Thursday, 9 April 2020

Did aurochs and wisent hybridize?

Hybridization is very common in the animal kingdom and takes place everywhere closely related species meet each other. There are plenty of examples where hybridization played a role in speciation, not only in amphibians and fish but also mammals, including us humans. For a post on hybridization, go here
In recent years, it has been suggested that the wisent is a species hybrid of aurochs and steppe bison because the wisent clusters with domestic cattle on mitochondrial level. For details, go here. This theory has recently been questioned by a 2016 paper that suggests the affiliation of wisent and cattle mitogenomes are more likely a result of incomplete lineage sorting. It also suggests an early split from the steppe bison, from which it differs in head orientation associated with food choice. While the American bison and Steppe bison have a lower head orientation than the wisent as they are primarly grazers, the wisent has a higher head orientation and is a mixed feeder, which is probably the result of living in a more forested habitat [1]. A 2017 study indeed suggests that Bison schoetensacki was the immediate ancestor of the wisent [2].  

However, the wisent does show signs of admixture with Bos in its nuclear genome [3]. The study compared both modern and pre-bottleneck wisents to cattle and the 8.000 year old British aurochs with the fully resolved genome and found signs of interbreeding with domestic cattle. The authors also emphasize that it is possible that these genes are not from domestic cattle but from aurochs closer to domestic cattle than the British aurochs. Either domestic cattle or aurochs or both left their track in the genome of the wisent. However, the very small portion of Bos DNA suggests that this introgression did not happen in recent times. Hybridization may indeed explain the diverging horn shapes sometimes found in wisent, like in this individual at Hellabrunn Zoo I photographed in 2011: 

It is important to note though that wisent and cattle do not interbreed spontaneously. Not a single case of hybridization between both species in the wild has been reported even if they share the same habitat [4]. All wisent-cattle hybrids were created in human custody. However, it might have happened that domestic cattle genes found their way into the wisent genome over those hybrids. If they escaped and joined wild wisent herds, they might have been more likely to interbreed than pure cattle. 
Another possibility would be that both species interbred more easily than today when aurochs arrived in Europe during the middle Pleistocene and later further diverged due to the so-called Wallace effect or reinforcement. In this case, hybrids between aurochs and wisent would have a lower evolutive fitness than pure individuals, thus decreasing the likelihood that both species interbreed. This is just a thought-experiment of mine. 
Another possibility if aurochs and wisent indeed interbred in the past could be that the influence from wisents helped the newly arriving aurochs, which migrated from subtropical areas, to cope with the European climate. I would not be surprised if the curly hair on the forehead that can also extend to the entire neck, dewlap and shoulders which are found in taurine cattle and European aurochs, were in fact vestiges of hybridization with wisents, as those curly hair is very opulent in bison but completely absent in zebus and other Bos cattle. 

Because of the fact that bison and Bos cattle can interbreed, some authors tend to list them all as one genus Bosin recent years. I tend not to. There are no objective measures to determine what is one genus or more than one, it entirely subjective just as all systematic ranks. Hybrids between genera are not that uncommon, for example in chicken, whales (see “Wholphin”) and there is even one case in elephants (see “Motty”). Paleonotological evidence suggests that bison descend from Leptobos, and genetic evidence also suggests that yaks are in fact part of the bison branch and might descend from Leptobos as well. Bos, on the other hand, might descend from Pelorovis. In this case it could well be that all Leptobos and Pelorovis species could interbreed with cattle and bison if they were alive today. Thus they would have to be included into Bos as well, making it an extremely variable super-genus based solely on the fact that they can interbred. And, to be consequent, other genera would have to be lumped as well. Pseudorca and Tursiops and all related genera would have to be listed as one genus, and one might even go that far to synonymize Loxodonta with Elephas. The ability to interbreed alone might not be the best criterion for synonymizing genera, especially as it is gradual from fully infertile offspring to only one sex being fertile to fully fertile offspring. 

Literature 

[1] Massilani et al.: Past climate changes, population dynamics and the origin of Bison in Europe. 2016.
[2] Palacio et al.: Genome data on the extinct Bison schoetensacki establish it as a sister species of the extant European bison. 2017.
[3] Wecek et al.: Complex admixture preceded and followed the extinction of wisent in the wild
[4] Vera: Do European bison and domestic cattle cross spontaneously? 2002. Vakblad Natuurbeheer 

Sunday, 5 April 2020

Resting aurochs bull portrait

The putative Pajuna crossbreed of the TaurOs Programme inspired me to do a portrait of a resting aurochs bull: 
The horn shape is based on a skull from Germany. Some might wonder why I tend to draw large-horned aurochs. This is simply because this horn size is very common in European aurochs bull fossils. But my next aurochs is going to be a short-horned individual like this one, I promise. 

Saturday, 4 April 2020

Breeding-back: How I would do it

In this article, I want to outline how I would execute “breeding-back” myself if I had the chance to breed a herd. There are multiple ways to Rome of course, and I am not saying that I would do it better than anyone else, it is just how I would do it. 

1. The goal

My goal would not be to breed yet another “breeding-back” herd, but to produce a high-quality line that is as genetically stable as possible even if genetic diversity has to be sacrificed. Of course genetic diversity is important, but the purpose would not be to fill the entire European continent with this herd exclusively, but to produce high-quality individuals that can improve the quality of other herds and therefore the gene pool of “breeding-back” cattle as a whole. This is similar to the line bred by Walter Frisch (the Wörth line), who produced a herd of Heck cattle with the best horns found in this breed, which are also comparably stable in inheritance, what contributed a lot to the improvement of horns in other Heck cattle herds. This was also achieved by the use of inbreeding in order to stabilize traits. 

