November 29, 2011 at 08:01 #20367KenhParticipant
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Thought people may be interested in this on the BBC websiteNovember 29, 2011 at 09:50 #380139% MANParticipant
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You beat me to it in posting the link.
An interesting article which poses many questions and as it admits in the article the ramifications are inconclusive.
However as it also points out continued inbreeding can cause problems as has been evident with some breeds of dogs.November 29, 2011 at 12:09 #380160SteeplechasingParticipant
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Sorry, should have checked here first as I’ve just posted on twitter which some of you might already have done.
Fascinating stuff nonetheless
Never argue with a fool. He will drag you down to his level and beat you with experience, then onlookers might not be able to tell the difference. https://lazybet.com/November 29, 2011 at 14:27 #380172andyodMember
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Reminds me of the shutin who said her cat could not have gotten pregnant because Tom was her brother.November 29, 2011 at 16:48 #380186AnonymousInactive
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I ddi find that most interesting once i’d got beyond that nonsense about inbreeding causing broken legs! Anne Herries =almost a neighbour of mine then, used to get quite cross when so few wanted to send mares to her beloved Celtic Swing, and seh made almost this point – ther’ell be trouble if they keep sending all the mares to so few stallions, espcially Yankee ones race’d on LASIX!
ConstanceNovember 29, 2011 at 17:54 #380197moehatParticipant
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steeplechasing; did you put a link up a while go about an owner who made a point of only buying horses from pedigrees that didn’t suffer from breathing problems? I kept meaning to re read it but then forgot which thread it was on. Found it very interesting. Thought Celtic Swing didn’t have very good conformation? We were at the National Stud in Ireland shortly after a Celtic Swing foal had been born. Wish I’d made a note of it, so I could’ve followed it’s career.November 29, 2011 at 19:50 #380216freeradicalMember
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Negative in breeding will start becoming apparent when increasing number of sires become either infertile or mares start increasingly losing their foals due to recessive inherited leading to spontanuous miscarriage. It is probably well documented how frequently pregnancies are lost and these sires that carry these recessive traits will not have long careers.
If there were to be a percentage increase in non-deleterious recessive traits in the horse population these are likely to lead to reduced fitness. Again something that will be noticable if fewer than expected of the off spring perform. While an increased predisposition for bone breaks could be genetic, you would expect it to be linkable to certain sires or blood lines. To study this it would be important to determine how the bone broke e.g. during a gallop or was there evidence that the horse put its foot in a hole etc. The same would apply to heart conditions and breathing issues. Again making simple group would not be valid as you would need to study the specific condition. If no significant linkage can be made then these would either be possibly due to de novo mutations, rare recessive genes, or multifactorial elements rather than a single gene.
In breeding will always be a potential problem in a limited gene pool. However, given that the major breeders often take the both the long and short term view, I would expect there to be sufficient ‘outbreeding’ to ensure the race horse continues to thrive. The major danger would be again allowing artificial insemination, which is likely to result in a reduced gene pool.November 29, 2011 at 20:31 #380221moehatParticipant
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Find genetics fascinating, although must admit to also finding it very difficult to understand. Having a problem with my dog at the moment, and, in the course of trying to get to the bottom of what’s wrong I’ve been told some genes are more ‘dominant’ than other. Which genes
would be like this in horse breeding?November 29, 2011 at 21:47 #380232Miss WoodfordParticipant
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I challenge the assertion that pedigree is the reason behind breakdowns of recent years.
There has been just one equine fatality in 136 runnings of the Kentucky Derby. Eight Belles’ sire Unbridled Song does tend to sire precocious, unsound horses (see Midshipman, Old Fashioned, Buddha, Dunkirk, Songandaprayer, Rockport Harbor, Half Ours, Winslow Homer, Silver City, etc.). However, several UBS offspring have run for years because they weren’t pressed hard along the Triple Crown trail. Also, Eight Belles’ half-brother Escape Route (inbred 3×3 to Mr. Prospector and 3×4 to Northern Dancer!) is still running well as a 7yo.
