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. 

Monday, 14 August 2017

The Murnau-Werdenfelser

One might wonder why this breed is particularly interesting so that it deserves an own post, except that its name sounds like a beer. Well, it is interesting mainly for two reasons. First, its colour scheme considering it is a rather derived Central European breed. Secondly, it was a more or less important founding breed of Heck cattle.

Murnau-Werdenfelser is of Bavarian-Austrian origin, descending from Gelbvieh, Braunvieh and other local breeds according to Wikipedia. Gelbvieh are, as their name suggests, rather light in colour – particularly, eumelanin is lacking. Braunvieh and other breeds might have contributed alleles producing more eumelanin. In any case, Murnau-Werdenfelser have the right colour scheme besides the Gelbvieh-like diluted ones. However, sexual dichromatism is reduced and variable. Some bulls are completely black in an aurochs-like manner, others show the colour of the cows. Most bulls seem to be somewhere in between. 

I do not know to which extent this breed was used in Heinz Heck's experiment as the literature is not precise. Cis van Vuure (2005) writes: "Heinz also used Werdenfelser cattle in his experiments, but Heinz himself makes no mention of this". He might have overlooked a remark from Heinz Hecks extensive article "Der neue Auerochse" ["The new aurochs"] published in 1980 in the international Heck cattle herd book stating: "For that I crossed Hungarian Steppe cattle, Scottish Highland cattle, Allgäuer, Werdenfelser, Angler, further also blackpied Lowland and Upland cattle, Podolian Steppe cattle and Corsican mountain cattle" (translated from German). However, he still gives no precise information to which extent the breed was used (in how many crossbred individuals, for example). 

Nevertheless many Heck cattle still bear a striking resemblance to individuals of this breed. I give some examples now that I found on google that could easily be mistaken for Heck cattle (in some cases especially if they had larger horns, but there are also many small-horned Heck cattle): 
All of these colour variants are still found among modern Heck cattle

Heck cattle is often regarded or claimed as a mix of "exotic" breeds such as the Spanish fighting bull (which is very likely not the case) and others. A closer look at Heck cattle's breeding history shows that actually Heck cattle also descends from a number of Central European breeds that left a clear mark in its phenotype, as the example with the Murnau-Werdenfelser shows. 

Saturday, 12 August 2017

The African aurochs

I finally get to making a post on the African subspecies of the aurochs, Bos primigenius africanus. I actually planned to do this post two years ago, but never found the time to do an appropriate artwork on its putative life appearance. This week I finally finished one, so I am going to sum up what is known about the life appearance, phylogeny and ecology of this subspecies.

Phylogeography: The aurochs probably originated in Africa

Previously, it was assumed in the literature that aurochs descended from the Asiatic species Bos acutifrons which lived in Asia 2 million years ago (van Vuure, 2005). However, the oldest remains of aurochs have not been found in Asia but in Africa. The remains include a huge-horned skull from Tunisia dated back to 700.000 years (Martinez-Navarro et al. 2014). Aurochs appeared in Spain shortly after this individual died, perhaps migrating directly from North Africa (my personal guess, but I do not know if they would have been able to cross the Gibraltar street via island hopping or something similar). This could mean that aurochs reached Europe twice from two different populations, and genetics indeed showed that Southern European and Northern European aurochs differed genetically (Mona et al. 2010). My suspicion is endorsed by the fact that the basalmost African aurochs skull also shows the largest horns known to date and that Pleistocen Italian aurochs have also been described having particularly large horns (Frisch, 2010). What is important to note is that there are no noteworthy osteologic differences between later B. p. africanus and B. p. primigenius, so that the differentiation of both subspecies might be based on solely geographic basis (van Vuure, 2005), especially if my suspicion is correct that European aurochs populations could be polyphyletic. What is interesting now is that the osteologically different B. p. namadicus seems to have diverged from the primigenius/africanus clade much earlier, somewhere 1,7-2.0 million years. Probably the progenitors of the namadicus clade migrated from Africa to India rather early. This supports the view that namadicus and therefore also zebuine cattle are a separate species, but that is only paperwork that does not alter the animals themselves therefore it does not really change my conceptions. More on the Indian aurochs in a separate post coming up. For previous posts and artworks on the Indian subspecies, see the 2015 post and the 2013 post (I consider the latter outdated). 

