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Posted: Wed Mar 21, 2007 9:08 pm
by Rob R
I have one cow in the herd (bought in) that has a common Grandsire, and was just looking at a heifer for sale which shares a Granddam with one of our bulls. Having spent time looking through some of the pedigrees on the DCS website, I was wondering how close you would breed two animals with a common ancestor? Grandparents? Great Grandparents? GGPs? Or further?
I've just noticed a Stage 1 bull with a common grandsire, so it must not be an issue for the EBS.
Posted: Wed Mar 21, 2007 11:39 pm
by Kirk- Cascade Herd US
I don't believe there is any such thing as too close if you have a planned purpose for the particular breeding. Here's a copy of a reply I wrote to a similar question on another board some time ago:
Inbreeding/linebreeding, along with selection and heavy culling, is a powerful tool used to create excellent family lines within breeds of animals. Inbreeding increases the odds that any existing good genes will pair up and express themselves. However, it also increases the odds that any existing bad genes will pair up. Since most bad genes are recessive, they only exhibit themselves when there are two copies. Inbreeding does NOT create problems. Inbreeding forces hidden recessive bad genes to the surface where they can be culled. Outbreeding / outcrossing simply hides the bad genes and passes them on to the next generation.
A novice breeder, especially those without a good eye for selection and those unwilling to cull heavily, should stay away from inbreeding themselves, BUT should be happy to acquire excellent animals from an expert’s inbreeding/linebreeding program.
Animals from a well-managed inbreeding/linebreeding program are likely to be homozygous for excellent traits and likely have had most negative traits culled out. These inbred/linebred animals are considered prepotent. Because they have two copies of good genes, they will definitely pass those good genes to their offspring.
If you are considering breeding two related animals, consider these questions: Are those two animals top quality to begin with? Does the common relative have some outstanding characteristics and few flaws? Do you have an eye for excellence? Can you spot flaws? Are you willing to ruthlessly (and humanely) cull the rejects? If you answer yes to these questions, then you should not be afraid of inbreeding. If you answer no to any of them, then you should stay away from inbreeding/linebreeding (especially if you are unwilling to heavily cull).
Hope this helps...
Kirk
Cascade Herd
Posted: Thu Mar 22, 2007 12:06 am
by Duncan MacIntyre
An exellent reply from Kirk, I would endorse every word. As some will know I am currently using an inbreeding programme and so far the benefits seem to me to be outweighing the problems.
Duncan
Posted: Thu Mar 22, 2007 2:06 am
by Rebecca
I would just like to point out that although an inbred animal may be homozygous for particular traits (and thus prepotent) these will not necessary show in the phenotype of the offspring, in the case of recessive genes.
Using the red colour as an easy example: for the phenotype to show red the animal must be homozygous red as the red gene is recessive. However breeding this animal to another only guarantees that it will pass on one of its red genes, whether the resultant offspring is red depends on the gene it receives from its other parent. Prepotent animals will pass on the desired gene and if it is the dominant gene it will always show in the offspring, but if recessive may not. Of course this gene may then be lost in the next generation unless you breed to another animal with the desired gene, hence where linebreeding comes in! :D
Posted: Thu Mar 22, 2007 4:42 am
by wagra dexters
Kirk, would you be happy to offer your posting to our Editor for inclusion in the next Australian Bulletin?
Rebecca, I think you answered your own argument very nicely.
Margaret
Posted: Thu Mar 22, 2007 4:50 am
by Kirk- Cascade Herd US
wagra dexters wrote:Kirk, would you be happy to offer your posting to our Editor for inclusion in the next Australian Bulletin?
Rebecca, I think you answered your own argument very nicely.
Margaret
Yes. I'm honored to do so.
Posted: Thu Mar 22, 2007 5:55 am
by Inger
The new bull calf we are getting is the result of a brother to sister mating, from a bloodline that is arguably one of the best Dexter Studs in NZ. The bull calf is of no use to the breeder because he needs a heifer calf from the mating and couldn't use the bull calf in his herd anyway, but for me its a concentration of many traits that I'm looking for to improve my heifer line and he'll be used over heifers from mostly completely different bloodlines or only related by one grandparent from the same stud and the foundation dam in the bull calf's stud.
This breeder has mated mother to son because he couldn't find another bull in NZ that he wanted to use over the mother. Both were excellant examples of the breed. The brother to sister mating was to see what happened. He is quite happy to eat under par animals. (Although his under par might be other people's not too bad). :D
Posted: Thu Mar 22, 2007 10:53 am
by wagra dexters
Many thanks, Kirk. I have emailed Jean, and if she isn't in hibernation, recovering from another excellent bulletin, I expect to hear back shortly.
Posted: Thu Mar 22, 2007 2:01 pm
by Rob R
It's a subject I wanted to look at for my BSc (but was unable to in the end), looking at the Chillingham herd & viability.
"Although his under par might be other people's not too bad"... This statement makes very true when looking at the viability of breeds- the long term importance being more in diversity of available genes than the way they are used, illustrated by the the narrowing that has occured in world of dairy cattle via AI. It also crosses over with the concerns raised on the bull scheme topic about the dangers of narrowing the genepool with a perceived 'elite'.
