Inbreeding? - What are ther rules and risks?

[Inger]

Haven't you heard that exercise is dangerous to your health Duncan. :laugh: Glad your leg is better now, we've missed your postings.

JamsHundred, the fact that the colour Black is dominant over the other two colours is the reason why very few Reds have turned up in the States. Without a Bull carrying a Red or Dun gene, you'll always get Black calves. You need the recessive colour gene in both parents, before it can show up in a calf.

[Kirk- Cascade Herd US]

Three herds that have been closed for decades have not bred reds of which I am familiar. Woodmagic has dun in their herd, but no reds, Davis herd in the US has black, and no reds, (large herd closed since the 60's), and the Bedford herd in the US has only black animals. There are likely other examples. These three herds linebreed and still no red animals.

Here are the most likely explanations for the three closed and inbred herds with no reds:

1. The closed herds started with only homozygously black animals (with or without the dun factor).

2. The closed herds did start with an animal that carried a single recessive red gene, but the gene was lost early in the game (perhaps the one or two carriers were sold, slaughtered, or castrated before passing the gene on to others in the herd).

3. A single red gene still exists in one or two cows in the closed herd, but a bull has not yet been selected for breeding that also carries red.

Under options 1 and 2, the closed herds will never have a red calf. Under option 3, as was mentioned earlier, the probability of a red calf is pretty low in a mostly homozygously black herd (with or without dun), but with DNA testing helping you to locate that single red gene and using inbreeding, you could greatly increase the probability of getting a red calf in just 3 or 4 years.

[Inger]

I've tried breeding Red calves using Black cows carrying Red and a bull carrying Red. So far I've only had one Brindle Red bull which was steered and one Red heifer. So if its that hard to get Red calves out Red carriers, I'm not surprised it much harder in a herd that only has the odd animal which carries Red.

Murphy's Law dictates that after we sold the mother of our Red heifer, she gave birth to another Red heifer calf for the new owners. :laugh: Its a full sister to our heifer. This year I am pushing fate and have leased a Red Dexter bull. So now I have to get a Red calf from this Red heifer of ours. Roll on October/November. I hope it isn't a bull calf ! As it will only be a Grade 4 and we can register bulls unless they are Grade 5 and higher.

[Broomcroft]

Hello

This topic is way over my head, but can I ask a question?

I have a pedigree herd of 90 or so dexters with a pure red dexter bull, purchased from the Moonshine herd. I've had 20 calves by this bull in the last few months, and 9 out of 10 males are black, and 9 out of 10 females are red.

Is that what I can expect or is it just statistics at work and eventually it'll even out? My cows are a mixture, largely black.

Clive

[Duncan MacIntyre]

Very interesting results, but there is no connection between colour and sex in cattle. What will be statistically true over a large number is that red to red matings will give 100% red calves, red to black carrying red will give 50% red, and red to black not carrying red will be 100% black. But all the black calves from the red bull will carry red.

Duncan

[groubearfarm]

Then of course there is a dun . . . . .

[Duncan MacIntyre]

Which dun? The old dun cow??

Dun can

[Inger]

There's that wit again Duncan. :D

Broomcroft, it was just coincidence that gave you those figures. If you try the same matings again, you'd probably get a different result.

We've got 4 cows/heifers that may or may not carry Red, that have been run with a Red bull this year. I'll let you know in November what our Stats are regarding colour versus sex of the resulting calves. We also ran a Red heifer with the same bull , so I can tell you now that she'll have a Red calf. This Red bull also carries Dun, so I ran a cow that may or mayt not carry Dun also, just to see what happens. She has Dun on her Father's side - two generations ago. But she also has Red on her Dam's side two generations ago. Time will tell what colour calf I get. I just hope its a heifer.

[Broomcroft]

Had 2 new calves this morning within minutes of each other, one male black and one female black, so the stats are coming into line as you predicted.

What an amazing run of red females and black males though. I'm not a gambler, but I would imagine the chances of such a run when the odds are 50/50 or less, are remote in the extreme.

Clive

[Inger]

So you're out to buy a Loto ticket then? :laugh:

[Broomcroft]

Inger

I wasn't going to buy a Lotto ticket but I am now...just had another black male.

Looking through my records, I have cows that only produce black males and cows that only produce red females, never the other way around, even after 5 calves.

Clive

[Broomcroft]

And another one this morning!

Clive

[Inger]

Looks like your herd have finally got the colour thing sorted then Clive. They've found out the colours can come in different sexes. :D

[wagra dexters]

They must have been GM'd with autosex chickens.