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Post by midhilldexters on Jan 30, 2015 11:49:19 GMT -5
In another thread Kirk said this PS. I believe all AI Bulls should be considered highly experimental until they breed at least 10-20 of their own daughters with results reported. A great bull should be able to be bred on many of his own daughters and get great results. This would also help uncover any hidden problem genes/lethal genes before those genes are spread far and wide. What are everyone's thoughts on this? Do you think it possible within our breed? Do you feel that you would use an AI sire that has no progeny on the ground that you could view? I've never had a bull collected, I nearly had Kevan collected but in the end decided to sell him. Other than him I don't think I have had a bull that has been worthy of collection, yet. Being a small breeder I've always just kept a bull long enough to evaluate a couple of years of breeding, and either sold him if he's been good enough quality in my eyes or beefed him. I certainly agree with the concept of uncovering hidden lethals, just not sure that smaller breeders could accomplish it the way Kirk explains it. Carol K
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zephyrhillsusan
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Caught Dexteritis in Dec. 2009. Member of this forum since Oct. 2013.
Posts: 1,502
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Post by zephyrhillsusan on Jan 30, 2015 15:12:29 GMT -5
I imagine some breeders are already doing something similar, but I know that we would never be in the position to be able to do it on the scale Kirk talks about. On the other hand, we're not planning on collecting our bull, either. We only have enough pasture to keep a few cows, so we can't keep very many of our bull's daughters long enough to get them to breeding age, breed them, and see the calves on the ground. I have recently revised my hopes, although some of it will depend on the agreement of my husband who pays the hay bill. I had originally not planned to keep any of his heifers at all, but now I would like to keep one (well, two at least, but I have to sneak them in there one at a time!) all the way through to calving. Like I said, I have to take my husband's wishes into consideration, and we are "land-locked" with absolutely no possibility to get more pasture. I originally got him to agree to "a cow." Then we had a cow and her heifer and a steer we bought from someone else to eat. Then I wanted a second cow. We ate one steer and got two more. Then we couldn't get the AI guy to bother with small-timers like us, so I wanted to bring a leased bull onto the farm so I could continue to milk. Then when his owners stopped leasing him, I started making noises about a bull. Not just "any" bull to give us freshened cows and calves to eat, but a bull whose calves anyone would want to own. DH let me ship a bull from the opposite side of the country, so I think he's come pretty far from letting me get "a cow" five years ago! I don't intentionally plan to keep "sneaking" things into the program, but each time we go one step farther, I begin to see the next logical step. Right now, that is keeping "a" heifer of Royal's to breed to him. Hey, DH has a while to get used to that idea before I float keeping two! (I'm SO glad he doesn't read this forum!) ROFL! So anyway, Carol, that's why we are far, far away from ever being likely to implement the really excellent breeding practices--AI or otherwise--that several breeders with more animals use. But I hope we're being more responsible than the average "backyard" breeder. We've already made the decision to castrate one very sweet polled red chondro-positive bull calf because I believe (learning from posts here) that his dam is not "bull mother" material. Other Dexter breeders whom I respect have been happy to buy three heifers we got by AI and leased bulls, so I hope we're on the right track as far as culling. (I know this is off topic, just throwing it in for the record.) I see your point, Carol, that with so many smaller breeders in the Dexter breed (like us!), that it might be very difficult to accomplish. As the ADCA AI bull catalog stands, it's a confusing mishmash for anyone who's bull shopping. Practically every bull on the list has different information given in a different order and format; very few of the listings even mention their calves' quality or birthweights. Even if you look up a bull's progeny on the pedigree pages, very few of them will have photos, much less any that actually show anything about the calves. Many Dexter breeders don't have websites, much less have photos of their calf crops posted where anyone can easily find them. So if you want to know about a certain bull, you're pretty much reduced to calling and emailing owners--and they are sometimes not even the ones who collected and are selling the semen. So even if breeders are proving their herds according to this method, would we even know about it? I hope they'll chime in here with lots of photos!
