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Posted: Mon Jul 05, 2004 3:49 pm
by strawberriesclint
Can anyone tell me does it matter crossing a red bull with a black cow and if the calf comes out black with a red tint can you still show these. As you can tell by my many questions I am very much a novice. cyndy
Posted: Tue Jul 06, 2004 12:03 am
by Duncan MacIntyre
The result of crossing a red and a black depends on the genetic make up of the black. Red is a recessive - it only shows in animals which have inherited a red gene from each parent - so a red Dexter has two red genes. A black may have two black genes, or it may have one black and one red - the red will not show. I do not think the tinge we see on a lot of cattle is much indication of genes carried.
The statistical implications of crossing are quite predictable - given that each gene of each parent may combine with each from the other parent there are four possibilities. If you cross a red/red with a black/black, you can ony get red/black - these will all show as black. If you cross a red/red with a black/red, you may get red/black (2 of 4) or red/red (2 0f 4) - ie 50% red and 50% black. If you cross two blacks which are both carrying red, ie red/black and red/black, you will get 25% red, 50% black but carrying red, and 25% black/black. If you cross a red/red/ with a black/black, all offspring will be red/black, so will show black but carry red.
This is probably best shown in diagram formrather than in text, sorry if it seems complicated, but it really isn't.
I think most of the red tinge on black cattel is the result of nutrition and sunlight and age of hair - most which tend to be a bit red about the edges look a lot blacker when the new coat comes in in the spring, and when feeding is at its best. This is not to be confused with non black coat colour such as brindle of course. Perhaps some judges would care to give us their wisdom of how they cope with this in the show ring.
Duncan
Posted: Sat Jul 31, 2004 6:09 pm
by Liz
Duncan you say that most of the red tinge on black cattle is the result of nutrition and sunlight and age of hair. I'm a novice and have one steer which has a reddish tint all year round. I thought it might be copper deficiency and put out licks, but nothing seems to have changed. He eats the same stuff as the rest of the herd. Is this likely to be a sign of something wrong, or just one of those things?
Posted: Sat Jul 31, 2004 7:05 pm
by Duncan MacIntyre
Liz wrote:Duncan you say that most of the red tinge on black cattle is the result of nutrition and sunlight and age of hair. I'm a novice and have one steer which has a reddish tint all year round. I thought it might be copper deficiency and put out licks, but nothing seems to have changed. He eats the same stuff as the rest of the herd. Is this likely to be a sign of something wrong, or just one of those things?
I would think it is just one of those things. There may of course be an explanation genetically but very difficult to be sure we understand all the factors. Morna Arkle, sadly no longer with us, used to say that there were 5 colours of black in dexters and I think she may well have been right. I think there is little doubt that all red dexters are not red because of the same genes.
I certainly don't think it is likely to be anythhing wrong.
Duncan
Posted: Sat Jul 31, 2004 11:40 pm
by Marg Rawlings
Well I will jump in and disagree. In our herd I have certainly found that the red/black gene carries have a reddish tinge to their coats. This is confirmed when I can put two of these red/black carries together and produce a red calf. It has just been an indicator here. The coat colouring of these animals does not seem to change no matter what the feed or weather conditions.
Sorry if I have confused you all even further.
Have a great day
Marg Rawlings :D
Posted: Sun Aug 01, 2004 10:31 am
by Duncan MacIntyre
In reply to Marg, I would have to say that I do not entirely disagree with what she says. But I am not totally convinced that either all those with red tinge are red carriers or that all red carriers have a red tinge. At the moment in the Burnside herd we have several calves which could be carrying Dun which have a bit of a dun tinge to them, but I also have a cow sired by Apple Joe and as far as I know is very unlikely to carry dun. What we really need is some good research now that the colour genes readily identifiable.
Duncan
Posted: Sun Aug 01, 2004 10:32 am
by Sylvia
Brindle is bad I understand so where does that come from?
