Wednesday, 23 August 2017

The Indian aurochs III

In 2013 and 2015 respectively, I did posts on the Indian aurochs, Bos primigenius namadicus, the wild predecessor of zebuine cattle, each time supported by an artistic reconstruction I made for the subspecies.
However, in this post I want to start from a new and go systematically over what we know about this divergent subspecies and what it might have been like. Bos primigenius namadicus is very enigmatic – based on current evidence, survived until 8.000 years ago at maximum, and there are no unambiguous artistic references and of course no literary references to the wildtype of the zebu.

Before we dive medias in res, I want to define some expressions: when I use the term “taurine clade”, I do not refer to taurine cattle exclusively, but all animals that are on the branch of taurine cattle since the branches of taurine and zebuine cattle diverged, so also B. p. africanus and B. p. primigenius of course. The same goes with “zebuine clade”, it includes also B. p. namadicus. The namadicus-clade is therefore synonymous with the zebuine clade, and the primigenius-africanus clade with the taurine clade (note that I am talking about clades).

Phylogenetic evidence

While B. p. primigenius and B. p. africanus were pretty much alike, seems as if the Indian aurochs was a kind of the “weirdo” of the species, and its descendants, zebus, are still the weirdoes among cattle. Part of the reason might be that the namadicus-clade split up from the primigenius-africanus clade rather early about 1,7-2 million years ago [1]. That is more than one million years earlier than the oldest remains that have been assigned to Bos primigenius [2]. That is ten times the time distance between the domestic horse and Przewalski’s horse [3]. One might ask why listing them as part of one species then, and indeed the use of zebus as a species separate from that of taurine cattle is widespread. However, taurine cattle and zebuine cattle still hybridize readily without any problems, what supports classifying them and of course all their ancestors back to their point of divergence 1,7-2mya as one species. It is my preference to refer to this species as Bos primigenius. Nevertheless, meiotic chromosome pairing abnormalities in zebuine x taurine hybrids suggest that postzygotic isolation mechanisms were starting to develop, what suggests a beginning state of speciation [1]. But subspecies are always “incipient species”, as already noted by Darwin more than 150 years ago. As taxonomy is often subjective and species definition is a very tricky issue (I have been planning to do a post on that topic for a while), the differences might be enough for some to regard the members of the taurine clade (and therefore also B.p. primigenius and B. p. africanus) and the zebuine clade (and therefore also B. p. namadicus) as separate species. In this case, the Indian aurochs would be no aurochs, but you could still call the species like this, since it is its Indian sister species. An alternative suggestion that I have would be wild zebu for the wildtype. You can still use the term wild zebu if you consider namadicus an aurochs subspecies.

So it seems that the ancestors of Bos primigenius namadicus migrated pretty early from Africa to India, while the common ancestors of the primigenius-africanus clade stayed in Africa for another while. This early divergence alone probably might explain a part of the differences we see between namadicus and other aurochs populations.

Ecology

If the Indian aurochs was ecologically similar to other wild members of the species, it would have preferred semi-open landscapes near rivers and floodplains. In India, it was sympatric with gaurs and water buffalo, and their respective ecological niches supports this idea: gaurs prefer to live in more forested areas, and water buffalo prefer more wet habitats. Therefore, we would see niche partitioning between the three bovine species if the Indian aurochs was ecologically comparable to the other two aurochs subspecies. Modern zebus often are adapted to very arid habitats, but that is probably a consequence of the fact that they are the cattle of people living in very arid regions. So this does not necessarily indicate that namadicus was particularly adapted to arid habitats.

Morphology and external appearance

The morphology and life appearance of Bos primigenius namadicus is not very well known. In contrast to B. p. primigenius, where we have plenty of well preserved, more or less complete material, we only have fragmentary postcranial material and a few skulls for the Indian subspecies (van Vuure, 2005). In order to resolve what namadicus’ life appearance was like, we have three sources of evidence and clues:
- Direct evidence
- Parsimony based on phylogenetic bracketing
- Zebuine traits that might be wildtype traits of namadicus
Now let us have a look at what we can deduce for the life appearance of B. primigenius namadicus, the Indian aurochs or wild zebu if you will.