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Post by legendrockranch on Jan 30, 2015 17:01:31 GMT -5
As the ADCA AI bull catalog stands, it's a confusing mishmash for anyone who's bull shopping. Practically every bull on the list has different information given in a different order and format; very few of the listings even mention their calves' quality or birthweights. I agree Susan. For me, even though I do have enough animals and have bred 10-20 sires to their daughters, I still wouldn't collect a bull for AI unless it was for my use only. The ADCA AI list does have a few nice bulls on it, there are also the questionable ones. It is the breeder’s choice to list an animal, I just feel the ADCA should hold its AI bulls to the highest possible standards, the best of the best. Now it's any ones game, proven or not. Barb
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Post by Cascade Meadows Farm - Kirk on Jan 30, 2015 19:04:58 GMT -5
Perhaps we should just include some information on each bull like this:
This bull has been bred on 9 of his own daughters This bull has also been bred on his own mother, twice. All pregnancies were carried full term, with no known miscarriages All 11 calves were normal and healthy and delivered easily Calf weights were 44, 45, 46, 50, 52, 44, 45, 51, 53, 55, 47 pounds
We should post educational information explaining that the more daughters a bull is bred on with good results, the more likely the bull is not carrying any hidden lethal/problem genes, and the more likely he is carrying lots of good genes.
All other things being equal, it would be wiser to choose a bull that had bred more daughters successfully, than one that had bred few or no daughters successfully.
PS. It's funny that fear of inbreeding, is what has allowed for lethal/negative genes to creep deeply into many breeds. Many people WRONGLY assume that inbreeding CAUSES problems so they avoid it....Avoiding inbreeding, just passes all those hidden negative genes to the next generation. But inbreeding doesn't CAUSE problems... It just allows existing problems to show up, so they can be dealt with. Daughter testing is the BEST way to find these problems before they spread.
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Post by lakeportfarms on Jan 31, 2015 7:19:49 GMT -5
Listing a bull's height at 3, and even more so 2 years of age is difficult to reconcile with the other goals (stated by some here) of evaluating the progeny of the bull along with the traits the calves carry, because there is limited experiences to make any kind of determination. For example, how do you know a bull improves udders if collected and the information is published at 3 years of age and never updated? Most ads are not, or the are selectively updated with only the favorable information as a bull ages. His first calves on the ground are, at best, barely at calving age themselves when the bull is 2 or 3 years old!
I suppose "just in case" you could measure a bull at 2-3 years of age if you THINK you may be collecting it, but often times the decision made to the collect comes at a later age, after you've had the ability to evaluate a sufficient number of his calves, and/or he has performed well against his peers in a number of shows and proven his capabilities. I suspect bulls measured and collected at a young age are done so because they carry an immediately known and verifiable trait such as polled or A2/A2 milk status over anything else. Making a comparison of a bull measured and collected at 2 years of age against one collected at 5,7, or 9 years of age will yield many different interpretations of the results by owners looking to select one to AI their cows, especially with regard to height.
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Post by midhilldexters on Jan 31, 2015 8:55:25 GMT -5
Of course the curve ball on listing heights is, should we be rallying for two breed standard heights first, one for non carrier and one for carrier?
Carol K
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Post by cddexter on Jan 31, 2015 11:35:47 GMT -5
two height standards? Oh dear, near and dear to my heart.
However, as Patti has pointed out numerous times, until everyone tests for chondro, it's a crap shoot. Personally my preference is to put a two-height system in place, with a field that allows either chondro tested, or not tested but best guess. At least we'd have SOMETHING to work from instead of this gross misunderstanding we have today. And, maybe it would go a long way to silencing those who claim that Dexters are getting bigger because nons are being registered now when they were being eaten instead, 30 years ago. I can remember some Tak Sca Hav cows in the 47-8 inch range, but everyone thought their dwarf offspring were 'just right'.