With Barbaro, however, there is nothing in his breeding to suggest a likely breakdown. In fact, his sire Dynaformer is the go-to sire for soundness and stamina. He is the leading jumps sire in the United States. His best offspring include Perfect Drift (retired sound at age 9 with over $4 million in earnings), Americain (Melbourne Cup winner), Riskaverse (retired sound at age 6), Film Maker (retired sound at age 6), McDynamo (3-time champion steeplechaser, retired sound at age 10, currently a foxhunter), and several G1-winning hurdlers. Barbaro’s dam, La Ville Rouge, raced 25 times, and none of Barbaro’s siblings/half-siblings have shown any fragility. Barbaro is 4×5 to Nashua, who himself had stamina to spare and sired tough horses like Shuvee, Wickerr, and Diplomat Way.
Rewilding’s pedigree isn’t particularly unsound, either. His only inbreeding in 5 generations is 5×5 to Natalma.
In breeding will always be a potential problem in a limited gene pool. However, given that the major breeders often take the both the long and short term view, I would expect there to be sufficient ‘outbreeding’ to ensure the race horse continues to thrive. The major danger would be again allowing artificial insemination, which is likely to result in a reduced gene pool.
Standardbreds have allowed AI for a long time, and they’re as sound as ever. Race once a week, sometime in heats, and 300 or 400 lifetime starts isn’t uncommon. You are correct that AI has reduced the gene pool in them and in racing Quarter Horses (it is literally impossible to find a racing-bred QH without Dash For Cash or Beduino blood), but that hasn’t resulted in soundness issues.November 29, 2011 at 21:57 #380234EmmyKMember
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I think a bigger problem is the shear volume of horses bred? and we have this bizarre thing in the UK where by we don’t really use the best mares we could 99% of the time, and that slowly drives down standards in all ways.November 29, 2011 at 22:01 #380235AnonymousInactive
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What a pathetic article.
Without a platform for horses to race we wouldn’t know how good the breed was and if we’re not breeding the best racers we’re not progressing the bloodline.
Furious at how obsured the article is, how conflicting and degrading it is – insult to anyone who has worked their life in racing.
Pathetic.November 29, 2011 at 22:17 #380241freeradicalMember
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Reducing the gene pool need not lead to unsoundness, but it will if it exposes a previously insignificant recessive disorder. It would be a surprise if there were no such recessive genes in the population but it is likely that their incidence is such that currently the vast majority of matings that involve a potentially ‘unfit gene’ would result in a heterzygous state with no or very limited significance.
The original article was rubbish, isolated breakages or some other feature is not evidence of inbreeding. Also comparing horse breeding with pedigree dog breeding is also ridiculous considering horses are breed for performance and not certain defined features that has nothing to do with fitness.November 29, 2011 at 23:42 #380260VenusianParticipant
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…I’ve been told some genes are more ‘dominant’ than other. Which genes
would be like this in horse breeding?
Coat colour provides us with good examples. Bay (including brown and black which are variants of same base colour) is dominant, while chestnut is recessive. The gene for grey, which overlays the base bay/chestnut colour, is dominant.November 30, 2011 at 09:19 #380280Eclipse FirstMember
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For the author to say inbreeding has become more prevalent in the last 40 years is farcical. He obviously has never heard of Marcel Boussac and how his experiments on inbreeding to Tourbillon ruined his studs. Coronation won the 1949 Arc by 6 lengths destroying a top class field by 6 lengths. She was inbred 2×2 to Tourbillon so his experiment could be said to have some success, yet when sent to the paddocks, she was unable to carry a foal to full gestation thus rendering her performances on the racecourse to a full stop.November 30, 2011 at 09:21 #380284TuffersMember
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steeplechasing; did you put a link up a while go about an owner who made a point of only buying horses from pedigrees that didn’t suffer from breathing problems? I kept meaning to re read it but then forgot which thread it was on. Found it very interesting. Thought Celtic Swing didn’t have very good conformation? We were at the National Stud in Ireland shortly after a Celtic Swing foal had been born. Wish I’d made a note of it, so I could’ve followed it’s career.
