Any studies out there? If a cribber s 100% controlled (collar, hotwire, cribox, surgery, etc) so her foal never sees the behavior, what are the odds he will do it purely from genetics?
Jennifer
I donāt know about āpurely from geneticsā in the situation you describe, but I had a mare that didnāt crib, I bred her to a stallion that didnāt crib and yet their colt became a cribber very early on. He was never around any other horses that cribbed; he just started doing it. Perhaps a grandsire or granddam was a cribber and passed it down genetically.
Anecdotallyā¦I have a broodmare whoās a cribber. She doesnāt wear a collar, lives outside in a 50 acre field with a dozen other mares and foals approximately 18 hours a day (depending on the season) and is in a stall the remaining time. She has had two foals for me. Both had ample opportunity to watch her crib, but so far neither has picked up the habit (oldest foal is 20 mo. old, younger is a 8 month old weanling). Both foals were raised on the same, mostly outside, schedule, and both were more interested in hanging with their buddies than they were in staying next to a fence so they could crib.
Iāve never heard of cribbing being genetic - itās something that is either learned or starts due to environmental conditions that foster the behavior.
Edit: apparently there have been a fair amount of statistical studies that support an increased prevalence of cribbing in certain populations - namely thoroughbreds and geldings and stallions. No one has tested this experimentally (which is likely due to the difficulties inherent in such research), though apparently thereās a specific gene locus that may be culpable. As in all things genetic, that only enhances your predisposition to a phenotype - environmental factors determine whether or not the genotype will be expressed. As in many scientific arenas, lay articles tend to extrapolate and exaggerated beyond the actual science, so read everything with a sense of caution.
To answer the OPās question: the specific statistical odds ratio depends on many factors (breed, sex, husbandry conditions). But, youāre probably asking colloquially how likely it is, and the answer is really not very likely, even if all the conditions line up perfectly.
I wholeheartedly believe there is a genetic link, but itās not as simple as Mendelian inheritance from what Iāve seen. I think the predisposition has a genetic link; but itās a crapshoot whether or not itās triggered. Because Iāve known cribbing broodmares who both did and did not pass the trait along. Iāve also known horses out of non-cribbing parentage who started. But if the horse is not physiologically/genetically predisposed to cribbing, they wonāt develop the habit period.
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It has been WELL proven that cribbing isnāt learned behavior.
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I have a mare that cribbed when in a stall - outside, she is fine. None of her babies have ever cribbed. I know a study of 1 mare isnāt a heck of a study, but she did have 7 or 8 foals. Iāve never heard of any study of the genetic inheritance of cribbing (or many other āvicesā).
I just stumbled upon this recent study on cribbing ā might be a selenium issue along with a zinc factor. Interesting.
http://www.sciencedirect.com/science/article/pii/S1558787817301776
Interesting. Thanks for sharing.
My one question after reading that is if there is a link between Se and Zn levels and cribbing, what physiologically causes the fluctuation in levels?
Dietary alone does not seem like it could induce the behavior. If so, it would be easier to pinpoint or predict cribbing. For example, farms with poor nutrition or mineral deficiency should see a disproportionate number of cribbers developing. Yet only <5% of horses exhibit the behavior, with some fluctuations apparent by breed. For example, several studies cite increased incidence in Thoroughbreds, yet interestingly, very little incidence in Standardbreds, who are managed similarly.
A cursory google search brought up 2 interesting links:
http://animalscience2.ucdavis.edu/ang105/References/Behavior/genetics%20of%20behavior.pdf
Marsden and Henderson (1994) noted that in a study with Prezwalkskiās horses, a horse had a 25% chance of displaying a stereotypy if their grandparents or siblings had a stereotypy, but the chance rose to 60% if either of the parents showed stereotypic behavior.
Waud et al. (2012) reported a common gene locus in cribbers within two breeds. However, I didnāt download the whole paper.
I think itās entirely plausible that some heritable problem with Se and Zn management impacts cribbing and other stereotypiesāsay, some problem in Se and Zn storage or transport within the cell or across the cell membrane? Will be interesting to see further research!