Yetch.
me.
PS: back to the topic. Maybe if there were multiple suggestions to Directors or the Pres that we have a standardized format for AI bull info. Fields can be missing, but at least there'd be a place to put the stats in some kind of order, and it might give pause to those who don't provide the info, because their bulls might not be as popular as the ones where you have a better idea of what to expect. It's been years since I did up the AI Bull Review booklet, but I know there are some who still refer to it. See....
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zephyrhillsusan
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Caught Dexteritis in Dec. 2009. Member of this forum since Oct. 2013.
Posts: 1,502
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Post by zephyrhillsusan on Jan 31, 2015 14:09:31 GMT -5
Probably hard to do if you raise a ton of animals, but . . . I learned from Kim Newswanger to mark down basic stats at birth, including certain measurements, and to keep it in a file (I have mine both on the computer and printed out in a file folder). I have a sheet I use now when I take birth measurements, and I try to update the first three years on the animal's birthday (or close) so I have a record of their height-weight growth curve. I'll probably quit at 3 years, but at least I will know it and have it written down. I do both hips and shoulders because depending where you look, it's hard to be sure which the "official" measuring place is. And then if I see someone else's measurement for hips, I can compare that with mine; if their measurement is shoulders, I can compare that, too.
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AI Sires
Feb 1, 2015 15:13:06 GMT -5
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Post by RedRidge on Feb 1, 2015 15:13:06 GMT -5
Hard for me to comment since the only semen I have ever used is my own, and it wasn't dexter. My view about collected sires seems to be different than most - I collected sires who I felt were superior specially for the purpose of line breeding years down the road should my hopes for an even better son be shattered, or the quality of son and sire are so similar that I have line breeding options.
Let's say I view collected semen as an insurance policy. I learned years ago that the true value of a sire is not known for years. If, in the early years, I get an inkling (not knowledge or fact, but just enough info that I have reason to hope) that I've produced something that exceeds my previous genetics - then I collect. Why? Because a good breeding program should eventually produce offspring superior to their parents. But... it's all too frequently a "hind sight is 20/20" kind of knowledge. So... if all goes as planned, a superior son will eventually be produced - rendering than frozen semen more valuable and useless all at the same time. Useless because I don't know how the son will reproduce but hope he will, and valuable because we know the sire will. If it doesn't go as planned I need to reevaluate why? Were the cows not of quality? Was he not prepotent enough? Etc... if all the reasons point to the human factor, then at least I have quality semen to fall back on. If it doesn't, I need new genetics.
The flip side is that providing semen to others, carries an implied knowledge that the owner of the semen really doesn't have. Buyer beware iow. I have yet to see a collected dexter bull I would consider breeding to. Some of the collected bulls may be awesome, but... prove it.
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Post by littlecowfl on Feb 13, 2015 11:27:20 GMT -5
Breeding a bull back to his own daughters to prove him might be doable, but what does that really tell you? It tells you that 10-20 of the daughters PHENOTYPE showed nothing immediately threatening to the breed. It doesn't tell you the GENOTYPE, or what genetics the daughter actually have. You still don't know if the bull really doesn't pass on any lethal genes. You could have still been just lucky. How many of us carry genes for cancer or Parkinsons. Do we know? No, of course not. We might find out later, but we don't know from our phenotype. So these heifers could be like ticking time bombs that when combined with certain lines, suddenly show a deleterious recessive. So, what does a responsible breeder than do with those daughters? If you slaughter the daughters, no harm can come from the test. If you sell or breed the daughters, you still risk passing on concentrated genetics to the next generation that contain something harmful to the breed in the long run. You might not know until far too many generations have been produced. The genotype of the offspring might just produce something lethal down the road.