2. The starting herd 

Of all the primitive breeds and “breeding-back” herds on this world, what would I compose my starting herd of? I would take a number of good Taurus cattle from the Lippeaue because I think they represent the top quality of contemporary “breeding-back”. I would select individuals that have the right colour, are large, have a good body shape and proportions and take care that the choice of individuals also includes genes for large and correctly curved horns. Maybe one or two Auerrind crossings with Watussi genes would be included as soon as they are available. This starting herd would include all genes for the desired traits that domestic cattle have: large size, aurochs-like proportions, aurochs-like horn curvature and dimensions, wildtype colour and sexual dimorphism. 

3. The breeding 

I would use a large chef bull that would cover all the cows. In order to speed up the process, I would not use the same individuals/generations for too long but instead replace them quickly with the subsequent generation. If the first filial generation has produced a good bull and good cows that are at least as good or better than their parents, I would sell the parental generation (or at least the chef bull), the offspring taking their place. In the subsequent generation, I would do the same and so on and so on. When selecting I would try to continuously increase the level of quality. Due to the inevitable (and in this case, wanted) use of siblings mating as well as selection, the gene pool would continuously narrow. The result would be a quality line that is comparably stable for the desired traits. It has worked with the Wörth line, it should also work with Taurus cattle. 

4. The selection 

Every breeder has his own priorities concerning selection criteria. I would pay a lot of attention to body shape, proportions and size because these traits are controlled by a large quantity of genes, surely dozens and possibly hundreds, while colour is regulated only by about a dozen of genes. I would also prioritize inwards-curving horns because they are comparably difficult to breed as this trait is rare in primitive cattle. Due to the use of Chianina, alleles for colour dilution might be present quite frequently in the population. I would try to eradicate those two or maybe three alleles, even if it might take a while as they are recessive. It has worked in the Neandertal and Wörth line, it should also work here. I would select against bulls with a colour saddle, as the European aurochs probably did not have this trait and it might be a sign of reduced colour dimorphism. However, I would not always select out black cows, as historic evidence reports the existence of black aurochs cows in Europe. For the horn size, we have quite a large spectrum indicated by fossil and subfossil bones. However, I would not permit horns that are only the size of Sayaguesa horns or smaller. Horn size is most likely regulated by a large number of genes, and it might be that genes for small and thin horns are sometimes recessive. In the Wörth lineage, small-horned individuals still might appear occasionally. Recessive alleles are very difficult to breed out and also requires luck. 

Breeding works with luck and by coincidence. One would need patience, especially when using the method as described in section 3. In the Lippeaue, many individuals are half-Sayaguesa. Half-Sayaguesa will always look good in some way because Sayaguesa is a very good breed. But it becomes more difficult when you mate crossbred individuals among each other, because inheritance works by chance. The result might have the large horns of Heck cattle, or the small body size. It might have the large size of Chianina and long legs, or the diluted colour. Londo, the Taurus bull, was the result of two siblings mating. He looked a lot like his father Lamarck, but was smaller and short-legged. However, due to its genotype there was the chance that he was more stable than its father (which is not stable at all as it is a cross), and indeed he seemingly passed on the short legs with stability. This shows that using siblings mating for stabilization can work quite fast. In the case of Londo it was simply bad luck that he was stable for short legs and not for his good traits. 


Friday, 3 April 2020

New photos of three Auerrind bulls

Claus Kropp recently released new photos of three Auerrind bulls on Facebook: 
From left to right: Sayaguesa x Grey, Maremmana x Watussi, Sayaguesa x Maremmana  © Claus Kropp
Grey cattle x Sayaguesa © Claus Kropp
Maremmana x Watussi © Claus Kropp
The Sayaguesa x Maremmana bull looks good, although it is impossible to predict what cattle will end up looking like before the age of 3 years. Its horns still have the grey protective layer, what means the horns can still grow quite a bit. The Grey cattle x Sayaguesa bull looks like an aurochs-coloured version of Grey cattle, with a bit more forwards-facing horns. The Maremmana x Watussi bull reminds me a lot of Heck bulls from the Wörth lineage, especially in terms of horn shape, except for the red colour and the zebu hump of course. 
I would cross those bulls with the Sayaguesa x Chianina cows, they would add alleles for large size, long legs and forward-facing horns. Or maybe also the Chianina x Watussi cow for more horn volume. 

Wednesday, 1 April 2020

The largest Taurus bull

How large are Taurus cattle? Several individuals have been measured. The first Taurus bull that was measured was Lucio, the first Heck x Sayaguesa bull. He was 160-165cm tall at the withers. This was the only measurement for a Taurus individual until I visited the Lippeaue in 2015. I took a yardstick with me and we measured a couple more individuals. Two cows were measured 153-155 cm at the shoulders, both cows had average size compared to the other individuals. The cow Larissa is noticeable larger than both, so that she might be 160cm tall at the withers. The bull Linnet is about the same size as Bionade (the cow measured 155cm at the withers), so he should be about 155cm tall as well. 
As for the largest bull on the site, 42 623, we have no direct measurement but an indirect one. When standing next to the large Sayaguesa cow Dona-Urraca, he almost dwarfed her, so we already knew that he has to be very tall. We then measured the distance between a metal bar of a cage that he was able to touch with his withers and the ground, so that we could infer his size. It was 173cm, so that the bull is at least 170cm tall at the withers. It is thus the largest Taurus bull measured, and the largest “breeding-back” bull in general. 
42 623, the largest Taurus bull (Sayaguesa x (Heck x Chianina)), photographed in the Lippeaue in 2017
170cm is a very satisfying size as it represents the average bull aurochs size for the Holocene according to van Vuure 2005. Also, it makes it bigger than most primitive cattle breeds. With these measurements, Margret Bunzel-Drüke and I concluded that the average size for Taurus bulls is between 150 and 170 cm, and for cows 150 cm, making Taurus cattle the largest cattle in Central Europe. Heck cattle are only 140-145 and 130-135cm tall, thus the attempt to achieve an aurochs-like size range by crossing-in large and very large breeds was successful. 