Interestingly, my cribber seems to have a much higher dietary requirement for copper and zinc. Iāve never tested her Se or supplemented (Iāve always been in high Se areas) but perhaps it would be prudent given this researchā¦
Simkie, interesting, Iāve never read anything to that effect. So, as a scientist who studies learning & behavior (not horse behavior, admittedly!) I was curious and did some research, and there does appear to be a hereditary component (so I stand corrected!). But, the evidence is pretty weak given the time this subject has been under investigation and the tools we have to research this today, so the genetic component should be taken with a grain of salt. I think Texarkana is probably on the right track - the hereditary component is probably quite complex, and the commencement and continuation of the behavior requires certainly environmental factors to come together. As in most everything, it is almost certainly a bit of both. Importantly, it almost certainly involves a component of learned behavior, but I suspect the distinction is that Iām not suggesting its learned by observational learning, which is admittedly pretty rare in adult horses. But it is almost certainly learned from trial and error learning - you do it once, you like the way it makes you feel, so you keep doing it. Thatās learning. An action can have both a hereditary and learning component, so the two are not mutually exclusive.
In case anyoneās interested, hereās a summary of a quick 90 min search I did:
The main paper that keeps being referenced by most lay-person and scientific articles is the one by Albright et al. 2009 (attached). Here, they discuss cribbing and conclude its most prevalent among thoroughbreds. But, if you read the paper, they donāt appear to test whether in thoroughbreds it is a genetic component, they just collect data and attest that itās most prevalent among thoroughbreds, which as a breed, present a substantial confounding factor (i.e., many have a history of track life which could be a common etiology of the behavior). Thereās also the Vecchiotti and Galanti (1986) article (below), which goes a bit further and says that thereās a pattern among thoroughbred lines, but their methods seem a little dubious by todayās standards (i.e., they ask trainers which horses crib, and just trace back the lines asking āhow many horses in subject Xās lineage also cribbed?ā; likely completely appropriate for a 1986 short communication though, which are typically papers that say āhey, we found this! We donāt really know what it means, but wanted to get it off our chest and publish it asapā).
Bachman et al (2003) shows the most convincing evidence for it being most prevalent among thoroughbreds and warmbloods, but this was in a surprisingly narrow sample size of horses in Switzerland. Again, though, having a higher odds ratio may mean that its hereditary, but hardly confirms it (i.e., this was not tested explicitly, and there could be a confound or two).
In a very recent review on the subject (Wickens & Heleski 2010; below), the Albright and Galanti papers are literally the only two papers cited as showing support for the idea that cribbing may have a hereditary component, which I think is not terribly convincing for a question that was raised several decades ago. Since this hypothesis has been put forward as early as the 80ās (maybe even as early as the 50s by a Japanese group), Iām a little surprised no one has actually done more to identify the genetic components involved (or maybe they have, and they havenāt found any positive results that are publishable - another case where null findings should be published, but thatās another story).
In conclusion, it looks like cribbing may have a hereditary component, but a lot more research needs to be done before Iād go so far as to say itās not learned. I think itās also important to separate whether itās learned by observing others or just learned as a method of coping with certain stimuli (i.e., trial and error). I think itās pretty unusual for adult horses to learn behaviors simply from watching other horses (letās face it, theyāre just not that smart as far as animal intelligence goes), but they do learn behaviors from their own experience (i.e., if I crib when Iām in my stall, I feel better because Iām not bored, or whatever). Finally, itās 100% completely possible for it to have a hereditary component and a learning component - you may have a genetic predisposition to crib, but the act of it is reinforcing, so you do it again --> i.e., itās learned.
Long story short, I guess itās obvious in retrospect that it may have a hereditary component - stereotypies frequently do - but I donāt know that science is ready to say itās 100% hereditary and not learned (via trial and error learning). What needs to be done is 1) a meta-analysis of all of these self-report data, 2) a GWAS study where they look for common genomic factors in cribbers, and 3) a manipulation where they knock out or knock in, or activate/inactivate such an allele/factors and eliminate/increase the behavior in a rodent model, respectively (obviously such a study is a long way away, but manipulating the behavior via manipulation of a genetic component would be the necessary science to conclude that itās more hereditary versus learned).