Direct evidence:
Direct evidence is what the bone material tells us. We have no unambiguous artistic references to namadicus (this rock art might or might not show an Indian aurochs; the horn tip might be tufted to it could also be a Kouprey). So we have to rely solely on the scarce bone material.
It seems that the Indian aurochs was smaller than the European subspecies. I was unable to find measurement data in the literature. I remember that Cis van Vuure mentioned that the size of one Indian cranium was comparable to that of an European aurochs cow. So perhaps 150-160cm is reasonable for bulls of the Indian subspecies, which was the lower size end for European aurochs bulls.

This is the only illustration of bone material from namadicus that I was able to find. I will refer to it as the Lydekker skull. It is not clear which sex it is; its eye sockets are not nearly as expressed as in European aurochs bulls, and it is narrow in build. This does not necessarily imply it is a female skull. Perhaps bulls of namadicus had a narrower skull with less prominent eye sockets. We cannot say yet (at least I cannot, having seen only this one skull). The drawing also does not enable to tell the exact orientation of the horns relative to the skull, but it is apparent that they face more upwards and less inwards than in many European skulls. The literature says that the horns of the Indian subspecies were larger in proportion and more wide-ranging than in European aurochs. Considering that basal aurochs and basal members of Bos (such as B. acutifrons, B. buiaensis) had very large horns, it would perhaps be more correct to say the horns of the Indian aurochs never shrank down, while some single Northern European aurochs had horns that were not necessarily what I understand as “large” (see here, for example). What definitely changed as namadicus diverged was the orientation of the horns. Basal aurochs had horns at a rather sharp angle (45° in the case of the oldest cranium), inherited from its ancestors. The horns of the Indian aurochs were definitely more upright. This might have been a result of genetic drift. So being proportionally large, wide-ranging and comparably upright, the horns of the Indian subspecies might have resembled those of Heck cattle of the Wörth lineage (see here, for example) and a number of Watussi albeit not that huge. This analogue also fits the Lydekker skull.
This is all that we can say based on osteological evidence.

- Parsimony based on phylogenetic bracketing
This is a way of reasoning that enables us to deduce traits that namadicus must have had even if we have no direct evidence for it. When both its direct descendants (zebus) and closest relatives (taurine cattle, the other two aurochs subspecies, other Bos, Bison or buffaloes) show a specific trait, it is almost certain that namadicus had it as well because it is the most parsimonious and therefore most likely assumption. For example, almost all wild bovines show a more or less slanted pelvis that we also find in zebus. So it is very likely that the Indian aurochs also had a slanted pelvis creating a rounded rear (perhaps not that extreme as in some zebus). A more horizontal pelvis seems to be an autapomorphy of the taurine clade that might have originated in Bos primigenius primigenius or the common ancestor of  africanus and primigenius already, and probably was also transferred to the wisent by hybridization (the wisent seems to be a hybrid species of Eurasian aurochs and Bison priscus [4]).
Very likely the Indian aurochs was a long-legged animal with a square-like build. It is a common trait in wild bovines and zebus also often are comparably long-legged (or actually short-trunked compared to derived taurine cattle). Most likely the Indian aurochs also possessed the high processus spinosi in the shoulder region for large muscles to attach – a universal, functional trait for wild bovines and evident in each single skeleton of Eurasian aurochs. The size of this hump (not to be confused with the zebuine hump, I’ll come back to that later) might have been different in namadicus, it might have been larger or smaller. One would have to look at the relative length of those processes if some are preserved.
Zebuine cattle have the same E+ allele that is also found in taurine cattle causing wildtype colour, so it very likely was the base colour for the Indian aurochs as well: lightly coloured muzzle ring and dorsal stripe, degree of Eumelanin dependent on testosterone level. Probably the colour was very similar to the European aurochs, but not totally. The allele(?s) that regulate the distribution of the pigment in the coat seem to have diverged a bit in zebus. For example, in taurine cattle the snout is strongly melanised all the way down to the muzzle ring, creating a sharp edge for the muzzle ring. In zebus there is more like a smoothtransition. In the less eumelanised individuals you do not see a saddle like in taurine cattle, but a light area on the lateral side of the trunk that looks similar to the saddle though. I call it the lateral zebu saddle. So there are subtle differences that might have been inherited from namadicus as a result of the long time of divergence. Furthermore, there are some zebuine colour modifiers as well, but we are going to look at these in the next section.
Very likely the Indian aurochs also showed a strongly marked sexual dimorphism. Sexual dimorphism is universal to all other members of Bos (at least in the species whose life appearance is known), although the dichromatism is quite reduced in most gaur populations. It is the result of the social and mating system of large bovines (harem system), and I have not heard of any differences in zebus on this aspect. So it is very likely that namadicus also had a strongly marked sexual dimorphism.