42 623 is a cross between Churro, the Sayaguesa bull, and Ludovica, a Heck x Chianina cow. 


Turf cattle

Recently I did a reconstruction of a turf cow based on a photo taken by Markus Bühler who presented it on his blog Bestiarium in 2012. 

Turf cattle are an extinct type of domestic cattle in Europe during the Neolithic. Domestic cattle in historic and prehistoric times tended to be much smaller than today, and turf cattle are a particularly drastic example for that. Their shoulder height was probably below one metre, making them as small as modern Dahomey cattle or even smaller. 
The gracile legs of the specimen are almost goat-like. The cow still has a small hump, so its body shape was not that derived as in most cattle today. 

There are no studies on their relationship to modern domestic cattle that I know of. It could be that they stand outside the modern domestic cattle family tree, or belonged to the same branch as modern European domestic cattle. The breeding associations for Braunvieh, Grauvieh and other alpine breeds claim their breeds descend from turf cattle, which is not based on any facts as far as I know. 

Hybridization with wild aurochs might explain the very small size of the smallest reported female aurochs with a withers height of only 112cm[1]. 

[1] Schibler et al.: Incorporation of aurochs into a cattle herd in Neolithic Europe: Single event or breeding?, 2014. 

Monday, 30 March 2020

Some more photos and videos of TaurOs cattle

It is not easy to find information on the TaurOs cattle herds. While doing google search I found a photo of a TaurOs bull in Keent, Netherlands. 
The bull looks much like a Pajuna, but the horns do not fit at all. They are much larger and upright than in Pajuna - maybe it's another cross with Maremmana, or a different type of cross. It is hard to guess based on the looks of the animal alone. Here are some cows from Keent. Based on colour and horn shape they might be Sayaguesa x Maremmana crosses, but could also be anything else. 

I also found two new videos of the herd at Milovice, Czech Republic. This video shows, additionally to the bull that looks a bit like a Texas longhorn, two new bulls (6:48). I don't know if they are descendants of the cows in the herd or if they have been moved to the herd recently. Based on their looks they might have Pajuna in their genes. The other video shows some atmospheric shots. 

Looking at the pictures and videos, horns protruding outwards or having a corkscrew-like shape are very common in TaurOs cattle, additionally to upright Maremmana-like horns. The goal should be horns facing forwards and inwards as in the aurochs. Of the breeds used in the project, Maronesa is the only one that has inwards-facing horns on a regular basis. So the horn shape of TaurOs cattle can be improved by producing a number of good Maronesa crosses with inwards-facing horns and using them as breeding bulls at their numerous breeding sites. Otherwise it might become rather difficult for the project to achieve aurochs-like horn shapes. 

Sunday, 29 March 2020

Two new aurochs drawings

Recently I did some new aurochs drawings, one of them is a reconstruction. 
This is a reconstruction of the 182cm tall Vig specimen, based on this photo. The Vig bull is the largest specimen on display. Its horns are more upright (somewhere between 80 and 90° to the snout) and less curved than usual in bulls. Looking at the reconstruction, a mix of Lidia, Chianina, Camargue and Watussi might be suitable to produce a convincing look-alike for this specimen. In case anyone is wondering where the eel stripe is, it would not be visible from this perspective. 
This is a portrait of a bull that is mainly based on the Sassenberg and Braunschweig bull specimen. 


Tuesday, 24 March 2020

Second-generation Auerrind calf born!

Today the Auerrind project announced that the first second-generation calf has been born. It is a bull and the son of the Chianina x Sayaguesa bull and the Maremmana x Watussi cow. 

It will be very interesting to see it grow up. It is completely open what it will look like as the chance that it has a trait of the four founding breeds is equally 25% for all breeds. 

Sunday, 22 March 2020

Aurochs cow colour schemes

While the colour of aurochs bulls is easy to determine (black or very, very dark brown), there is a larger spectrum for the possible colour of aurochs cows. Historic evidence indicates that there was variation, which is also in accordance with the colour of wildtype-coloured domestic cows. 

I tried to illustrate this variation on with a drawing. It shows an aurochs cow which is based on the Camebridge specimen in four different colours, representing the spectrum which is documented by cave paintings and the report from Schneeberger in Gesner 1602. They mainly differ in the degree of eumelanisation. Eumelanin is black pigment, and in wildtype coloured cattle black hair starts to grow on the sides of the trunk, legs, head and neck and continues to grow up to the top of the body, leaving only a dorsal stripe of a lighter colour. Wildtype coloured cattle can either be fully eumelanised (“bull colour”), not eumelanised at all or somewhere in between, depending on when this process stops.

Top left: This colour scheme is completely reddish brown with a dark eel stripe and dark forelocks, and having no black hair except for the tail tip. This colour scheme is similar to that of banteng cows and found in wildtype-coloured domestic cows (see here for a Taurus cow showing this colour). There are cave paintings which might show this variant. The other colour variants, or actually all wildtype coloured cattle, also have a dark eel stripe but reduced to a very fine line that is not always discernable. 

Top right: This is the “standard” colour scheme. Reddish brown with black or very dark brown head, neck, legs, sides of the trunk and tail tip. This colour is very common in wildtype-coloured domestic cattle and you can see it in this Heck cow. It is also illustrated in cave paintings and therefore was most likely present in wild aurochs. Some wildtype-coloured domestic cattle have dark brown hair instead of reddish brown hair, which can be seen in Maronesa cows or some Heck cows (I know of no cave painting that unambiguously shows this colour but it might have belonged to the natural variation of wild aurochs as well). 

Bottom left: This colour scheme is basically black with a reddish brown colour saddle. This colour variant has been illustrated in cave paintings and is nicely shown by the Taurus cow Lerida

Bottom right: “Bull colour”. Apparently, aurochs cows sometimes also had a colour identical to that of bulls. Cave paintings show a black cow and Schneeberger also reports this. This Taurus cow shows this colour. 