Albright et al. 2009:
http://onlinelibrary.wiley.com/doi/10.2746/042516409X372584/full
Vecchiotti and Galanti 1986:
http://www.sciencedirect.com/scienceā¦01622686900989
Bachman et al. 2003:
http://onlinelibrary.wiley.com/doi/10.2746/042516403776114216/epdf
Wickens & Heleski 2010:
http://www.sciencedirect.com/scienceā¦002029#bib0355
I also just wanted to add that Iām not trying to tear down the science - as a scientist, I appreciate that no study is perfect. But itās important for the public and laypersons not to incorrectly extrapolate the science. These articles are all pretty careful to suggest that there may be a hereditary component, and not fully suggest that the behavior is genetic.
I also want to add that Iām not trying to argue with anyone - I legitimately learned something today, and Iām happy for that! And I also think this science is in its very early days, and thereās a lot more to be done before we really know the extent to which genetic factors control the behavior. Also please take all this with a grain of salt - this was a pretty cursory search on my part, and Iām not an expert in this field!
If anyone has any other articles with stronger causal evidence, Iād love to see it!
To answer the OPās initial question, based on these papers, very low chances if environmental conditions donāt support it (discussed in the papers I linked - Iād start with the Wickens & Heleski review).
Really? Iād be curious to see the evidence. I donāt mean observational learning, I mean trial and error - i.e., you try cribbing, and you like how it makes you feel (relieves boredom, etc.) so you do it again. Thatās learning. Iād be interested to see how a study would test and eliminate learning as a source of the behavior.
Besides, even if it is genetic, almost certainly itās not an on/off situation (i.e., you have the gene and you crib, you donāt have it and you donāt). Thereās almost certainly an environmental component that supports learning about the behavior; i.e., the horse experiments and finds it pleasurable (as is the case with most behaviors with a genetic component).
(Iām not trying to argue here, just curious about this as the science I found from a quick 90 min search is not terribly convincing.)
Sure. Start here. This is the first google hit. Thereās a ton more out there. This has been studied extensively.
http://www.thehorse.com/articles/23939/cribbing-not-a-learned-behavior-researchers-say
The peer reviewed paper is linked at the end of the article.
Since you seem to think itās learned, can you provide peer reviewed published studies that prove that?
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@Simkie , so that article again discusses observational learning (i.e., mimicry, āafter exposure to another cribberā), which is not what Iām talking about. Iām talking simply learning to do a behavior by trial and error - does that distinction make sense? I agree that itās pretty clear that itās not due to observational learning. However, there are other types of learning such as instrumental: you try something once, you like the results, so you continue. Thatās learning. Learned behaviors can also have a hereditary or genetic component, the two are not mutually exclusive. In fact, most behaviors with a genetic component also require learning - you have a genetic predisposition to be addicted to smoking, but you have to learn the behavior first - it doesnāt arise and maintain itself out of thin air, and addiction doesnāt start the first time you smoke. You like how it makes you feel, so you keep doing it. Thatās learning.
Also, I canāt imagine anyone has explicitly tested whether itās due to learning - I canāt imagine how youād design such a study. But theories of instrumental learning would suggest that it is - you do something, you like how it makes you feel, so you do it again (this can also have a hereditary/genetic component).
(I just want to add that Iām not trying to be argumentative, I just find this particularly interesting, especially given how the lay articles seem to extrapolate beyond that actual scientific findings.)
Also, the Albright paper cited in this article doesnāt actually test that itās hereditary. Their objectives:
- breed prevalence of crib-biting in US horses;
- the likelihood that one horse learns to crib-bite from another;
- and owner perceptions of causal factors.
So,
- seems more prevalent in thoroughbreds, according to two papers I found (albright & Bachman paper, discussed below). Thoroughbreds present a huge confound, given a common theme of track life at some point or another. Another paper (bachman, below) shows it may be more prevalent in Warmbloods, which is more convincing (especially given that many WB lines have TB in them at some point)
- we (science) have determined thatās itās almost certainly not observational learning (i.e., mimicry).
- I donāt think anyone here is interested in this.
