Help! Need info on bull

[Inger]

Yes Sylvia, you're right. There is no such thing as an animal that suits all people. Every breeder has slightly different criteria that they are aiming for in their 'perfect' cow or bull. For me, its an animal that will thrive on poor pasture, calve easily and feed that calf well. I need the calves to be fairly worm resistant, as we only drench them at weaning and the cows are only medicated individually as and when they require it. We need our animals to have good feet, because of the steep hills they're required to graze. I'd like a polled herd, for ease of maintainence and it would be nice if they all looked good in type and had good temperaments as well.

Other breeders would obviously have different priorities. So of course would be aiming for a slightly different animal. I'm sure though, that the Dexter as a breed can be adapted to suit most situations. As Woodmagic says, its very satisfying when you can see that you are beginning to achieve your goal. :D

By the way Sylvia, the weatherman says we can expect a cold front to pass over NZ during New Year's celebrations. Some parts of the South Island can even expect snow. I'd just be glad to get rain to keep the grass growing, so it doesn't dry out too much. January and February can be very hot and dry in some parts of NZ. I'm hoping that it won't be too dry this year as we have recently sown grass (in our Spring) which would prefer another year before being challenged by lack of rain. Here's hoping. All the best for your Winter this coming year.

[JamsHundred]

Re: Cardiff research

As you know Ms. Rutherford, the US has in recent months submitted samples to the UK for inclusion in the Cardiff research.

Your comment in the above thread raises this thought and question:

The Woodmagic herd has been closed for half a century.
The English herd has had considerable introgression via the appendix and experimental registries. Is the Woodmagic herd and the UK Dexter herd in general, basically the same genetically? If so, then would one conclude that introgressed genetics in a breed makes absolutely no change?

The US herd has never permitted introgression, so the US herd, on paper, has had no introgressed genetics. There is one bull imported in 1965 that has been rumored to have introgressed genetics, and his semen has also been sent to the UK for research but that is the only questionable animal pre 1980's imported here. The only other genetics beside US animals are the Woodmagic animals imported into Canada, and later into the US herd. It is varied samples from these US herd animals that have been sent to the UK. Thus, the animals sent from the US, by pedigree, have absolutely no introgressed genetics.

This should make for a very interesting overview of the individual animals as well as an interesting comparison of the various animals by country of origin, ( and perhaps herds, since there are animals from two herds closed for over 40 years- one US one UK), as to the effect, or lack there of, regarding introgressed genetics. It will also be interesting to see if there are genetic differences between the two closed herds, both of which have bred away from the dwarf genetics to non-carrier animals, with the only exception being one herd has had only black animals, and the other includes dun.

If I were younger, and brighter, I think I'd be drawn to the study of genetics.

[Inger]

Don't let age stop you Jamshundred and lack of brains never stopped me, I just had to work harder at it. Lifelong learning keeps your brain stimulated. It good for mental health. So go for it, its never too late to learn new things. :D

[JamsHundred]

I must say, Inger, " You are absolutely correct", and as I am not one to allow "little" things to block my way for very long, I decided it was past time for the old dog to attempt a new trick. I gathered an ice-cold Coke, a clean notebook, pen, and my barely thumbed copy of " The Genetics of Cattle", settled into my easy chair, searched the index for the chapter on color genetics, slipped my reading glasses on, and thus I began my mission.

I read the introductory pages and then came to the first sub-heading of the chapter, titled " The Basis of Pigmentation in Cattle", and I read the first lines of the first paragraph, as follows:

" The basis of coat colour in cattle and all mammals is the presence or absence of melanins in the hair, ( Searle, 1968)."

Well, I must say, that is simple enough. I continue . . . . .

"The melanin is found in the malanosomes of the cytoplasm of the malanocytes. These melanosomes are transferred to the hair as it grows through a process of exocytosis."

Yikes, and good golly Miss Molly! Is this any way to start a New Year? Who said that about old dogs and new tricks? As Scarlett said to Rhett, " I'll think about it tomorrow!". For sure this is going to put me to sleep.

[Inger]

Good on you for trying JamsHundred. :D I've found that the easiest way to learn and remember something technical, is to translate it into my own words and write it down. As long as you can grasp the concept, the jargon words don't matter. After all, its the principle of the idea that is the most important thing. The scientific words are just labels.

If relabeling a biological process or name helps you to remember what's going on, then that's fine. After all, you're not sitting an exam, so the exact words don't matter. :;):

[Woodmagic]

Well said Inger, you are absolutely right, the glossary in genetics is frightening, but the principles are pretty simple. I am certainly no expert, but when I set out a very long time ago, I took exactly the path you suggest, and wondered why the geneticist had to make it all sound so complicated. I find it fascinating, and not just in connection with my beloved Dexters.
As for the progress on the Cardiff research, the Woodmagic herd does differ from the mainstream, as Professor Bruford said at the AGM. With the limited lines in use and the length of time the inbreeding has been practised, I would have been surprised if it didn’t. I shall find the results on the comparisons very interesting. One of the aims of the exercise is to find a method, which enables introgression to be identified. It has to be remembered that genuine breeders can be fooled. However, I was cheered that the results to date do not suggest that the British Dexter has suffered to the extent that some folks had suggested.

[Inger]

Perhaps the Dexter genes are just too strong to be overpowered by the other breeds, or is it that they share common ancestors and thus genetic similarities. When is the report due to be completed? I'd be very interested in the findings.