There is a continuum between those colour schemes. They represent a spectrum and all possible colours along this spectrum can be found in wildtype coloured domestic cattle, and probably also the aurochs. Apparently there was less selective pressure on the exact colour of aurochs cows so that we find this variation. 

That means that “breeding-back” has room for variation concerning which cow colours are to be permitted in breeding. Other, lighter, colours like beige or very light brown indicate dilution alleles (f.e. see this Taurus cow) and should be selected out as they are most likely domestic mutations. 

Wednesday, 18 March 2020

When to cull cattle selectively in a wild state?

The ultimate goal of breeding-back is to release the herds into nature, opposing them to natural selection so that they become dedomesticated wild animals after a sufficient amount of time. However, there is the problem that breeding-back herds are not genetically uniform and when artificial selection is stopped, their phenotype becomes increasingly heterogeneous in the starting phase. This is what happened to Heck cattle in Oostvaardersplassen. All possible phenotypes may appear. Therefore there is the question whether selective culling should be applied at the start of the dedomestication phase in order to assist natural selection to stabilize a wild animal-like phenotype and prevent very domestic phenotypes. 

Concerning adaptions necessary for survival, cattle and aurochs probably differ in a similar manner as wild and domestic yak. That means we can assume that in domestic cattle, aspects such as fat storage, digestion, metabolism, endurance and respiration are probably different from aurochs and less adapted for a survival in nature, leading to a higher death rate (this is what we see when comparing domestic to wild yaks), and perhaps this is true for other physiological aspects too. Natural selection prefers those individuals with the better genes for a survival in nature. Not to forget, we have intraspecific selection factors such as sexual selection and combat that will influence the cattle (predators, if present, can be a selection factor as well). These selection factors will prefer those individuals that have a higher chance for winning intraspecific fights and being chosen by mating partners, and therefore have a higher reproductive success. This can be caused by genes influencing behaviour traits and certain morphological traits. Not to forget, both factors are connected. Individuals with a more aware and active behaviour as much as the higher readiness to take risks will have a higher chance of winning fights and thus have a higher reproductive success. These behaviour traits are influenced by the corticosteroid hormones, which also influence morphology and are involved in producing the typical domestic morphology. Some individuals might have behaviour traits that are connected to hormonal levels that would enforce a wildtype like body conformation although they do not look “good” in overall appearance. We would have to acknowledge the fact that nature knows better concerning natural selection. 

What selective culling would do is mainly to remove individuals whose horns have the wrong shape or size or that have the wrong colour. This would, in turn, slow down the process of dedomestication as this could often also eliminate individuals that might have alleles for physiological traits advantageous for survival. We cannot know if an individual that has the wrong colour or small horns has alleles for better fat storage, metabolism or other “invisible” factors crucial for survival, or if it has a more wildtype like behaviour. Thus, selective culling based on such optical factors at the beginning of dedomestication would be counteractive. 
And there is the problem of balancing traits. Most people tend to overemphasize colour because it is the first and strongest impression. Yet it is only regulated by very few genes, while other aspects such as skeletal proportions, body shape and body size have a much more complicated background. For example, the Oostvaardersplassen herd has a bull that has a very aurochs-like morphology in build and shape like no other Heck bull has, it almost looks like a Spanish fighting bull. However, it has a grey colour and upright horns. I, personally, would never cull this individual as a lot of genes are involved in skeletal proportions and morphology but only one allele causes this kind of dilution. But someone else might consider this individual to be one of those with the “undesired traits” because of its grey colour and would cull it. 

Thus, my opinion is that breeding back cattle that have just been released into wilderness should not be culled selectively at all in the first decades. At first, the cattle would have to seize their genetic potential without disturbance by artificial selection in order to get dedomesticated and have a chance of survival that is as high as possible. They would have to have get uniform for the traits enforced by natural and sexual selection as quickly as possible and the result will undoubtedly be aurochs-like due to the regression to the wildtype, as wildtype traits (be it morphological, physiological or anything else) are more beneficial under natural circumstances as the wildtype is a product of nature. Relying on pleiotropic effects might also lead to some surprises just like in the Farm fox experiment, only in the opposite direction. For traits that would take longer to be influenced by natural selection, such as colour variants or horn shape, selective culling could be used after a few decades. But I, personally, would not cull selectively within the first thirty years of dedomestication. 

Saturday, 14 March 2020

Some questions and answers

This post is a kind of Q&A post with questions that I have been asked quite frequently or that simply might be interesting. Note that the answers to the questions represent my personal opinion or interpretations based on the sources that I have.

How many types of European wild horses do you think there were during the Holocene?
The common anecdote of a “forest tarpan” and a “steppe tarpan” is not based on reliable evidence. Rather, genetics suggest that there was a continuum from the Russian steppes to the Pyrenees, and the Iberian peninsular being a separate gene pool. Whether or not there were any morphological differences between these populations or within the continuum is not examined yet. So there is no hard evidence for different geographical horse types. Geologically, however, the populations changed over time according to newest genetic evidence. During the Pleistocene, dun horses were predominant while during the Holocene, black phenotypes became more dominant, which is probably related to the shift from an open to a forested habitat. 

When did the European wild horse die out?
This cannot be ascertained as multiple scenarios are possible. Either the genuine wild populations died out completely and were later replaced by feral horse populations in historic or prehistoric times, or there was a gradual shift by continuous depletion of the genuine wild population and intermixing with feral horses, so that the last free-ranging horses at the end of the 19th century were completely feral horses with no wild genes. It is also possible that they were hybrids or, perhaps less likely, still pure wild horses – there is simply not enough data for it.  

