Without launching into complicated genetics can someone tell me if one has a herd of short cows which are BDI-C would it be safe to use a short bull who is BDI-N. Or do short Dexters both need to be BDI-N for safe matings?
It appears that non-short bulls are also being tested for the elite scheme. I thought all non-short animals are BDI-N
Has anyone who has done this test found that they have short Dexters who are BDI-N? Or is the test mainly confirming what is already known and just sorting out the medium, are they short/are they not animals?
DNA testing
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Duncan MacIntyre
- Posts: 2372
- Joined: Tue Mar 30, 2004 12:38 am
- Location: Isle of Bute, Scotland, UK
If one parent is not a carrier then no bulldogs will result. For the most part it is possible to identify Dexters as long or short, these being non carriers and carriers respectively. But within each of these categories there is variation, and with shorter longs or longer shorts it can be difficult to tell. The genetic testing avoids any doubt, but remember that if one parent is a carrier then there is a 50% chance that any offspring will also be carriers, and if you are using "short" longs, ie non carriers, then it may well be necessary to test the offspring to know if they are carriers or not. The way to avoid having to test calves is to use two non carrier parents, then the offspring cannot carry the bulldog gene.
The reason non short bulls are being tested is because there must be no room for doubt. As soon as the test was available I had all my breeding stock tested unless I already knew they were carriers(because they had produced a bulldog in my year of hell, 1997) and last year I got rid of all the carriers from the herd. I am using a non carrier bull who was 40.5inches tall at 3yrs old in an inbreeding programme to bring down the size to what a traditional dexter should be, but without the bulldog gene. They have got far too big and heavy over the years. Some short legged Dexters today are much larger and taller than Kerry cattle were in the 1880's and 1890's.
Whilst it is true that using one non-carrier parent you are guaranteed not to get a bulldog you will never eliminate the gene that way - but it is a safe way to breed short legged dexters for showing.
Duncan
The reason non short bulls are being tested is because there must be no room for doubt. As soon as the test was available I had all my breeding stock tested unless I already knew they were carriers(because they had produced a bulldog in my year of hell, 1997) and last year I got rid of all the carriers from the herd. I am using a non carrier bull who was 40.5inches tall at 3yrs old in an inbreeding programme to bring down the size to what a traditional dexter should be, but without the bulldog gene. They have got far too big and heavy over the years. Some short legged Dexters today are much larger and taller than Kerry cattle were in the 1880's and 1890's.
Whilst it is true that using one non-carrier parent you are guaranteed not to get a bulldog you will never eliminate the gene that way - but it is a safe way to breed short legged dexters for showing.
Duncan
Duncan MacIntyre
Burnside Dexters 00316
Burnside
Ascog
Isle of Bute
Burnside Dexters 00316
Burnside
Ascog
Isle of Bute
Thanks Duncan, my animals never see the inside of a showring - too damned stressful all round - but I do like to see animals in my fields which are 'pleasing to the eye' as well as healthy and functional. At present I have a wide variety of Dexters and am taking this opportunity to sort out the herd.
I have three heifers which are short in stature, but non-carriers. One of them had a carrier mother.
One of our bulls looked non-short, but on testing, was shown to be a carrier of BD1. I have decided to keep using him on my non-carrier heifers because of all the other excellent attributes he has. The only bad thing about him is the fact that he carries a Chondrodysplasia gene. He did well in the few shows that he went to as a youngster. He has the ability to pass his beefy type on to his offspring. I'm also hoping he'll pass his mother's genes for a better udder, on to his daughters.
We can't wipe the genetic potential of a bull, just because he is a carrier. Breeding needs to be viewed as a long-term process of developing a herd. Starting with the cows you have and using the right type of bull to move the herd average towards the type of cows you'd like to have. That's why it takes a life-time.
Even if only 50% of his offspring are non-carriers, it'll be worth the cost of having to test all the long-legged looking heifers, to get the build that I'm looking for. The short-legged heifers won't be registered, but will make excellent meat, just like the steers. :D
I look at it this way. We have to breed a lot of bulls before we find one that looks good enough to breed from. The rest is called beef. :laugh: Hopefully it won't be as hard to get a good line of heifers.
One of our bulls looked non-short, but on testing, was shown to be a carrier of BD1. I have decided to keep using him on my non-carrier heifers because of all the other excellent attributes he has. The only bad thing about him is the fact that he carries a Chondrodysplasia gene. He did well in the few shows that he went to as a youngster. He has the ability to pass his beefy type on to his offspring. I'm also hoping he'll pass his mother's genes for a better udder, on to his daughters.
We can't wipe the genetic potential of a bull, just because he is a carrier. Breeding needs to be viewed as a long-term process of developing a herd. Starting with the cows you have and using the right type of bull to move the herd average towards the type of cows you'd like to have. That's why it takes a life-time.
Even if only 50% of his offspring are non-carriers, it'll be worth the cost of having to test all the long-legged looking heifers, to get the build that I'm looking for. The short-legged heifers won't be registered, but will make excellent meat, just like the steers. :D
I look at it this way. We have to breed a lot of bulls before we find one that looks good enough to breed from. The rest is called beef. :laugh: Hopefully it won't be as hard to get a good line of heifers.
Inger
NZ
NZ
Breeding is part science and part luck - I think it is just as difficult to breed a good heifer as it is a good bull. Like Duncan, I want to breed good deep cattle with short legs but from non-short parents and non carriers of chondrodysplasia.
The perfect animal has not been bred and I hope it never will be - we would end up narrowing the gene pool again!
As Inger shows, we each have different ways to achieve similar results "Vive la difference!"
Jo
The perfect animal has not been bred and I hope it never will be - we would end up narrowing the gene pool again!
As Inger shows, we each have different ways to achieve similar results "Vive la difference!"
Jo