- Zebuine traits that might be wildtype traits of namadicus
Zebuine cattle have a lot of quite characteristic traits, and it is possible that some of them might be in fact inherited from their wild ancestors. This suspicion is especially strong if these traits are universal among zebus or at least very common. These traits include:
- the fleshy zebuine hump
- hanging ears
- zebuine colour modifiers
- the large dewlap

However, prevalence in the domestic population of the modern zebu alone is not an argument for its presence in the Indian aurochs. The abundance of these traits can also be explained if it appeared directly after domestication, was preferred by artificial selection or became fixated by genetic drift. But if those traits apparently serve a functional purpose, especially if this purpose would have been advantageous for the Indian aurochs, we can speculate that they are in fact wildtype traits.
The fleshy zebuine hump, however, seems to serve no purpose for the animals. It is formed by a hypertrophied Musculus rhomboideous and does not influence food storage or thermoregulation [5]. It might actually be of disadvantage for the animals because male zebus lack the big muscular neck bulge that is typical of taurine bulls and many other large bovines as a consequence of the altered neck musculature. Farmers use the hump of zebus to attach the plough on their shoulders, so the zebuine hump might have been a mutation that was preferred by farmers and is thus prevalent in zebuine cattle now.
Many zebus have large, hanging ears. Hanging ears are, in various shapes, a typical trait of domestic mammals of any species, so it was probably not a feature of the Indian aurochs. We cannot rule out that its ears were a little bit lowered compared to other bovines, but if so probably only to a shallow extent like in this individual but not huge hanging ears like this cow has.

As for the zebuine colour modifiers, it becomes a little bit more complicated. The Agouti allele that causes red pigmentation to disappear and creates a grey colour is very widespread among zebuine cattle, and I think it originated in the zebuine clade. Zebuine cattle introgressed a lot into Steppe cattle which originated in the west of the Eurasian steppe6, and the vestiges of zebuine introgression are very apparent in their looks (upright horns, large dewlap). Probably the Agouti mutation found its way into Steppe cattle by introgression from zebus. Steppe cattle further influenced many other cattle such as those on the Balkans, Italy and the Alps. The Central European breed Grauvieh shows the same Agouti mutation, and it even found its way until the primitive Iberian breed Tudanca. The Agouti mutation is likely a zebuine allele, but is it a wildtype legacy of Bos primigenius namadicus?
It is not entirely impossible. Colour does not have such a great impact on evolutionary fitness in large animals as in smaller animals, and genetic drift often play a role as well, so it could well be plausible that the greyish colour of zebus (i.e. the lack of red pigment caused by the respective Agouti allele) originated in namadicus. But considering that it was a tropical bovine, I think it is less likely; tropical animals often tend to be more melanised than those of temperate regions (Gloger’s rule; however, one has to be careful with the so-called ecogeographical rules; I am planning to do a post on that as well), and other tropical bovines and bovids show very vivid colours as well. So I tend to think the Agouti dilution allele is a mutation that occurred after domestication. One would have to test this locus on aDNA of B. p. namadicus (which would be very difficult to acquire because of the preservation circumstances in India).

Authors also describe the so-called “zebu tipping gene” that causes a light colour on the ventral side of the body (van Vuure, 2005). But I wonder if this is truly confirmed to be an additional locus in zebuine cattle (and since Bantengs also show very light areas between the legs, it could also be a basal gene that was lost again in the taurine branch), or if the light ventral hairs we see in zebuine cattle are just caused by an allele on a locus that is shared with taurine cattle, since wildtype coloured taurine cattle also often have light areas between the legs. It is actually part of this colour scheme, but to a varying extent. In this case, we can only guess whether it was present in namadicus or not. The same goes for the lateral zebu saddle for bulls.
Another trait that is often displayed by zebus are white ocular rings. Ocular rings in the adult stage are widespread among bovids, and in taurine cattle it is found in many calves but often lost in adulthood. It is very common in wildtype coloured zebu cows (also in taurine cows having the Agouti dilution; it is a stable trait in Tudanca cows), but rarely also found in bulls, such as in this miniature zebu bull from Germany (photo by Markus Bühler):
The bull at the right has a plausible colour scheme for Indian aurochs
(photo: Markus Bühler)
However, miniature zebus might be prone to display juvenile traits, what might be the reason for this bull having ocular rings. Here once again we can only speculate if adult Indian aurochs had ocular rings, and if only the cows had them or even the bulls as well. A colour scheme like that one shown by the bull encountered by Markus Bühler looks really aesthetic to me, it also has the lateral saddle and the lightly coloured ventral side, and also looks very credible for a tropical bovid. But we cannot know.