Why is there so much less on wild horses on the Breeding-back blog? 
Because there is much less to say. First of all, it is not certain when predomestic horses really died out in Europe, there is not a single articulated Holocene wild horse skeleton or at least a cranium that can be found anywhere, the true life appearance of wild horses as much as the historic sources are dubious and not to forget that the difference between wild horses and domestic horses is not as large as between aurochs and cattle. 

Your opinion on the word “Tarpan”? 
My opinion is that this word should not be used in order to avoid confusion. It was not a vernacular term for the European wild horse as often claimed, but rather a local term in the Russian steppes for the free-ranging horses, whatever these were (it is possible that they were feral domestic horses, caballine wild horses, caballine wild horses mixed with feral horses, Przewalski’s horses or Przewalski’s horses mixed with feral horses). The word “Tarpan” is also connected to the unsupported hypothesis of a “forest tarpan” and a “steppe tarpan” as much as myths such as the alleged origin of the Konik. It would be better to abandon the term overall, regardless its widespread use, and simply refer to predomestic horses in Europe as exactly that or simply European wild horses. 

What do you think about water buffaloes for Europe nature systems? 
I am aware of the ecological benefits of water buffaloes in the reserves where they have been used due to the turbation of small water bodies they make, but I don’t think that water buffaloes would be inevitably necessary in European ecosystems. The subfossil record does not document it unambiguously, also the evidence in Austria is dubious. However, I do think that water buffaloes that are suited to European climate would do no harm. A crossbreed of European domestic buffaloes and Asiatic wild buffaloes might be the best option for this job.  

Did the Heck brothers good work or not?
There is an extensive article on this question. I think we owe the Heck brothers something for inventing the idea of breeding-back. Without their initiative, there probably would be none of the projects or cattle that we have today. But yes, their work was sloppy to a certain degree and could have been done better with the possibilities back then, f.e. they could have done more precise research on the actual morphology of the aurochs, they could have made a herd book and more strict selection criteria. And of course, claiming their heterogeneous breeding result with its only vague resemblance to the aurochs is a revived aurochs was a-zoological. 

Hybridization with living wild bovines for “breeding-back” yes or no? 
I tend to say “no” to this idea. It would make breeding back results species hybrids, what would make the academic and public acceptance for the breeding back results even more difficult. However, a small-scale project crossing wild yaks with breeding back results could be interesting and might also be beneficial for the survival rate of the cattle during winter, as wild yaks are way better adapted to surviving cold winters than domestic cattle. 

Which cattle breed that is currently not used would you like to see being used in breeding-back? 
Quite a lot: Maltese, Chillingham, Corriente, Florida Cracker, Turano-Mongolian breeds, Camargue and others. They would add diversity to the gene pool, and have many beneficial traits; Camargue and Maltese have a very slender morphology, Corriente look very good in general, Chillingham and Turano-mongolian cattle are very hardy and suited to cold climate. 

Will the aurochs ever return in its original form? 
As the full genome of one British aurochs bull from the early Holocene has been completely resolved, it is possible – one way would be to edit the genome of a cattle individual with CRISPR-Cas9 and replace the domestic alleles with aurochs alleles and let a large domestic surrogate mother carry the aurochs calf. It would be interesting to see how far epigenetics and “junk” DNA will influence the development of the individual. I wrote an article on what to do with a living aurochs. 

Which is the best breeding-back project? 
I think there is no fair way just to pick one project or breed. All the current projects have advantages. For example, the Auerrind project has really good quality founder individuals and is experimenting with interesting combinations. The Tauros Programme has quantity, they gained areas and herds rather quickly and now they have to breed for quality individuals. Taurus cattle has both considerable quantity (about 100 individuals in the Lippeaue and 400 in Hortobagy alone) and a lot of high quality individuals that are on the top of what “breeding-back” has achieved so far (Lamarck, Lerida, and other Taurus individuals). It would be most beneficial in my opinion if the three major projects would cooperate, and it seems like this is going to happen some time in some form. One large metapopulation of the best breeding-back cattle available would be an ideal scenario. The resulting cattle could simply be summed up under the umbrella term “breeding-back cattle” or “aurochs-like cattle”. 

Which “breeding-back” herd currently has the best animals? 
In my opinion, definitely the Lippeaue Taurus cattle herd in Soest, Germany. Not because it is the herd that I know best but simply it has a lot of quality animals to offer which have not been surpassed or equalled in other herds yet – Lamarck, Lerida, 42 623, Loxia, Lambretta and many others. In Hortobagy, Hungary, there might be some individuals of a similar quality but I do not know those herds thoroughly enough. 

Which one do you consider the most aurochs-like breed? 
This is a question that is very hard to answer. It also depends on what level you compare the cattle. But, as all factors of a living organism are interconnected, most cattle that have a less-derived anatomy also have less derived behaviour and survival capacity. Actually I think the Iberian fighting bull, Lidia, is one of the least-derived cattle breeds on this world. It is one of the very few cattle breeds that truly has a wild cattle-like morphology despite being small and often having too short legs. Its morphology and behaviour suggests to me that its “domestication syndrome” is not as intense as in many other breeds. There are people who do not consider it aurochs-like because of its exaggerated aggression level, but the tame and docile nature of other breeds is not aurochs-like either. The aurochs was probably in between. A breed that I also consider very aurochs-like, but not in the same way, is Maronesa. It is the only primitive breed that has a well-pronounced inwards curve in the horns and a flawless colour setting with, most importantly, a well-marked sexual dimorphism. This breed is, however, short-legged (bulls) and of small body size. Corriente is also a very aurochs-like breed overall, but small as well. The Maltese ox is remarkable for being large, long-legged and long-snouted but the horns are meagre. After all, all breeds have their pro’s and con’s, but I would say that these four are on the top of those breeds that I am aware of. Lidia, however, sticks out to me for the overall very primitive appearance and morphology. 