As a remark, I do not consider the 700.000 year old aurochs skull a member of Bos primigenius africanus, even though it is from Africa. I consider aurochs from that time the most basal members of the clade before any subspeciation took place. 

Paleoecology of B. primigenius africanus

The African aurochs was neither an animal of the savannah nor the Sahara. Rather, it was present along the northern rim of the African continent from Morocco to Egypt and along the Nile delta where it was abundant (van Vuure, 2005). These North African ecosystems where the overlap zone of both the African and European biome, where European megafaunal species such as wolves, brown bears, red deer and aurochs lived along African megafaunal species such as African elephants, rhinos or hartebeest. Certainly the African aurochs was adapted to the way more arid climate of this region than aurochs from Central or Northern Europe.

Life appearance of the African aurochs

As mentioned above, the literature says there were no noteworthy osteologic differences between later B. primigenius africanus and European aurochs. Genetics would further have to show whether there was a continuum to the Middle east or not.
However, there are at least three prehistoric stone carvings from Libya that suggest the African aurochs had a distinct trait that distinguished it from the European populations. While there are good reasons to believe that so-called colour saddles did not appear in wild European aurochs bulls, it was seemingly the case in at least some north African wild bulls.

The two pictures are scanned from Frisch 2010 and © by Rüdiger Lutz. For the third one, go here. They show two engravings that definitely show grown, male aurochs with a colour saddle that is clearly indicated and extends till the hips. It can be ruled out that they show domestic bulls as they date back to 12.000 years ago, and are probably fully grown as the huge size is implemented by the small hunters surrounding them. The uppermost carving is from Hadarin in Lybia, other one probably too. The uppermost not only shows the colour saddle but also nicely the white muzzle ring and the light colour of the horns. The third picture is less anatomically precise and is from the flickR stream of archeofan and from Lybia as well. The upper scan actually shows another individual with a colour saddle (right side down below in the picture) but the sex is not visible on the photo. They are all stylistically very similar so probably from the same culture. It is also possible that one artist copied from the other, which is why artworks are imperfect evidence, but in this case we would have evidence for at least one African aurochs bull with a saddle. 

So while there are many literature and art references that support black bulls for European aurochs and absolutely none that suggest bulls with a colour saddle for Europe, there are at least three artworks supportive of this trait in North African aurochs. It could be a coincidence and maybe both European and North African aurochs showed saddles on occasion, but I think the chances for that being a coincidence are way lower than for the conclusion that European bulls usually were of a black colour and North African bulls seemingly had a colour saddle.

This is actually not unlikely. The aurochs had a large distribution area, and we often find that subspecies of wild bovines may vary in colour. Actually, the fact that North African aurochs bulls might have had a colour saddle would simply imply that the sexual dichromatism was not as strongly expressed as in the European subspecies. Other wild bovine species show geographic variation in this respect as well. For example, the Java banteng (Bos javanicus javanicus) shows the same colour dimorphism as European aurochs: black bulls, reddish brown cows. The Burma banteng (B. j. birmanicus) has a very reduced sexual dichromatism, both sexes are of a light brown colour. The Borneo subspecies is intermediate. Also Gaurs vary in sexual dichromatism, some populations having virtually none while it is more or less visible in others. The African forest buffalo also differs in its colour from all the other African buffalo subspecies (which is one of the reasons why some regard it as a separate species).
So it is absolutely plausible that the African aurochs, as a result of genetic drift and living in a different habitat/climatic zone might have displayed a slightly different colour as the European subspecies. It would also be possible that the African aurochs had a longer dewlap, since bovids in tropical or subtropical climates tend to have longer dewlaps for display and thermoregulations, while those in more temperate climates have furry ornaments like beards or manes instead. 