The large dewlap is another typical, universal zebuine trait. Eurasian aurochs evidently had a short dewlap, and according to stone engravings that of African aurochs was short as well. Nevertheless, I do not rule out that the Indian aurochs was the subspecies with the largest dewlap, at least for bulls. It is a general rule that bovids/bovines in tropical climates tend to have large dewlaps for display and perhaps also thermoregulation, while it is counteracting in temperate climates (heat loss), which is why bovids/bovines in temperate climates tend to have furry ornaments like beards or manes. So the dewlap of the Indian aurochs might have been actually a little longer, perhaps comparable to that of gaurs, bantengs and koupreys and was later exaggerated in zebus. It could have also been as long as in zebus. We cannot know because do not have unambiguous art that could give us a clue. I like to restore B. p. namadicus with a dewlap that is comparable to the related bovines I just named.

Interestingly, while the European aurochs reportedly had frizzy forelocks which are found in many taurine breeds, no zebu has this trait. This matches with the assumption that furry ornaments are a characteristic of bovids in temperate climates (additionally to that, I have the little suspicion that the curly forelocks might be a consequence of bison introgression into European/Eurasian aurochs; we know that aurochs and bison hybridized, it must not have happened exclusively in one way).

All in all, the picture we have of the Indian aurochs is not that frustratingly incomplete as the bone material we have because we can infer some things; we know that it was smaller in overall size but had large and wide-ranging horns that were a bit more upright, it probably had a typical morphology of a wild bovine and thus was comparable to the other two aurochs subspecies, it probably had a similar base colour and sexual dimorphism but we have to be unsure about some details of its colour or the length of the dewlap.
Taking all that into account, I created this new reconstruction of a bull and a cow (I was, surprisingly, inspired by this photo of two English longhorns for perspective and stance). I decided to do two versions: one showing a bull with the zebuine lateral saddle and one without.

Using zebuine cattle in breeding-back

In the previous posts on the Indian aurochs, I suggested doing a “breeding-back” project with zebuine cattle. Looking at modern zebus, it is apparent that there are seemingly no truly primitive zebus left that resemble their ancestor to a large degree. This could be the result of genetic bottlenecks or very strong artificial selection. But it should be possible to select on traits that we know or can infer with a high degree of certainty. I suggest a mix of Watussi (for the horns), miniature zebus with taurine influence as few as possible (for the colour) and autochthonous Indian zebus like Guzerat/Krankeji, Kenkatha and Javari. It should be possible to fully reconstruct the horns of namadicus especially with the aid of Watussi, to get the right colour scheme also with some degree of sexual dichromatism, and a square-shaped build. Obvious domestic traits like overly hanging ears or a hanging spine should be avoided.
I did a photo manipulation by copying suitable Watussi horns on a photo manipulation by Jochen Ackermann on Wikimedia commons he did using a Taurus bull and a zebu:

That is what I envision such a “breeding-back zebu” to look like. For some aspects, such as the presence of the lateral saddle, no strict standards should be set, because we do not know about their presence in the wildtype. The funny thing is, I came up with the idea of a zebu “breeding-back” project in a dream were I saw zebus that looked exactly like the photo manipulation above back in 2011. Such a project should best be carried out in India so that the animals are automatically suited ecologically. Releasing them on a sufficiently large area size and leaving them exposed to natural selection will certainly alter their morphology in a way that could provide us some clues on the wildtype. Their morphology would become more like those of wild bovines, their horn shape might become refined, and perhaps even the zebuine hump might disappear after some generations if it really serves no purpose to the animals. It would be very interesting to watch that.