Saying that Maronesa or Lidia, for example, are very aurochs-like, would you expect those breeds also to be genetically closer to the aurochs than derived breeds? 
Yes, I think it would show in the genetics to some degree. But I still think that the aurochs is so far removed from all living domestic cattle that the difference might not be that noticeable. It should not be forgotten that there are eight millennia of domestication, a rather dramatic process concerning the genetic structure, are between aurochs and cattle, regardless of local hybridization. 

Is recreating the aurochs by selective breeding possible? 
As I explained in a number of recent posts (for a summary, go here), I do not think it is possible to recreate the aurochs by selective breeding with modern domestic cattle. Domestic cattle are too remote (both in evolutional and organismic matter) from their wild ancestor, the domestication process was probably too intense and domestic cattle are too derived so that a lot of the original gene material of the wildtype was probably lost during this process that is lasting for eight millennia now. 

Can we call breeding-back results “new aurochs”?
I think that we should not call any cattle “new aurochs”. It is true that aurochs of the 21st century would differ a little bit from those of the 16th century, just as those of the 16th century differed slightly from those of the late Pleistocene, but domestic cattle bred for optical resemblance would still be a huge step apart from all geological and geographical variants of the predomestic wild aurochs. Calling domestic cattle a new aurochs just provokes associations with the overly simplistic negligence of the Heck brothers, who indeed thought they had revived the aurochs just by crossing a couple of cattle breeds. It also gives the wrong impression that whenever a wild animal disappears, we can “breed it back” anytime anyway. 
Only a totally dedomesticated strain of aurochs-like cattle would be something that I would call a postdomestic wildtype, just as the aurochs was the predomestic wildtype, but I would not call them aurochs, as it is zoological consensus that “aurochs” refers to the predomestic wildtype of cattle. 

What do you think on the relationship of the quagga and the “Rau quagga”? 
I covered this issue in this post. To me, the Rau zebras are normal plains zebras that have been selected for a reduced stripe pattern while the quagga apparently was more distinct – although this topic is perhaps understudied. Regardless of whether it was a distinct subspecies, a geographical cline or just a colour variant, the Rau Zebras share only a superficial resemblance with the Quagga due to the reduced stripe pattern. While the reduction of stripe pattern in Rau zebras is impressive, it is not completely identical to that of the Quagga, and on a genetic basis, the Rau zebras have nothing to do with the Quagga. In the same way Burchell’s zebras would not suddenly become Grant’s zebras when bred for a more extreme stripe pattern, or Timber wolves would not end up as polar wolves when bred for an exclusively white phenotype. Therefore, I think the Rau zebras should not be called “Rau quaggas” as they are not any more related to the quagga in any sense than other Burchell’s zebras. 

If I would do a breeding project, what would it be like? 
I have so many ideas. For once, I would like to try the combination Maronesa x Chianina/Maltese and supplement it cautiously with few doses of Watussi for horn volume. Or, in order to increase genetic diversity in “breeding-back” start a project working with breeds never used in “breeding-back” before, also including Turano-Mongolian breeds (see this post) or Chillingham cattle and Corriente.. It would also be interesting to breed a herd of the best Lidia individuals which resemble the aurochs to a large extent, and supplying them with breeds that add size (f.e. Chianina, Maltese) and horn volume (Watussi, for example). 
Very tempting to me is the idea to take herd of good “breeding-back” results and select them for wildtype-like behaviour (shyness, low agreeableness, more extreme fight/flight reaction) and to see if the morphology also reverts back to a more wildtype-like condition (this idea would be a reverse experiment the Farm fox experiment and has been introduced in this post). 
Also, it has been an idea of mine to breed an aurochs-like zebu herd (see here). 
Selective breeding with horses for a strong stripe pattern would be to see how far selective breeding can drive the stripe pattern in horses would be interesting as well. 
Apart from “breeding-back” herds, what I would really like is to carry out a project that creates a large and healthy wisent herd that was supplemented by cautious hybridization/introgression from American bison as described in this post. 

If I would want to start a breeding herd now, which where would I take the cattle from? 
I would take some good individuals from the Lippeaue plus perhaps some good and promising Auerrind crosses, and would maybe add one or two individuals from breeds not yet used in breeding back, such as Chillingham or Corriente. This is the composition I would take if I want a larger breeding-back herd. If I’d like to breed on a smaller basis for a line focusing on quality only, I would simply take some good Lippeaue Taurus cattle and try to breed them for maximum quality.

If one extinct species could be reconstructed with genetic methods, which one would be of your preference?
Most resources are concentrating on the woolly mammoth at the moment, and I think this is a good choice – the woolly mammoth is spectacular, popular and important enough to be the first extinct species brought back to life. It would also be my whish that the Tasmanian tiger or moas could be recreated, although this is probably impossible due to the lack of genetic information and suitable surrogate animals. And of course, genetically recreated aurochs would also be very delightful. 

Which one is the most wild horse-like: Konik, Exmoor, Sorraia, Dülmen or others? 
In my opinion, none of them is particularly close to the European wild horse. In the case of the Dülmen pony, it is evident that the modern population is a mix of mostly northern ponies and the Konik, and there is no evidence that the original population from the medieval times were true wild horses. For the other three breeds, genetic tests never unambiguously showed a special status for any of those breeds, and the breed history for both the Konik and the Sorraia shows that it was bred using rural horses, and it also seems that the modern Exmoor pony is an invention of the 20th century. 
If any of those breeds would indeed descend from one of the last remaining wild horse populations, it would definitely show in the genetics; they would be quite set apart from European domestic horses. Also, their documented breed history evidences otherwise as well. Furthermore, their phenotype does not match up. Most recent genetic evidence suggests that Holocene wild horses were mostly of a black phenotype, while none of those breeds above are of that colour. 