I actually made a drawing of an African aurochs bull and cow, but that did not work out as well as I wished. So I took the photo manipulation of the Taurus bull Londo with the head of a Lidia bull (I was unable to find out the name of the copyright owner of the picture; if it is you and you want me to remove it from the manipulation, please leave a comment) and partly painted horns that shows what I imagine an aurochs bull to look like, and copied the saddle of this Pajuna bull on its back. I also gave it the light forelocks that often correlate with bulls having a saddle, probably as a result of reduced sexual dichromatism, although there is no direct evidence for it. Then I inserted it in a semi-desert landscape from the Mojave desert (I know, wrong continent; I had to remove a lot of Joshua trees. It is just a symbolic background) using a photo from Wikimedia Commons by Alen Istokovic. I am pretty happy with the result. Please do not use without permission, as I do not have the OK of the owner of the Lidia photo and the Pajuna photo.

“Breeding-back” the looks of the African aurochs?

A “breeding-back” project for the African subspecies is tempting. While it seems likely that many of the Iberian breeds are influenced from African domestic cattle, there is no solid proof yet that any cattle directly descend from wild African aurochs, which disappeared in antiquity. EDIT: Decker et al. 2014 (go here) find African taurine cattle to be the most divergent taurine cattle and therefore speculate that this was caused by introgression of B. p. africanus. The portion of African aurochs ancestry in African taurine cattle might be as high as 26%, although they do not have African aurochs aDNA to prove that directly (as far as I understand). However, I don’t consider it that dramatic, as the European and African subspecies probably were more or less closely related. A “breeding-back” project for the traits of the African subspecies would have to focus on the same objectives as those for B. p. primigenius, with the exception that colour saddles in bulls are appreciated and should be bred for. Lowering the mean degree of eumelanisation for bulls will probably result in some bulls displaying a reddish brown cow colour scheme (like this Pajuna, for example), just as bulls with a colour saddle are not uncommon in the projects focusing on the European traits.
A possible set of breeds to optically restore the North African subspecies could be:
- Maronesa (horn shape)
- Alistana-Sanabresa (similar to Sayaguesa but less eumelanised, bulls have a saddle)
- Pajuna (slender and many bulls have a saddle)
- Watussi (horn size, used only with caution)
- Maltese/Chianina (size, proportions, body shape)

All those breeds are from a more or less subtropical climate, so they should be suited to the North African ecosystems, especially Watussi. As for the use of Maltese vs. Chianina, it would depend on whether semen of Maltese bulls would be available (to avoid the annoying dilution genes of Chianina), if not, one would have to rely on Chianina. The African aurochs was probably not as large as Northern European aurochs, but one has to compensate the comparably small size of breeds like Pajuna or Maronesa. And you achieve good proportions and body shape with those large breeds.

Such a look-alike for the African aurochs that is suited to the local ecosystems could be reintroduced somewhere in North Africa along other megafauna. I suggest a “North African Kruger National park” just like I did it for Europe, inhabited by megafaunal species such as African elephants, rhinos, hartebeest, red deer, cattle, brown bears, wolves and others. However, the political situation in the North African states makes it unfortunately very unlikely that a megafaunal reserve of that kind will be realized in the near future.

Literature

- Cis van Vuure, 2005: Retracing the aurochs: history, morphology and ecology of an extinct wild ox.
- Walter Frisch, 2010: Der Auerochs: das Europäische Rind.
-  Martínez-Navarro, B., Karoui-Yaakoub., N., Oms, O. et al., "The early Middle Pleistocene archeopaleontological site of Wadi Sarrat (Tunisia) and the earliest record of Bos primigenius", Quaternary Science Reviews (2014).
- Mona et al. 2010: Population dynamic of the extinct European aurochs: genetic evidence of a north-south differentiation pattern and no evidence of post-glacial expansion.
- Hiendleder, Lewaski, Janke, 2008: Complete mitochondrial genomes of Bos taurus and Bos indicus provide new insights into intraspecies variation, taxonomy and domestication.



Wednesday, 9 August 2017

How good is the sexual dichromatism in the Lippeaue?