Posted: Sun Aug 01, 2004 5:40 pm
by Duncan MacIntyre
Brindle is present in quite a number of breeds but not sought after in very many. There are quite a number of brindle Highland catttle though there will have been little input from them to Dexters. I think that there may be brindle genes in some Jerseys but might not be correct there. They would certainly have some chance of influencing Dexters through grading up. Another variation of colour we see from time to time in Dexters is black with a red dorsal stripe, and this is also recorded in Jerseys but I do not know if it is exclusive to them. Various other breeds may also have had an influence. But many colours may have been present in Dexters since before the herd book was formed and not be well recorded, or not even much noticed because of their recessive nature. So I am always a bit sceptical about labelling anything as not belonging. Going back to the brindle, I have seen some Dexters which at first glance were very reasonable blacks, but when looked at in different lights you could see an underlying brindle pattern though very very dark. Noticing things like that certainly makes an inspector who has rejected brindle animals as not conforming to the breed standard think a bit!!
Duncan
Posted: Mon Aug 02, 2004 12:41 am
by Marg Rawlings
For us I can relate the brindle colour back to cattle from a Jersey base, and it was more prolific if you used a bull that was red factoring. Many of the calves are born red and them develop the stripe pattern some months later. I am reluctant now to use Jersey as this problem can also come out 1 or 2 generations later.
Duncan I have one of those cows who is dominantly black, but when you stand back she has the definite brindle stripe running through her coat, her mother was brindle. Obviously I have not registered her, but on a positive note all of her daughters have been solid black with no apparent striping. Last year I did use a red bull on her to see what would happen and got a brindle steer.
Hope our experiences have been useful.
Marg Rawlings :;):
Posted: Mon Aug 02, 2004 1:21 am
by Kathleen
Just want to clear up a 'misconception' here (one that has been around for some time and one that I actually discussed with Jane Paynter who I understand was the first Dexter breeder to make these 'Jersey's carry brindle' statements) ...PURE Jersey do NOT carry brindle... by carry I mean that if the gene is there then you would see a brindle animal and if you have a 'brindle jersey' then you do NOT have a PURE Jersey.
The great problem with all these types of discussions is that some people label animals as -such and such- breed and meanwhile they are of mixed ancestry and simply look like -such and such- breed more than another part of their ancestry.
I would agree that 'unless you know what you are doing' do not use Jerseys to try and breed RED Dexters because the Brindle gene which is carried by Dexters will show up almost every time...but just for the record this could also be said for some other breeds of cattle as well as Jerseys.
Duncan re the 'red dorsal strip' ... yes it is _in my oppinion_ a factor which seems to come from Jersey in the breeding.
Before I leave the subject I would like all to understand that my statements about 'Brindleing' and/or 'Jerseys' are backed up by scientific opinion... which are a result of test breedings ...which are expressed in modern genetics books... and 'just for the record' those same books state that Angus cattle carry the Brindle gene at a very high frequency!
...So it might be concluded that the brindle gene in Dexter comes from all the Angus used in it years ago ...BUT that would not be a conclussion based on any sound evidence because you would have to establish that Dexters did not already have brindeling before the introduction of genetics from the Angus (or any other) breed.
RE different coloured 'reds' ... there are 2 genetic types of red in the Dexter breed... in all red breeds there are other genes which can affect the coat colour which means you can end up with some big 'differences' in the colouration of one red animal to another... what you would 'consider' to be 'correct' in Dexters is entirely up to you ... and once again it would be nigh impossible to try and say (given the history of the breed) that any one in particular IS the correct one.
Regards
Kathleen.
Posted: Wed Aug 04, 2004 5:33 pm
by Carol K
Kathleen,
since upgrading/purity cropped up, you mentioned Andrew Sheppey in one of your previous post and I wondered if maybe you could fill me in on the study(?) that he did. I don't mean to hijack this thread, but reading it jogged my memory on it, maybe a new thread? Would love to hear what he discovered.
Many Thanks
Carol K
Posted: Thu Aug 05, 2004 12:40 am
by Kathleen
Hi Carol,
No worries
Kathleen