I would be interested in any stats on the soundness of the Byerley Turk line. As I understand it his line is the least represented in current sires (I think the Indian Ridge line was one of the last direct male lines of descent).November 30, 2011 at 09:52 #380287GodolphinArabianMember
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Champion racehorses are thoroughly inbred
All thoroughbred horses alive today are descended from 28 animals imported from the Near East during the 17th and 18th centuries.
Advances in genetics have allowed researchers to trace the ancestry of the world’s 500,000 thoroughbreds to three stallions and 25 mares.
Close to 95 per cent of all purely bred male horses can be traced back to a horse called Darley Arabian, born just over 300 years ago.
Researchers at the BA Festival of Science in Dublin yesterday described how new techniques for reading the genetic profiles of racehorses will increasingly allow trainers to screen out inherited diseases and ultimately to work out why some perform better.
Patrick Cunningham, professor of animal genetics at Trinity College, Dublin, said: "We have been breeding horses for centuries but the new genetics has something to say not just for mice and humans but for horses, too.
"New methods of reading DNA have allowed us to identify the common ancestors of today’s thoroughbreds.
"We are starting a new study to see how we can harness modern molecular methods to produce sounder, faster, better horses."
Prof Cunningham examined the genetic profiles of thoroughbreds alive today and found they were descended from only 28 horses. Ten of these accounted for 80 per cent of those alive today.
A horse that lived in the late 17th century called Tregonwell’s Natural Barb Mare was identified as an ancestor of 14 per cent of living female thoroughbreds.
Thoroughbreds cannot by definition be the offspring of non-thoroughbred horses, so the population is becoming progressively more in-bred.
Prof Cunningham said the proportion of genes shared by any two thoroughbreds had risen from 31 per cent two centuries ago to around 47 per cent now.
Work on the human gene map has identified 140 genes related to performance and fitness, although more are likely to be discovered.
Despite the physiological differences, these discoveries can be adapted for horses to examine areas of performance such as how muscle cells respond to the pressure at the end of a race.
Dr Emmeline Hill, of University College Dublin, said that with owners spending as much as £7 million on thoroughbreds, genetic information would be used to try to breed winners.
Stallions were imported to England in the 17th and 18th century for breeding.
telegraph.(2005)November 30, 2011 at 17:29 #380343Marginal ValueParticipant
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BBC Radio 4 produces a programme, More or Less, which explains to listeners how not to be fooled by politicians, newspapers, scientists, commercial organisations and anybody else who wants to mislead you with words and numbers. The author of this blog probably read the book (The Tiger That Isn’t) written by the programme’s presenters and thought "I wonder how many of those methods of misleading I can fit into one blog article". Nine paragraphs about thoroughbreds breaking legs alongside a scientific study of inbreeding, desite the data showing no link, is meant to leave an impression in the mind of the reader. Saying "As yet it isn’t possible to say whether Thoroughbreds are being bred to destruction." "As yet…" is a beautiful little phrase for the misleader. "As yet there is no evidence that Mr A N Other is a wife beater or drug addict". Even tabloid newspapres wouldn’t dare to use a phrase like that. Saying "And no-one wants to be watching the Derby, Kentucky Derby or Prix de l’Arc de Triomphe in 2018 and to see another horse fall, broken under its own weight and heritage". The use of the word "another" is direct a suggestion, unsupported by any evidence, that inbreeding has caused a horse to fall and break a leg in these famous races. It just leaves that impression in the mind of the reader. "Another" is a cheeky little word isn’t it? Does the BBC still have a reputation to maintain?
If there is a significant detriment to thoroughbreds caused by inbreeding, I cannot believe it would manifest itself in more broken legs. If Darwin’s theories still hold good, any genes that enhance the chance of winning more races would be confirmed (eg. higher bone density, strong ligaments, increased heart/lung capacity), and genes that have a negative effect on racing performance would be sidelined, (eg brittle bones, weak ligaments, bleeding lungs). But of course the bleeding lungs could be masked by drugs, which is why all thoroughbred racing countries are gradually moving towards a policy of no drugs, except within normal veterinary use.
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