One of last week's posts was on sexual dichromatism in "breeding-back". Today's post will be on the same topic. I start with two pictures: 
The upper photo is from Hortobagy (© Istvan Sandor) and shows the breeding bull Rimu with a cow. The lower photo shows two Taurus individuals from the Lippeaue. Don't fall into the pitt concluding that these photos show good sexual dichromatism - it is not said that both individuals are closely related and inherit the sexual dichromatism that we want in these cattle. Their genotype is very heterogeneous and we cannot know for sure. That is why we should always look at the tendency in the total population, and I did this for the Lippeaue anno 2015. 

In my post on the genetic and developmental background of morphological traits, I outlined that it might be very difficult to impossible to achieve an authentic aurochs-like sexual dimorphism, in particular sexual dichromatism (the colour difference between the sexes), based on conventional phenotypic selection:

Always simply choosing red cows and dark bulls, or small cows and large bulls, or whatever sexually dimorphic trait, probably will work not here. You would actually have to choose individuals where the sexual dimorphism is laid down in the genome. A phenotypically red cow might either have a more or less strong sexual dichromatism (s. dimorphism in colour), or simply be red and have no sexual dichromatism at all, depending on the bulls that she would produce. The same is the case with dark bulls. How to know that? Well, at first the genetic background of the dimorphic trait has to be resolved, and then the individuals would have to be tested.

So not only would the auto- and gonosomal genes and alleles involved in sexual dichromatism have to be identified, each individual would have to be genetically tested. This would be very expensive and requires research. Therefore I concluded:

I think there are only two possibilities regarding breeding a good sexual dimorphism: either relying heavily on a breed where a well-marked sexual dimorphism is still retained […], or putting up with the fact that there will always be a certain number of cow-coloured bulls and bull-coloured cows

Nevertheless, this does not have to mean that the extent of sexual dichromatism cannot reach a satisfying level. I am going to have a brief look at some cases of breeding-back populations with a satisfying level of sexual dichromatism, and go deeper into my usual case-study herd of Taurus cattle at the Lippeaue in Germany.

As a brief reminder: standard “aurochs bull colour” is to be considered black with the exception of a dorsal stripe and a muzzle ring, the area on the back can also have a slight brownish tint but it is unlikely that European aurochs bulls possessed a so-called colour saddle. The full colour spectrum of the forelocks is unknown. “Cow colour” probably includes all shades of reddish brown to darker until black with a colour saddle or completely “bull coloured”. But those black cows were, according to written sources, very rare. For details, have a look at my previous post.

Sexual dichromatism in existing breeding-back populations

For the case of the Tauros and Auerrind Project, the time is surely to early now to judge sexual dichromatism yet – the gene pool is not mixed enough yet in the case of the Tauros Project, and the Auerrind Project is just getting started. For Taurus cattle, I pick the Lippeaue as an example but serve that for later. So what is left is Heck cattle for now.
Heck cattle are very heterogeneous in regards to sexual dichromatism, as they are in regards to all traits. In some herds, one has to conclude that there is little to no dichromatism at all (many bull-coloured cows, many bulls with a colour saddle). In many herds, there is a tendency of the cows being coloured lighter than the bulls but still contain many variations. In some Heck herds and lineages, however, a quite satisfying level of sexual dichromatism has been achieved. One good example is the herd at Hellabrunn zoo, Munich, at least when I visited it in 2011.
The Hellabrunn Zoo Heck herd has a really good colour and dimorphism
The Neandertal lineage has a satisfying level of sexual dichromatism as well. Many cows show the reddish-brown colour I we see in cave paintings. There are black ones too, of course. Both the Hellabrunn herd and the Neandertal lineage have a very good colour, very intense and seemingly cleared of dilution alleles (there have been no diluted individuals from these lineages for quite some time). Another herd with a good amount of sexual dichromatism that I know of is the one at the Lainzer Tiergarten at Vienna. But in a different way: there are no cows that can be considered “of a reddish-brown colour”, but the type with the dark base colour and the light colour saddle/back is prevalent instead. There were almost no black cows in the herd and no bulls with saddles when I last had a look at the herd in 2014.  Another Heck herd that I visited that also had a quite good colour is the herd at Tierpark Haag, Lower Austria, but the number of the individuals was so small that the gene pool cannot really be judged properly with only a handful of individuals.
The dimorphism in the Lainzer Tiergarten herd is good as well
So where did those Heck herds get their good dichromatism from? Of the founding breeds of Heck cattle, Corsican cattle is best in regards to colour in general and sexual dichromatism. The breed left a strong mark in Heck cattle’s phenotype, which is also not surprising since Heinz Heck relied heavily on crossed individuals with a high portion of Corsican cattle. And the comparably careful selection in both the Munich zoo and the Wildgehege Neandertal probably kept the genes responsible for good dichromatism abundant in those lineages compared to other Heck herds (which often turned into a bit of a “phenotypical mess”).