Are zebu and taurine cattle different species? 
I think there is definitely no good reason to classify zebuine cattle and taurine cattle as separate species. Surely they are phenotypically far removed from each other, but that is due to artificial selection. Indian and European aurochs, the “natural” state of both clades, were probably not so far removed from each other. There are some gametic processes that show incipient speciation, but subspecies are always incipient species. It is purely a matter of taxonomy that has no relevance for the actual science, but zebuine and taurine cattle and therefore also European and Indian aurochs should be listed as one species in my opinion. 

Heck cattle is a good or bad “breeding-back” breed? 
Heck cattle of course does not meet the initial goal of phenotypically replicating the aurochs, far from it. However, it is an extremely heterogeneous population. While some herds, especially those in zoos and private farms that experienced little selective breeding, are barely useful for breeding back, there are many herds nowadays that are a pretty good basis to work with. Especially regarding the horns, as many of the better Heck cattle have horns that are very good in terms of dimensions and OK in terms of curvature, thanks to lineages such as the Neandertal herd or Walter Frisch’s former herd in Wörth/Steinberg. Not to forget, Heck cattle always have a very good winter coat and are well-suited to Central European climate, which is useful when crossbreeding with southern breeds. 

Was original Europe one big forest or a grassland savannah? 
I believe that as so often, the truth probably was between both extremes. For once, I think the theory that the natural state without any human interference would be forest in Europe is flawed by the fact that we have many indicator species for open land that were present in Europe’s interglacials long before humans arrived, so Europe could not have been just one big forest. Furthermore, bovines were shown to have been pretty common game in the subfossil record, and I do not believe that forest alone would have provided enough suitable space for such large populations to dwell. However, it seems that palinological evidence shows that Europe was not one big grassland, and the faunal utopia of aurochs, wisent, water buffalo, elks, wild horses, Equus hydruntinus and other large game present all over Europe is not backed up by the subfossil evidence either. For example, the European wild horse was much less common in the Holocene than in the Pleistocene, and the record for water buffaloes is dubious. There is solid evidence for wild ass in parts of Austria, but as far as I know only in Austria. Europe probably was not such a large game paradise as Africa, but neither was it a closed canopy forest. Considering that this continent is very multifaceted geologically and geographically, I think it probably was a mosaic of closed, semi-open and open landscapes. 


Tuesday, 25 February 2020

The Taurus-Heck continuum

Taurus cattle can either be regarded as a separate breed or as a Heck cattle variety. I like to regard Taurus cattle as an advanced Heck cattle variety because of the breeding history (taking good Heck cattle and supplementing them with suited breeds in order to improve their aurochs-likeness), and because there is a continuum between Heck cattle and Taurus cattle. The Lippeaue cattle is surely most advanced as the Heck cattle percentage is lowest there (as low as 25%), but there are other herds which have a higher portion from the stem breed and, more importantly, there are many Heck herds that have influence from Taurus cattle, as more and more Heck cattle breeders incorporate Taurus individuals into their herds because they are larger and look better. So that there is a continuum between both cattle types. Because of that, the 2009 Weideleitfaden of the ABU states that it will probably be impossible to differentiate between Heck and Taurus cattle on the long-term sight (as Taurus cattle have more aurochs characteristics than Heck cattle, this is a good thing of course). It is my impression that the Taurus percentage in the Heck cattle population in general is rising and becomes more widespread.

While doing google searches, I came across a bull that shows this phenomenon perfectly. It is the breeding bull at the Steveraue in Olfen, Germany. It is unquestionably a Heck bull, but it has Taurus characteristics such as having more forwards-facing horns, a higher hump and is higher on the legs than old-school Heck bulls. 


Sunday, 16 February 2020

Behaviour selection - a new perspective for breeding-back?

Most „breeding-back“ projects do select on behaviour in some way. Individuals that are too aggressive, or too nervous and explosively behaving, are getting culled in all projects because they are too difficult and dangerous to work with. A question that came up in my mind while researching on the connections between behaviour and morphology is if a project that selects on wildtype-like behaviour would be capable of reversing some typically domestic changes in morphology and other aspects that traditional breeding-back cannot. 

Behaviour is interconnected with a number of other organismic traits as outlined in a number of posts (go here), what also shows in a connection between tame behaviour and morphological changes associated with domestication (see the Farm fox experiment). Selection exclusively on tameness produces most of the typical symptoms of the domestication syndrome, f.e. reduced brain volume, neoteny, piebald colour and other morphological changes because of developmental cascades and pleiotropic effects. So tame and neotenic behaviour goes hand in hand with a domestic morphology. Domestic cattle have been selected on docility and agreeableness for millennia. The Iberian fighting bull (Lidia), on the other hand, is the cattle breed that has the most aurochs-like (or: least derived) morphology, and is also the least tame breed as it was selected on agility and aggression and not tame and agreeable behaviour. This of course provokes the question whether this is a coincidence or not; did the Spanish fighting bull keep its aurochs-like morphology because it was never selected on tameness, but on aggression instead? This has been outlined in the post The looks vs. behaviour problem and the Spanish fighting bull (the fact that Lidia are allowed to fight for mating rights alone cannot explain their aurochs-like morphology, as this is also true for other breeds that do not have an aurochs-like morphology such as Eringer or Chillingham cattle).  
And an even more interesting question: would domestic cattle that are selected on wildtype behaviour traits (important: not necessarily aggression) also redevelop an aurochs-like morphology? 

The latter question could be highly relevant. While modern breeding-back has produced a number of very beautiful results with good horns, size and colour, none of them has a morphology as aurochs-like as in good Lidia bulls, and have a morphology and skull shape that reveals they are domestic cattle. If selection on wildtype behaviour could indeed reverse the processes and cascades that develop the domestic morphology we see and perhaps even more, the results could be more aurochs-like than anything else after a sufficient amount of time. A project selecting aurochs-like cattle for wildtype behaviour might be worth a try. 