I'm not worried about my own animals, as I know they have come from lines of experienced breeders (hence the reason they were selected for the herd) and I've seen the converse effect that close breeding can have, in an unregistered animal that I now come to own (which has reinforced my already strong opinion that it is important to register animals, as memories are quickly lost & faults/merits are hard to trace without a good record).
Please keep the comments/experiences coming though...
Posted: Fri Mar 23, 2007 5:34 am
by Rebecca
The problem with line breeding is that althou
Posted: Fri Mar 23, 2007 9:23 am
by Woodmagic
It seems to me Rob that you are working it out pretty well for yourself. I envy you the chance to evaluate your bulls through hiring out, if your bull can provide good stock from a wide variety of outsourced cows he will be doing well.
For the amateur, choosing an animal that is known to be inbred, but is not related to ones own stock, can only be an advantage, if it is carrying qualities you hope to breed for, since what is evident in that animal is likely to be passed on.
Few breeders inbreed, preferring the safety of out crossing to avoid the possibility of doubling up on undesirable genes. The disadvantage is that it has to increase unpredictability.
I become very impatient with the emphasis on looking at an animal in order to assess its breeding qualities, when all you can see is the evidence of the influence of a blend of the two genes inherited by the animal from its two parents, a blend it cannot pass on. If linear assessment was used simply to assess the value of the animals on the ground I would have no quarrel with it, but it cannot tell you how the next generation is going to turn out. It can tell you what you should be aiming for, but not how to get there.
The day will come when a DNA assessment will give you the answers, meanwhile I suggest the best the breeder can do, is to gauge as far as practical, the pool of genes the animal has inherited from and may be carrying; or lay the bull off for five years and wait to see what it has produced. The satisfaction when you succeed makes it all worthwhile
Posted: Fri Mar 23, 2007 11:19 pm
by Inger
Very true. Unless an animal is cloned, its complete genetics can't be passed on to its offspring. What you need to find out is which traits are the bull's strongest and most likely to pass on? Does the bull pass on his best traits to his daughters or his sons? Or is he a middle of the road bull that produces equal value sons and daughters. Either type has merit. For grading up, good daughters make an excellant foundtion to a herd.
Taking a look at a bull's relatives and any offspring he already has on the ground, is a very good way of getting an idea of what to expect. If the strongest traits a bull produces are the ones that your herd needs to improve a weakness, then that's the bull you should use. The resultant calves will still be a gamble to an extent, but you'll be making an educated guess, by doing your background checks.
As Woodmagic says, it takes a number of years, but the success is oh so satisfying. :D By doing your homework, you increase the chances of producing the herd that you're aiming for.
Posted: Fri Mar 23, 2007 11:27 pm
by Duncan MacIntyre
But remember you cannot credit or blame the bull for all his daughters. I have been asked advice more than once by breeders who have relatively new herds who were disappointed by the variation in their calves. My simplistic advice has been to breed a crop of replacement heifers all off the same bull, then if you like use a bull from different lines on them, but when you do you will get much more consistent calf crops than when all the cows are from assorted breeding. The trick of course is to get the type you like.
Duncan
Posted: Sat Mar 24, 2007 6:44 am
by Kirk- Cascade Herd US
To second Duncan's excellent advice and provide an example, when we started our herd, we purchased 7 half-sister heifers and their niece out of an excellent bull strongly linebred back to Luicifer of the Knotting Herd (their dams were all interrelated too, from one of the oldest and best linebred herds in the US). We then used our new homozygously polled bull, heavily linebred to Saltaire Platinum, as a cross (to introduce the polled gene). We were thrilled with the quality and amazing consistency of the calves. We had eight polled calves (including 6 females) on the ground within a three week period and they looked (and still look and act) like a very tight little herd.... and the icing on the cake is that they are exactly the type we like.
Posted: Sun Mar 25, 2007 11:30 am
by Inger
Our Salty bull stamps his heifers with the same look of a straight back, nice head and reasonable depth of body, no matter which cow he is put to, but then he is descended from a linebred Canadian herd where all the females in the herd are very similar. Their owner says she could put a ruler along their backs and they would all be very close to each other in height.
Line breeding used properly can produce good results, but you need to start with good genetics in the first place.
In our herd, I started with cows of several bloodlines and used the same bull for a few years to observe which of those cows were best suited to the hill country and poor grazing on our property. The cows that couldn't maintain their own weight and raise a calf well at the same time, have been sold to a farm with far better grazing than we have. The cows which had poor temperaments have been eaten.
As the bull has shown himself to be very resiliant in health and feet, I've kept all his daughters, even from the cows which couldn't cope with our land. I will keep observing and collecting data on their production abilities (the offspring they can produced) and keep choosing the animals that perform best on our property. For our purposes, that's the kind of Dexters we need on our land. The rest will continue to be sold to easier properties or eaten. I don't plan to buy anymore female lines, just work with the ones we have and use bulls to remedy flaws in their makeup. We'll see what happens. Whether or not I'm brave enough to start using our own home grown bulls will depend on how good we can grow them. I think I will definitely get a cattle judge's opinion of his worth before using a home grown bull though. We have a very good judge in our Society and I trust her opinion in the worth of an animal.