Genetics facinate me too. It seems to go according to some basic rules, but then an individual animal will turn up, that breaks the rules. It leaves me scratching my head trying to understand how the genetics work to produce that anomally. There seem to be some recessive genes that don't crop up very often in certain combinations and when they do - Surprise! Like the cases where a Red mated to a Dun can produce a Black. That one gets me confused. :p

[Woodmagic]

Recessives don’t break the rules; it is simply that chance has allowed the recessive to be inherited through many generations, but only with the copy coming from one parent. When many generations later, a second parent also throws it, something that you were unable to suspect suddenly evinces itself, because the calf collects the two recessives and you can see it, the double gene allows it to have effect
The Cardiff project has another year to go, it is fascinating. It is not a question of stronger genes. The amount of crossing must be more limited than we feared. Looking at the charts that they have produced, I was amazed at the extent some breeds have been invaded by others; we are squeaky clean compared with some.

[Kirk- Cascade Herd US]

Surprise! Like the cases where a Red mated to a Dun can produce a Black. That one gets me confused. :p

Here's how I keep the Black/Dun/Red Genetics straight:

The three base colors of Dexters (and all cattle) are controlled by the genes at the E (Extension) locus. The three base colors aren't Red, Black, and Dun, they are Wildtype Red (E+), True Red (e) and Black (ED). So all Dexters either have red genetics or black genetics.

Now if a Dexter with one or two dominant black (ED) genes at the E locus also carries two copies of the recessive (b) dunning gene at the B (Brown) locus, then that alters the black pigment to look brown (by interfering with the last step in laying down black pigment). So duns are really just unfinished blacks.

So when you mate a red to a dun, you're really mating a red to a genetically black animal that also has two dun genes (b/b). While the dun parent (b/b) must pass one dun (b) gene to the offspring, if the red parent doesn't carry dun, or has one dun gene but doesn't pass it, then the black offspring won't receive two copies of the dun (b) gene and therefore its blackness won't be modified to dun.

So Red X Dun can = Black and its genotype would be one of the following two combinations: ED/e B/b or ED/E+ B/b (depending on which type of red gene the red parent passed).

[Mark Bowles]

This topic has now had over 3600 views, and 53 contributions from all over the world.I must say i have found it far too complicated for my little brain but i take my hat off to those of you who understand it all in great depth.
At least its all down in writing to go over and over again to try to get some grasp of the subject
Thank you all very much.
Mark

[Inger]

Yes I have heard of Dun being described as a diluted Black. But that the dilution gene was located on a different point in the DNA strand. So by your description, Red genes are recessive to Dun then. Which would explain why the resulting colour is in the Black colour range, rather than the Red.

So am I correct in asuming that a Dun animal would have to carry Red in order for a Dun/Red mating to produce a Red calf?

[Inger]

Understanding genetics better, helps us to anticipate possible outcomes Mark. I think that's what fascinates people the most, being able to make more educated guesses. But yes, trying to understand some of it can produce headaches. :laugh:

[Kirk- Cascade Herd US]

Yes I have heard of Dun being described as a diluted Black. But that the dilution gene was located on a different point in the DNA strand. So by your description, Red genes are recessive to Dun then. Which would explain why the resulting colour is in the Black colour range, rather than the Red.

So am I correct in asuming that a Dun animal would have to carry Red in order for a Dun/Red mating to produce a Red calf?

Geneticists would steer us away from using the word "diluted" because that word is already used for a dilution gene that causes other color variations in other breeds of cattle. So we should probably use the word "modified".

Red really isn't "recessive" to dun because the dun gene is located at a different locus (the Brown or "B" locus). How it really works is that at the E locus, true red (e) is recessive to wild-type red (E+) is recessive to black (ED). These 3 choices (called alleles) at the E (extension) locus direct the "extension" ,across the animal, of the only two pigments that nature has to work with in most (all?) mammals; the black pigment called eumelanin and the red/orange/yellow pigment called phaeomelanin. True reds (e) have only red pigment, wild-type reds (E+) have mostly red pigment with some black pigment (usually at extremities), and blacks (ED) have lots of black pigment (hiding any red pigments).

At the B locus, there are two choices, Neutral (B) and dun (b). Neutral is dominant over dun. The dun gene only has an effect on black pigment (by causing the last step in laying down the black pigment to be omitted). Because the two types of reds have little or no black pigment, then the dun factor isn't apparent with reds (although, we're having a debate in the US about whether an E+ wildtype red with two dun genes might actually show some hard-to-spot dun extremities where black extremities should be in an E+).

So red is recessive to black, and dun can only affect (modify) black pigment. And... yes, you are correct in assuming that a dun (modified black) animal would have to carry red in order for it to produce a red calf, when mated to a red animal.

Hope this clarifies more than it confuses...

[Kathy Millar]

Well put, Kirk. Life (genetically- speaking) was very simple in my little Dexter world...until I had a dun show up this year. She was out of two blacks so now I know that my black cow is EDe (she has produced reds too) and Bb. Quite the little colourist is my Daphne. :D

[jim]

I am wondering if the recessive colour genetics might be visable on our animals. Especially as calves I have noticed that some animals have a red tinge, most notably at the extremities, and some do not. Over time this shading will fade but still be in evidence in the long over coat of winter hair. Last year we had our first dun calf and this year the same dam, same mating, had a black heifer with brown ear tips and tail tip [cute as a button]. So I assume that black animals with a red tinge are black with a red recessive gene, black animals with brown tinge are black with a dun recessive and animals without any tinge are black\black. Is this basicly true?