But this section is also about using cattle with zebuine influence in existing “breeding-back” projects focusing on European aurochs. It is controversial and especially focusing on the use of Watussi. I see that in my comment sections and also forum discussions. People often have objections against cattle with zebuine influence because the zebuine clade diverged a very long time ago, zebus have a pretty divergent morphology, and are adapted to arid and hot climate – not what is needed in Central or Northern Europe. Those are good reasons to be averse to cattle with zebuine influence in “breeding-back” projects for the European aurochs, but now I am going to explain my point of view to this subject very clearly.
First of all, and most important to note, the fact that they belong to a clade that diverged long time ago per se does not imply cattle from this lineage have to be destructive. Actually, if the Indian aurochs was still extant but the European one extinct, I would use it in “breeding-back” projects at any time in order to get beneficial wildtype traits.
Zebuine cattle have a very derived morphology, that is true. But for “breeding-back” projects, I do not care if an undesired allele is of zebuine or taurine domestic origin, because it is undesired in any case. The recessive Agouti allele, that is widespread in any “breeding-back” project/breed, is not desired for the European aurochs, no matter if it originated in taurine cattle, zebuine cattle, or even the Indian aurochs – so it makes no difference. The zebuine hump is not desired for the European aurochs, in the same way the overly long hair of Highland cattle or the virtual lack of sexual dichromatism in Sayaguesa is not desired for the European aurochs – again, it makes no difference on which clade this mutation originated because it is not desired in the population anyway.
The next and very important point is that whatever undesired trait you introduce to the population, you can breed it out again. The fact that zebuine cattle are adapted to hot and arid climate, and therefore have a short and less dense coat and less subcutaneous fat does not mean that using zebuine cattle will result in all crossed cattle being less well adapted to cold and wet environments but the traits are going to split up in the second cross generation and you have to pick the right individuals – just as with any undesired and desired traits. Steppe cattle, for example, are heavily influenced by zebuine cattle yet they are among the cattle that are best-suited to cold habitats and have a supreme winter coat, which is why they are used in all “breeding-back” projects. It not only depends on what you crossbreed, but also on what you select for.

The amount of desired vs. undesired traits of course implicates how to use a breed. To give an example, I take the Watussi crossbreeds in the National Park Hortobagy. I was told that second-generation crosses with Watussi influence often turn out unsatisfying. This is not surprising: Watussi have a number of undesired traits (zebuine hump, zebuine body, large dewlap) versus one desirable trait (horn size). So the likelihood for a second-generation cross to end up disappointing is larger than for it ending up pleasant. But that does not mean that Watussi is not a good choice for breeding, not at all. It means that the breed has to be used a bit more cautiously than breeds with a lot of desired traits and that one has to be a bit more patient and lucky to get really good second-generation crosses.

It is rare that Heck cattle can serve as an example for efficient selection, but the Wildgehege Neandertal, a German zoo, did a very good job in creating and spreading very large-horned Heck cattle without maintaining any of the undesired Watussi traits. They did this by using one Heck x Watussi cow in the 1950s, and using her quarter Watussi son as a breeding bull. While the other Watussi traits got reduced to almost nil after decades, they always kept those individuals with large horns. Nowadays there are a lot of Heck cattle that look totally taurine but have impressively large horns like aurochs. Only in a few you can see the Watussi descent (like this Bavarian Heck bull), but as I said, I regard an undesired domestic zebuine trait not anymore worse than undesired domestic taurine traits. The Neandertal lineage left a big mark on the German Heck cattle population and it did not have any negative effects on the cold tolerance of the cattle at all.

So I see no problem with using a breed that is either zebuine or zebuine influenced if it contributes precious traits. One just has to know how to use it wisely and breed out the negative traits, just with any other breed.

Literature

1 Hiendleder, Lewalski, Janke: Complete mitochondrial genomes of Bos taurus and Bos indicus provide new insights into intraspecies variation, taxonomy and domestication. 2008.
2 Martinez-Navarro et al.: The Early Middle Pleistocene archaeopaleontological site of Wadi Sarrat (Tunisia) and the earliest record of Bos primigenius. 2014
3 Ryder et al.: A massively parallel sequencing approach uncovers ancient origins and high genetic variability of endangered Przewalski’s horses. 2011.
4 Soubrier et al.: Early cave art and ancient DNA record the origin of the European bison. 2016.
5 McDowell, McDaniel, Hooven: Relation of the rhomboideus (hump) muscle in zebu and European type cattle. 1958. 
6 Decker et al.: Worldwide patterns of ancestry, divergence and admixture in domesticated cattle. 2014.