The closer the cross, the less genetic variation in the offspring, which means more recessive genes can be expressed. It also means far more repeats in the genetic code which can make entirely new traits appear. Many of us already have concentrated bloodlines through breeding near lines. If you check out the bloodlines of ten random Dexters, you will likely see several relatives in each one. Every close cross concentrates while every out cross dilutes. I understand this from a biological standpoint because I have two degrees in biology. The closer the cross, regardless of whether or not it's father-daughter OR grandsire-daughter + cousins+ granddam-son, will only tell you if a deleterious recessive gene is inherited in the first generation. Again, what you see is phenotype (color, shape of udder, tailhead set). What the animal carries is genotype (the arrangement of ATGC into codons). The genotype is what can get us in trouble down the road when we suddenly see the phenotype of a deleterious recessive (PHA, for example). By then, it's too late. When you trace the genes back to to the originator, you'll find a random crossing or specific recessives that combined to create something bad. So, testing these animals by breeding back to sires and then allowing those test animals to continue to breed, since we saw nothing immediately wrong with the phenotype, is not a good idea. You can't see any hidden recessives. It's like testing the sharpness of a knife by seeing if it cuts your arm. You're too late! Now, you're bleeding.
So, the real questions should be:
1) Does the test tell us something important enough to breed sire to daughters? Is a good test, or a possible way to unwittingly introduce deleterious recessives into future generations?
2) Can we afford to slaughter the daughters to ensure the test animals don't have hidden recessives, especially since there already are many related crosses in Dexters which reduce overall variability, without resorting to sire-daughter crosses?
3) Is there a better, safer test for potential sires?
Some breeders purposely breed close crosses to try to concentrate genetics of animals they believe to be high quality, but I wouldn't call that a bull test. That is commonly done in many domestic animals in pursuit of a winning show animal. Whether that's a good practice or not needs to be decided by each individual breeder based on their own ethics.
The best, and safest, test I can think of for a bull takes time. I want to see the results from crosses with various bloodlines to see how much influence the bull has on his offspring in both physical traits and temperament. All I will see is the phenotype, but if I can see what the bull produces with different crosses, I can know what he is likely to improve in my cows. That will tell me enough to choose that bull or not without causing any future harm to the breed.
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Post by Cascade Meadows Farm - Kirk on Feb 16, 2015 19:10:35 GMT -5
Breeding a bull back to his own daughters to prove him might be doable, but what does that really tell you? It tells you that 10-20 of the daughters PHENOTYPE showed nothing immediately threatening to the breed. It doesn't tell you the GENOTYPE, or what genetics the daughter actually have. You still don't know if the bull really doesn't pass on any lethal genes.
Daughter testing is the #1 best way to find unknown recessives and to learn other things about a bull's genotype. This testing causes NO problems, it just uncovers existing problems.
Here's an outtake from an article from a friend:
"We now have DNA tests for some defects,
such as Chondrodyplasia in our own breed, but such tests do not show anything other
than the one specific problem. The only real method of testing for all genetic defects is
progeny testing. It is possible to tell quite a lot from mating a bull to any close relatives,
but the best way to tell if a bull carries any undesirable genes is to mate him
systematically to his own daughters. On average, any genetic defect will be inherited by
half the bull's daughters, so mating him to those daughters offers a good chance of
detecting if the bull is a carrier of such a defect.
In any mating there will always be four possible combinations of genes in the
offspring for any particular characteristic, with many defects being controlled by a single
recessive gene. A bull carrying such a gene will pass it on to half his daughters, so mated
back to him there would be a 1 in 4 chance of those daughters producing the actual defect
in their calves. The other half of his daughters, which would not have inherited the
defective gene will not produce any defective calves, that is 4 chances in 4 of not
producing the actual defective condition. So mating to unselected daughters gives an
overall chance of 1 in 8 that the actual defect will appear.
Obviously, the more test matings you make, the greater the chance of detecting any
undesirable genes present in the bull. Mating a bull to one of his daughters gives only a
12.5 chance of revealing any defective gene, but mating to six daughters raises the
detection level to over 50%. That means you're more likely to find the problem than to NOT find the problem with just 6 test matings.