It is important to note that cattle behaviour towards humans also depends a lot on socialization and not only genetics. If raised under natural circumstances and treated the same, you could probably also fight with a Holstein bull, while you could probably also milk a Lidia cow if raised in a barn with a lot of human contact. But there are genetic differences regarding the potential behaviour spectrum the cattle will show. For example, Lidia has of course a much more extreme fight/flight reaction than Highland cattle, and most if not all cattle will be in between. 

Crossbred populations of course show a mosaic of possible behaviours, and so do “breeding-back” herds. For example, individuals of breed combinations without any Lidia in the mix showed the same nervous behaviour as most of the Lidia crosses, while some Lidia crosses were as relaxed as non-Lidia individuals. As all of them are raised in the same population under the same circumstances, the chance is high that this has a genetic background. But not only the behaviour towards humans when being handled or flight distance is relevant, but the whole behavioural spectrum. Heck cattle, being a mix of derived and less-derived cattle breeds, is also heterogeneous on behaviour aspects such as calving. While most Heck cows calve outside the herd near a shelter as most bovid species do, some calve in the herd, which is a domestic condition. 

Selection on wildtype behaviour

By selection on wildtype behaviour I do not mean aggression/nervousness, and not the behaviour towards humans alone, but the whole set of behavioural nuances. This would include flight distance (we do not know what the flight distance of wild aurochs was, but you probably would not have been able to approach and stroke them), stress response, agility, awareness (not nervousness), calving in a shelter, herding behaviour, and other aspects. Individuals that are too tame could be selected out, as well as cows that calve in midst of the herd or do not show herding behaviour. Stress response and agility could be tested in a manner similar to how it is tested in Lidia cattle, where riders ride in the herd and tease the individuals with sticks. Not that the most aggressive individuals would be favoured, but rather those that behave and move apathetic would be selected out. 

Selection on stress response, awareness and agility would certainly influence the production of corticosteroids and perhaps even thyroid hormones, what itself would probably influence the development and morphology of the animals. It could be seen as a true reversal of the selective pressure that led to domestication, as selection on tameness affected the production of exactly these hormones, what probably also caused the typical domestic morphology. 

The question is which cattle to take for such a project. I would select good individuals of breeding-back projects in order to achieve a basic similarity with the aurochs right from the beginning, and because they are mixed populations and thus have a wider spectrum of different behaviours than purebred herds. 

How to handle these cattle 

For such a project it would probably not be possible to handle the cattle the way they are handled in grazing projects. As I wrote above, many cattle in grazing projects are slaughtered because they are too difficult to handle and a project selecting on wildtype behaviour would probably produce a lot of such. It would be best to keep the cattle the way Lidia or bison are kept, also concerning the equipment. In the end, a wild aurochs would also be much more difficult to handle than domestic cattle (and even the best breeding back cattle are still domestic cattle). Also, it probably has a reason why most grazing projects use cattle and not wisents. 

The perspective 

The goal of the project would be to see if a selection on wildtype behaviour would indeed also lead to a more wildtype-like morphology due to the hormonal and developmental cascades that caused them in the first place when cattle were domesticated. It would, basically, be the reverse to the famous Farm fox project and with another species. Probably the cattle would be more active and agile, and if their body changes they might indeed develop longer legs plus a slenderer, more athletic and muscular body. Perhaps even other effects of domestication such as paedomorphy, which influence the skull shape and horn growth, might become reduced. 
It is just an idea, but in my opinion an idea that is really worth testing. 




Friday, 14 February 2020

A Taurus steer in Hortobagy, Hungary

Steers can be very interesting to look at as they differ in morphology from functional bulls. They grow taller, have longer legs, longer horns and a longer snout. Therefore, they are more aurochs-like in these respects. One possible explanation might be that castration reduces the effect of the developmental delay caused by domestication that results in the morphology we see. So the horns continue to grow when they would stop growing in a functional bull, and so also other parts of the skeleton. You see that very clearly in Chianina steers, which have considerably longer horns than functional bulls of the breed. Thus, the horns of domestic bulls which are almost always shorter and less curved than in the aurochs, even in aurochs-like breeds, might be another symptom of so-called paedomorphy. 

The morphology of steers is a very strong hint that development contributes a lot to the typical domestic cattle morphology, and not mutated novel alleles for the actual traits alone. Altering the developmental processes and timing will result in the domestic phenotype, reversing these changes might let the aurochs phenotype surface again (for the trait looked at). It is therefore always interesting to look at steers and compare them with functional bulls of the same breed. 

In Hortobagy, where they have the largest Taurus cattle breeding site with about 400 individuals, they also have bull herds. Some of these bulls are castrated. I have seen couple of photos of Taurus steers before, and recently I discovered a photo online. Go here for the photo. 

The hump is well-expressed, the colour and the head look like those of a cow. As the degree of melanisation in the fur is linked to testosterone level in E+ cattle, the steer does not have enough testosterone to develop the black colour of bulls and therefore it retained the reddish brown colour scheme of a cow. Castrated banteng bulls show the same phenomenon (van Vuure, 2005). The horns grew much longer than in functional Taurus bulls and thus are more strongly curved. Not as curved and inwards-facing as in aurochs, but more so than in functional Taurus bulls. 

It is particularly interesting to look at the horns of steers, as they reveal the genetic potential for horn growth and curvature that functional bulls of the breed have. While in functional individuals the horns might only be shaped like bananas, they actually might have the genetic potential for an aurochs-like horn curve if they were not stopped to grow by development. 

This, in turn, has implications for “breeding-back”. It means that selective breeding on the actual horn shape might not be that effective, because the “error” does not lie in the horn genetics of the animal, but rather the developmental calibration of the whole organism. The insufficient horn curvature is thus a symptom of the basic domestic nature of the animal, which is even harder to reverse by selective breeding. As long the animals are domestic, their horns will stop growing earlier than in an aurochs and thus are shorter and less curved. 
However, some Lidia and Maronesa bulls happen to have an aurochs-like horn shape despite being domestic and displaying other domestic traits.