As a scientist who studies the neuroscience of learning & behavior (not genetics, and not horse behavior, admittedly!) I was curious and did some research, and there does appear to be a hereditary component (today I learned!). But, the evidence is pretty weak given the time this subject has been under investigation and the tools we have to research this today, so the genetic component should be taken with a grain of salt. I think Texarkana is probably on the right track - the hereditary component is probably quite complex, and the commencement and continuation of the behavior requires certainly environmental factors to come together. As in most everything, it is almost certainly a bit of both. Importantly, it almost certainly involves a component of learned behavior, but I suspect the distinction is that Iām not suggesting its learned by observational learning (mimicry), which is admittedly pretty rare in adult horses. But it is almost certainly learned from trial and error learning - you do it once, you like the way it makes you feel, so you keep doing it. Thatās learning. An action can have both a hereditary and learning component, the two are not mutually exclusive.
From a cursory search of primary scientific articles, I think the science is pretty clear that there may be a genetic causal link, but thereās not actually a lot of strong evidence to that effect beyond statistical regressive methods. Most lay person articles cite the Albright paper, but they just look at prevalence among various breeds (specifically thoroughbreds, discussed above). What needs to be done scientifically to say that itās 100% controlled by genetics is 1) a meta-analysis of all of these self-report data, 2) a GWAS study where they look for common genomic factors in cribbers, and 3) a manipulation where they knock out or knock in, or activate/inactivate such an allele/factors and eliminate/increase the behavior in a rodent model, respectively (obviously such a study is a long way away, but manipulating the behavior via manipulation of a genetic component would be the necessary science to conclude that itās more hereditary versus learned).
A specific identified genetic component would be a good start - someone else mentioned a Waud 2012 paper, but I canāt find it. Iāll believe that thereās a genetic component, though, so that would be pretty good evidence.
Alternatively, this chapter discusses thatās it may be learned, but that its more likely contingent on an interplay of genetic and learned factors (which is usually the right answer when discussing genetic etiology of behavior):
https://www.paardenwelzijnscheck.nl/ā¦ereotypies.pdf
This review discusses that itās susceptible to punishment, which suggests it has a learning component (if you learn it, you can unlearn it): http://onlinelibrary.wiley.com/doi/1ā¦tb05143.x/epdf
Most lay articles repeatedly cite a few papers, which are only survey & statistical (how many horses crib, what breed or lines are they, etc.), not experimental.
In case anyoneās interested, hereās a summary of a quick search I did:
The main paper that keeps being referenced by most lay-person and scientific articles is the one by Albright et al. 2009 (attached). Here, they discuss cribbing and conclude its most prevalent among thoroughbreds. But, if you read the paper, they donāt appear to test whether in thoroughbreds it is a genetic component, they just collect data and attest that itās most prevalent among thoroughbreds, which as a breed, present a substantial confounding factor (i.e., many have a history of track life which could be a common etiology of the behavior). Thereās also the Vecchiotti and Galanti (1986) article (below) which is cited a lot, which goes a bit further and says that thereās a pattern among thoroughbred lines, but their methods seem a little dubious by todayās standards (i.e., they ask trainers which horses crib, and just trace back the lines asking āhow many horses in subject Xās lineage also cribbed?ā; likely completely appropriate for a 1986 short communication though, which are typically papers that say āhey, we found this! We donāt really know what it means, but wanted to get it off our chest and publish it asapā). Would have been great to take blood samples of all those lines to actually try and identify the common genetic component, but hopefully someone is working on that now?
Bachman et al (2003) shows the most convincing evidence for it being most prevalent among thoroughbreds and warmbloods, but this was in a surprisingly narrow sample size of horses in Switzerland. Again, though, having a higher odds ratio may mean that its hereditary, but hardly confirms it (i.e., this was not tested explicitly).
In a very recent review on the subject (Wickens & Heleski 2010; below), the Albright and Galanti papers are literally the only two papers cited as showing support for the idea that cribbing may have a hereditary component, which I think is not terribly convincing for a question that was raised several decades ago. Since this hypothesis has been put forward as early as the 80ās (maybe even as early as the 50s by a Japanese group), Iām a little surprised no one has actually done more to identify the genetic components involved (or maybe they have, and they havenāt found any positive results that are publishable - another case where null findings should be published, but thatās another story). (Except for the Moab article, which I canāt find. But I also didnāt see it cited anywhere else, which is strange given itās 2017, almost 2018 now.)