Cis van Vuure: Retracing the Aurochs - History, Morphology and Ecology of an extinct wild Ox. 2005.


Saturday, 19 August 2017

Setting milestones for "breeding-back"

Now, in 2017, there are many different aurochs projects (Taurus cattle, Tauros Project, Uruz Project, Auerrind Project) and Heck cattle is still a very heterogeneous pool but slowly increasing in quality. More and more nature areas become free for natural grazing by large herbivores and the numbers of aurochs-like cattle is rising with each year. So it is maybe time to speak about the milestones of "breeding-back". What is the goal, and when can we consider it achieved?
In my previous post I explained why I think selective breeding with domestic cattle cannot deliver something that is a true aurochs in the strict sense of the word, but at least something that comes morphologically, ecologically and behaviourally very close. The ideal state is having these cattle living independently in the wild as wild animals, and successively having their genome shaped by nature. This is the final goal and it will take its time until it is reached. But I think there are several milestones for “breeding-back” that I want to outline here.

1. Creating a population that contains all achievable aurochs-like traits

Prior to “breeding-back”, there was no population of modern cattle in which all achievable aurochs-like traits were found. That is why “breeding-back”, no matter which project, has to rely on crossbreeding a set of breeds in which each breed contributes one or more desired traits (be it morphologic, ecologic et cetera). By doing so, you create a heterogeneous cross population that also contains a lot of undesired traits. It is the goal of selective breeding to get rid of those undesired traits, but before you can do that, all aurochs-like traits have to be present in the population in order to achieve a result that is as authentic as possible. We probably cannot achieve 100% perfect copy of the aurochs working with modern domestic cattle (for details, see here), but something that is very close in many aspects. That is why I speak of all achievable aurochs-like traits instead of all aurochs-like traits.
Taurus cattle, both the population at the Lippeaue and Hortobagy, have achieved this milestone. You can find all the desired achievable traits (accurate colour, body size, horn size, horn curvature, sufficient body shape, sufficient snout length, sufficient sexual dimorphism [more on that in a future post]) in both populations respectively. To give an example, forwards-facing horns are prevalent in the Lippeaue herd. Inwards-facing horn tips are present, but only a few individuals. Selective breeding has to fixate this trait in the population, and therefore get rid of the individuals with insufficient horn curvature. The same with snout length: some cows and bulls show an aurochs-like long snout, the challenge is to fixate it in the population.
As for the Tauros Project and the Auerrind Project, it might be too early to judge yet. For the Tauros Project, I fear that they will need some boost in horn volume and body size (for the latter, there is no data, however). The breed choice of the Auerrind Project should contain most of the achievable aurochs-like traits, the crossbreeds that will be born in the future will show how well traits such as sexual dichromatism and inwards-curving will work out horns work out. For the Uruz Project, there are no publicly known cross herds for now, so that I cannot say much yet.

2. Uniting all achievable traits in one individual

The next milestone would be to unite all the aurochs-like traits that are present in the population in one animal at least. This is a milestone that has not been reached yet. Of course the judgement is also a bit open to one’s preferences, as we cannot directly compare the individuals to living aurochs. For example, I think that the Taurus bull Lamarck and the Taurus cow Lisette are rather close to the goal already. But Lamarck’s horns could be more curved, the snout longer, the body still more athletic and probably also the legs slightly longer. And maybe I am picky, but I think Lamarck would also need more frizzy and curled forelocks in order to achieve "perfection" regarding aurochs-likeness. Lisette looked great overall, but her horns could have been larger and more curved, she was small overall and had white spots on the belly (how much does that matter? More on that in a future post). My choice of those two individuals as examples for very aurochs-like cattle is more or less subjective; there are many good individuals, also of pure breeds. Many Corriente and Lidia are rather close to what I consider the achievable maximum, but with noticable deficiencies (in those two breeds it is primarily the lack of body size, for example).
So we still need a bit patience and luck until the first individual that really displays a maximum of aurochs-resemblance that is possible. Furthermore, there will probably be no universal agreement on what actually is a perfect maximum of achievable aurochs-likeness. Different people also have different priorities.   