The sexual dichromatism in the Lippeaue

Taurus cattle is, just like Heck cattle, a mosaic population that is heterogeneous in appearance and instable in inheritance yet. This is not surprising as there are still some first-generation crosses in the herd, the youngest individuals are of the 7th generation already. Taurus cattle is heterogeneous, but one could still determine whether there is a tendency to sexes having different colours or whether the inheritance of colours is independent from sex. In order to determine that tendency, I decided to count the individuals and note their colour, and distribution among the sexes. I made two categories for the sexes respectively: for bulls, “bull colour” as defined above and anything that is less eumelanisized than that (so either a prominent colour saddle or reddish brown colour overall) and for cows either “bull colour” (or black, if you will; except for the light markings of course) and anything lighter coloured than that (so either black with a saddle, or the various shades of reddish brown). Some individuals show diluted colours where the red pigment is reduced. However, the amount of sexual dichromatism is determined by black pigment, so I counted those diluted animals with reduced red pigment but not the half-Chianina individuals (neither bulls nor cows) which have a semi-dominant dilution that reduces black pigment, what makes them not comparable. I counted the individuals in their summer coat, as the winter coat is often darker than the summer coat and a saddle might disappear that is otherwise present.
I used a photo archive I was provided by Matthias Scharf that showed all individuals present in the herd in the year 2015 on several clear photos. I counted only individuals that already had their adult colour, so no calves. Usually it would be problematic that only the breeding bulls are kept till full age, but luckily they kept a lot of young bulls with their adult colour until fall 2015 when they were either sold or slaughtered.
These are the results:

Total number: 71

Bulls total : 25
Bulls black: 22 à 88%
Bulls with a saddle*: 3 à 0,12%

* There where no reddish-brown bulls, and from what I know usually such bulls do not appear in the Lippeaue, except for half-Chianina individuals.

Cows total: 46
Cows “cow coloured”: 39 à 85%
Cows black: 7 à 15%

We should expect those numbers to fluctuate slightly with each year, and are of course dependent on the "selection policy" in the Lippeaue. But this should be a number that can be worked with. In my opinion, this is a quite satisfying degree of sexual dichromatism. In the past, I have been wondering what would be the minimum point from which on the sexual dichromatism can be considered satisfying, and I concluded that no bulls with saddles and only 5-10% black cows would be satisfying to me. The amount of dichromatism in the Lippeaue comes comparably close. The question is if phenotypic selection could increase it any further in this case. I think it would be difficult. But to me, the level of dichromatism in the Lippeaue is satisfying. It would be interesting to do the same evaluation for other herds, such as Heck herds with good dimorphism (f.e. Neandertal or Hellabrunn) and such with very low dimorphism. Perhaps this level of sexual dichromatism would also be found in a lot of other herds of Taurus and Heck cattle. It will be very interesting to compare it with future herds of the Tauros Project and Auerrind project that work with different breeds.

Where did the Lippeaue population get its good dichromatism from? Sayaguesa has almost no sexual dichromatism, so probably not that breed. Most likely it is thanks to the Heck cattle from the Neandertal lineage that were the base of the herd in the 1990s. It is also plausible that Chianina inherits some degree of sexual dichromatism masked beneath their colour dilutions, as Sayaguesa x Chianina cows tend to be of a much lighter colour than bulls of the same combination.