we had used a Hereford bull and kept back 3-4 of the baldy heifers he produced. Fast forward to last year. With those baldy heifers (two red baldies and two black baldies), we AI'd them to a calving ease BLACK Angus bull (TC Thunder 805) but we also covered our bases by turning them out with our homegrown red Simmental yearling bull.

1220 heifer (red baldy with some Hereford markings) produced an almost all black calf. So we assume the AI stuck with the Black Angus bull. BUT we thought her white markings would be dominant and yet all he had was a small white spot on his forehead and a small white spot around his navel. So is white NOT dominant?

1216 heifer (black baldy) produced a solid black calf. Once again we assume the AI worked to the black angus bull. Once again I expected a baldy baby and we got a solid baby.

1223 heifer (red baldy) produced a SOLID red calf. So...this means that the AI didn't stick and our red homegrown bull bred her and stuck? Also..once again no baldy calf when I was told white is dominant?

Then yesterday my last black baldy heifer calved. She had a solid red calf. This means that the AI didn't stick and she was bred by our red yearling bull?

So what kind of genetics are we looking at?

How can a red baldy heifer throw a black baldy calf? (does that mean she has both a black and red gene?) Is red dominant or is black?

And are all the red babies guaranteed out of my homegrown red yearling bull? (I tried looking up if TC Thunder 805 was homozygous for black but couldn't find out.)

And what about white? I expected all baldy babies from my baldy heifers and I didn't get a single baldy calf.

Would love some input!!! Hubby is stumped as I am. Everything he seemed to think he knew has been put to the test for this calving season.

Lurker_KS · #2 03/19/14, 12:04 PM

1220 Red baldy, is homozygous ee (red) and yes the Angus took so the calf is E^D e : black carrying red. Yes white Hereford markings are dominant, but since she isn't a full Hereford she probably isn't S^H S^h, but rather S^H S^+ meaning she only carries one copy of the gene causing white head markings and so that calf probably got the other S^+ gene from both sides and so is solid.

Same deal with 1216 and 1223, they are heterozygous (carrying two differnt genes) for white head, so they have a 50/50 chance of throwing a solid calf when bred to a solid colored bull. (S^H, S^+)

Yes the AI didn't take on 1223, so long as you are absolutely sure that the black Angus bull isn't carrying red (which he probably isn't, but it happens)

Yes you are right on the Black heifer, she is E^D, e, and when she was bred to your red bull the calf got the e from her and him, so ee (red)

A red cow will throw a black calf any time it is bred to a Homozygous E^D, E^D, black bull.

Any red calves should be out of your red bull, so long as the Angus is homozygous at the E locus, which he should be.

Black is dominant over red, White head markings dominant over not. But since it's dominant a black cow can be carrying red and you can't see it, and a white-headed cow can be carrying non-white headed, and you can't see it. Also although white-headed is dominant it varies in expression, so that calf with a small white spot might be showing it.

Can't figure out how to do superscripts, so the notation is a little sloppy.

~Tomboy~ · #3 03/19/14, 12:52 PM

This might also be of some help.

Genetics of color variation

http://www.piedmontese.org/Coat%20Color%20Cattle.pdf

Around page 46 might give an explanation.

Barb

agmantoo · #4 03/19/14, 01:28 PM

bknthesdle

Have you had any issues with the calves being rat tailed from the sim/angus crosses?

bknthesdle · #5 03/19/14, 04:41 PM

Can you explain a nondilutor bull? Does it mean that if he's breed to red they throw a red calf or breed to black he throws a black calf. Or just that he won't throw a gray or buckskin calf and that he could still throw a red calf on a black cow or a black calf on a red cow?

We have what is suppose to be a nondiluting red simmental bull out of two black parents.

bknthesdle · #6 03/19/14, 04:53 PM

Quote:

Originally Posted by agmantoo

bknthesdle

Have you had any issues with the calves being rat tailed from the sim/angus crosses?

Not that I've noticed in the last 4 years.

Lurker_KS · #7 03/19/14, 08:10 PM

A red bull can never throw a black calf from a red cow. For them both to be red they have to be homozygous ee at the E locus.

Page 43 of the document Tomboy posted covers the dilution gene in Simmental pretty well.

"A number of other breeds (Simmental, Gelbvieh, Scottish Highland, Texas Longhorn and others) carry a different dilution mutation, Ds, for Simmental dilution. This mutation is incompletely dominant to its wild-type allele, ds+. Thus, red animals heterozygous for Ds (i.e. e/e Ds/ds+) are light red and black animals (i.e.ED–Ds/ds+) exhibit varying intensities of grey colour. The Austra-lian breed, the Murrey Grey, appears to be homozygous for Ds acting upon a black background. Red (e/e) animals homozygous for Ds are light yellow and black (ED–) animals homozygous for Ds are light grey, similar to black cattle heterozygous for Dc. None of the breeds listed above carry Ds at a high fre-quency like that of Dc in Charolais. It seems likely that its frequency has decreased in the Simmental breed in the USA, as it is now desirable to have Simmental sires that will not produce dilute calves in crosses with black cows. On the other hand, the frequency of Ds in Gelbvieh cattle seems to have increased in the USA, due to the influence of certain popular sires"

Basically him being non-dilute means he doesn't carry it, so he won't throw a grey calf when bred to black.

randiliana · #8 03/19/14, 10:43 PM

Lurker_KS pretty much covered it all. The only other thing I would add, is that a non-diluter red bull would never throw either a tan or a grey calf, as long as he isn't bred to a cow that carries a dilution gene.

Here's another link that might help you. http://easygenes.blogspot.ca/

With a Simmental x Hereford there are quite a few different gene combination possibilities, depending on what your Simmentals are. Fleckveihs have spots and the solids may or may not carry that. Then you have the white face deal from both Simmental and Hereford. As well as your base colour of Red or Black.

opportunity · #9 03/26/14, 02:08 PM

1216 may not have been the black bull. With a black heifer you could get a black calf with the red bull. Did you turn them out right after AI or did you wait so you can just look at when they had the calvs?