There are obvious drawbacks to this procedure, notably that is takes years to do with
the attendant costs. However, it is a very wise precaution for a bull likely to be widely
used, especially on A.I., where it is now possible for semen to be distributed worldwide.
Remember a bull will pass on any genetic defect he has to half his offspring, increasing
the hidden problem within the population for those recessive genes carried by him.
Progeny test mating (prospective parent to own offspring) tests for all undesirable
genes rather than just one.
Over the years, various genetic defects have appeared in every breed. Sadly some have been produced by A.I. bulls and others widely
used for service. Certain defects have also been attributed to these bulls where they have
been a common ancestor of problem animals. It is quite possible that the defective genes
could have been prevented from being distributed across the breed population if the bulls
concerned had been progeny tested before being widely used, particularly if intended to
go on to the A.I. panel."
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Post by littlecowfl on Feb 17, 2015 11:23:02 GMT -5
I understand the theory from the cattleman's perspective; but I don't agree as a scientist. Genetics is much more than what you see and the implications on future generations cannot be adequately predicted or controlled, especially if the first generation from a sire/daughter cross is allowed to breed.
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zephyrhillsusan
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Caught Dexteritis in Dec. 2009. Member of this forum since Oct. 2013.
Posts: 1,502
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Post by zephyrhillsusan on Feb 17, 2015 14:18:42 GMT -5
Some of the best herds have been extensively line bred, if I understand correctly. cddexter, kansasdexters and legendrockranch might know more specifics, including any stories of epic failures that had to be culled. Obviously, this principle is dependent on conscientious culling on the part of the breeder. In fact, any good breeding is, isn't it? Here's the thing, if I understand correctly . . . with any AI bull you use on your cows, you still have the same genetic "crap shoot." There could/would still be things that wouldn't visually show up and would only come out with further breeding, right? (I'm speaking here from the standpoint of someone who enjoys genetics as a hobby, but lays no claim to being any more of a scientist than any RN has to be. I know that I picked an AI bull for a cow because he was supposed to improve feet and udders. Yes, the feet were better and the udder was somewhat improved, but a breeder I respect said, "I thought Bull X would have done better on her udder." Knowing then what I know now, I could have made a wiser choice for udder improvement. Of course, I was so new to Dexters at the time that I didn't know there were other choices out there besides the bulls on the ADCA AI sire list. I did call people and ask for advice, but I didn't know many breeders and didn't want to "impose" by asking for advice. Now I would have a lot more resources at my disposal--and be a lot less shy about using them. Kirk's post has gotten me interested in keeping a heifer (or two) if we are lucky enough to get any (hear that, Heifer Fairy?) and breeding them back to our bull--just to see what we get. midhilldexters, you are right that it will take us years to be able to accomplish anything, starting with just two cows and a maximum possibility of two heifers. But I'm interested in trying, so we'll see . . .
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Post by cddexter on Feb 17, 2015 14:56:38 GMT -5
Or you could chat with Marion. she's used several related bulls, which has had the effect of line breeding.
Once you are pretty sure of the genes available, it's safe to promote the bulls and linebreed knowing there aren't any (or seriously few) traits you don't want, along for the ride. cheers, c.
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AI Sires
Feb 17, 2015 16:16:17 GMT -5
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Post by triplec on Feb 17, 2015 16:16:17 GMT -5
Interestingly, before the advent of genetic testing for recessive traits the only way to statistically ensure genetic “purity” of a bull/ram/buck etc. was to breed that bull to 35 of his own daughters concurrently. If no genetic defects show up in any of the offspring, the bull is 99.7% likely to be genetic defect free. - See more at: onpasture.com/2014/10/20/breeding-matters-iii-inbreeding-vs-line-breeding/#.dpuff you read the article. Kirk's comment comes from the information that before genetic testing. I assume it would apply if looking for a unknown reccessive trait.
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