3. Getting rid of the undesired traits and create a stable population

When the first universally satisfying animals are born, the next challenge of selective breeding is to fixate this genetic make-up in the whole population. That means to finally exterminate the last undesired traits and create a truly homogeneous, aurochs-like population.
Cattle are a slowly reproducing species, and therefore it will take its time, probably several decades, until number 3 is achieved – especially since some projects, such as the Auerrind Project, have just started yet, and the Tauros Project is in the beginning phase as well. Some methods have been discussed on the web to speed up the process, including breeding schemes based on “true Filial crosses”, but it is important to maintain a certain amount of genetic diversity at the same time, as this is crucial for the populations health and adaptability.  

4. Releasing the animals and letting them evolve into a wild animal

Cattle that live and reproduce independently under natural circumstances without the need of veterinary care and supplementary feeding are the goal of all of the projects anyway, as they mostly serve a conservational purpose with the cattle as grazing tools. And for “breeding-back”, the goal of maximum authenticity has to be a truly wild animal at some point, as the aurochs itself was a wild animal per definition. That’s why I wrote

If ‘breeding back’ aims to approach the aurochs as closely as possible, the result has, ultimately, to be a wild animal.”

in 2015. Phenotypical plasticity and natural selection will alter the anatomy, physiology, behaviour, genetics and ecology of the aurochs-like cattle, and chances are good that this will make them even more aurochs-like (see the Dedomestication Series), and after a sufficient amount of time the population can be considered feral, and after that, truly wild. But it will take a very long time, probably centuries, until the selective pressure has altered the genetics of the population enough to speak of a truly wild animal. Nevertheless, we will probably live long enough to see those cattle looking and behaving like wild animals, and they will be suited to their environment.
Especially because the process of dedomestication can run parallel to “breeding-back”. Actually, the cattle of all those projects live in a more or less semi-feral state already in the grazing projects they are used. However, the breeding is still (and has to be) strongly regulated by choosing one breeding bull per herd plus selection. The next step would to let them breed naturally when they reached a satisfying level of aurochs-resemblance (with the competition of several bulls for breeding rights), and influence the population only by the removal of individuals that display too many undesired traits (however, I think this could be a mistake at too early phase, I can explain why). And in the long run, the population can reproduce freely and develop into a wild animal and artificial selection is done only on traits that would otherwise remain in the population for a very long time, such as recessive traits or domestic colour variants.
This is basically the plan that the Tauros Project has presented:

Although I do not think it is realistic that natural selection has enough time to turn the population into truly wild animals by 2025 or any point of this century, most of us will probably live long enough to populations of very aurochs-like cattle living freely and independently and behaving and looking like wild animals.

5. Numerous populations of aurochs-like cattle living in nature areas on the complete Holocene range of the European aurochs

Of course it is one of the goals to reintroduce cattle not only in one or two single reserves, but restore the ecological niche of the aurochs in as many reserves as possible on its former range. Actually, this milestone can be considered reached or almost reached already, just not with the desired very aurochs-like, stable and more or less dedomesticated cattle that are the goal, but the current “breeding-back” cattle that we have. There are “breeding-back” herds in nature reserves in virtually all regions of the European continent, from the Iberian peninsular to the Balkans, from the Netherlands to Latvia.

And once all those herds have reached the four previous milestones, we can confidently say that the niche of the aurochs has been filled as best as possible with domestic cattle until a true revival of the aurochs via genetic methods is feasible and executed (cloning or CRISPR-Cas9).
This is at least the way I would draw a scheme for the stepwise progress of "breeding-back", but I think that many people might see it in a similar way.  


Tuesday, 15 August 2017

New photos from the Watussi x Maremmana crosses

Today, a couple of new photos of the two Watussi x Maremmana crosses have been published on Facebook: 
Cross bull "Apollo" © Claus Kropp
© Claus Kropp
It is clearly visible that the young cow is of a lighter colour than his half-brother. I am very much looking forward to see what they are going to look like fully grown. Watussi obviously contributes alleles enabling the production of red pigment, so breeding out the Agouti dilutions in the second generation might already result in a very aurochs-like colour scheme.