In conclusion, it looks like cribbing may have a hereditary component, but a lot more research needs to be done before Iād go so far as to say itās not learned. I think itās also important to separate whether itās learned by observing others or just learned as a method of coping with certain stimuli (i.e., trial and error). I think itās pretty unusual for adult horses to learn behaviors simply from watching other horses (letās face it, theyāre just not that smart as far as animal intelligence goes), but they do learn behaviors from their own experience (i.e., if I crib when Iām in my stall, I feel better because Iām not bored, or whatever). Finally, itās 100% completely possible for it to have a hereditary component and a learning component - you may have a genetic predisposition to crib, but the act of it is reinforcing, so you do it again --> i.e., itās learned.
Albright et al. 2009:
http://onlinelibrary.wiley.com/doi/1...09X372584/full
Vecchiotti and Galanti 1986:
http://www.sciencedirect.com/science...01622686900989
Bachman et al. 2003:
http://onlinelibrary.wiley.com/doi/1...776114216/epdf
Wickens & Heleski 2010:
http://www.sciencedirect.com/science...002029#bib0355
I also just wanted to add that Iām not trying to tear down the science - as a scientist, I appreciate that no study is perfect. But itās important for the public and laypersons not to incorrectly extrapolate the science. These articles are all pretty careful to suggest that there may be a hereditary component, and not fully suggest that the behavior is genetic (though the lay person articles tend to have headlines like "cribbing is genetic!, which is not accurately reflective of the findings.) So, while there are a solid handful of articles discussing the genetic components of this and other stereotyped behaviors, itās a complex issue - the horse still has to do it once, realize he likes it (consciously or not) and keep doing it. What the science will probably find is that there is a genetic predisposition to crib, but that is just what it is - a predisposition (letās call it XX factor). There are probably horses without whatever XX factor that crib, and those with the XX factor donāt - because environmental factors also play a role. A horse with XX factor that never tries the behavior will likely never crib, because they wonāt have learned that its rewarding. (And I say all this because this is the story that repeats itself over and over in science - itās always seems to be a combination of genes + environment. I could well be wrong in this case, though!)
I also want to add that Iām not trying to argue with anyone - I legitimately learned something today, and Iām happy for that! And I also think this science is in its early days, and thereās a lot more to be done before we really know the extent to which genetic factors control the behavior. Also please take all this with a grain of salt - this was a pretty cursory search on my part, and Iām not an expert in this field!
(As an aside, as a scientist, I think itās important to clarify that science doesnāt PROVE anything - we can build support for a hypothesis, but you canāt prove it - your hypothesis may have strong support, but the right evidence can disprove it anytime. You can DISPROVE a hypothesis, though, which is the beauty of science.)
To answer the OPās initial question, based on these papers, very low chances if environmental conditions donāt support it (discussed in the papers I linked - Iād start with the Wickens & Heleski review).
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Itās all but proven that itās not a learned behavior, and that there is an inherited (genetic) component. They just donāt know which gene it is, and itās likely a combination.
The real JB lived for many years in a barn that has a cribber and weaver, 1 or both of whom were always in his sight, if not stalled next to him. This setup was 2-4 hours of turnout a day, the rest spend in their stall unless worked or otherwise taken out (ie hand grazing).
JB never even thought about either of those stereotypies.
At any given time, there were at least 4-6 horses who were either beside or in easy eyesight of these cribbing/weaving horses. Nobody else ever developed the behaviors. Granted, the sample size was relatively small, but in terms of 15-20 horses over the 20 or so years I was there, to me that becomes fairly significant.
The theory that itās likely a multi-gene trait, possibly recessive, means it isnāt something that is a certainty, ie if 1 parent has it, a foal will do it, if no parent has these behaviors, no offspring will have them.
There are MANY horses who live with stereotypie horses who never develop them. There are many individuals who live with non-stereotypie horses who DO develop one (or more). Itās complicated, definitely not black and white, yes or not, 1s and 0s.
Enough studies have been done showing a much higher prevalence in familial lines, relative to the overall population, to all but prove the genetic component. The rest is trigger-/environmental-based, and that brings with it the temperament of the individuals.
@Feathered_Feet you are using the word ālearnā differently than probably 100% of horse people when talking about cribbing. I donāt think anyone is talking about the dynamics of ālearning to do a behavior by trial and error.ā Ask any horse person if cribbing is ālearnedā and they will all respond on their belief as to whether or not cribbing is learned by one horse watching another and adopting the behavior. If you say ācribbing is a learned behavior,ā I think 100% of horse people will translate that as ācribbing is a behavior learned by one horse watching another cribāāand the responses you receive to that statement will be as you have seen here in this thread (or flipped, people agreeing with you, because there sure is a large contingent out there that thinks one cribbing horse will get the whole barn doing it.)
As to whether or not cribbing is ālearning to do a behavior by trial and errorā? What are the other options? Is it possible to ascertain between that and trial and error in equines? And why does it matter?
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@Simkie I think youāre 100% right. Since this is my professional field, I guess I use these words differently and very carefully!
I guess thatās what Iām trying to say though - there are some things that are purely genetic - Downās syndrome, for instance (genetic, but not heritable). Doesnāt require any learning on oneās part to start - itās all genetic. An example of something that is purely learned and not heritable would be a horse learning to open a gate - through instrumental, trial and error processes, a horse can learn to do that unguided, and itās not a heritable trait (intelligence may be, but thatās a different story). Drug and substance addiction, on the other hand, is more like cribbing it seems - thereās a clear genetic component, but thereās an environmental and learned component as well - you donāt just develop addiction out of nowhere. You have to try, and learn that it satisfies some unmet need.
āAs to whether or not cribbing is ālearning to do a behavior by trial and errorā? What are the other options? Is it possible to ascertain between that and trial and error in equines? And why does it matter?ā
The other options are that itās innate. A baby crying when upset is a behavior that is innate (but it is also later learned or unlearned!). So is laughing, or smiling when youāre happyā¦ but there arenāt a lot of other examples. Which is I guess why I was so shocked that so many denied that its learned - the overwhelming majority of behavior has a learned component. The key is that learned does not equal mimicry! (Which, again, we cleared up is due to my very specific use of the word learned!)
Anyway, hopefully the OP doesnāt worry too much - sounds like the risk for her particular situation is probably pretty small 
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There is a saying with many diseases that have a genetic link but are not āgenetic disordersā specifically:
āGenetics load the gun, environmental conditions pull the trigger.ā
Iād put cribbing under that category.
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Sadly not the case. One of my weanlings has been cribbing since he was a few months old, despite a Miracle Collar on his mom. Have NEVER had a young horse crib in nearly 20 years, but I have never bred a mare that cribbed either (i despise cribbong, but she is a really nice mare otherwise). Just wondering how big a mistake rebreeding her wasā¦ This colt may be going to get cribbing surgery as he is (like mom) a classic winduscking type cribberā¦
Jennifer
As I think we all agree, ālearning to open a gateā (and other similar actions) does follow a deductive path. Horse sees human fiddling with latch ā horse sees gate open after fiddling ā horse puts two and two together ā horse fiddles with latch, gate opens. Smart horse.
Another example: One of my geldings years ago learned that if he put his head through a particular section of post and rail fence (to graze outside the fence) that the middle rail would fall out on one side and he could reach even more grass. Eventually he learned that both sides of the rail would fall out if he reached far enough ā and that he could step through the hole and be free to graze outside the pasture. Soon he was knocking that rail out on purpose ā not accidentaly.
But itās hard to imagine that cribbing would follow this same deductive or accidental reward reasoning becauseā¦
ā¦ cribbing involves such a specific physical action ā acute straining ā for the reward to be had. In other words, the horse doesnāt get a little bit of reward by a little bit of biting on a fence. Horse has to fully crib.
I suppose the only way to truly know how cribbing happens, is to be there when a horse cribs for the very first time ā and to have been watching that same horse in the days prior. If someone was able to study that, then weād all know a lot more.
