Sunday, 6 August 2017

Colour saddles in bulls: good, bad or neutral?

The life appearance of living European aurochs is pretty well resolved. We have numerous well-preserved bone material, related species and descendants to compare with, and contemporaneous references in art and literature that provide us a clue on what the European aurochs looked like. However, it is not as precise as if someone would have taken coloured photographs or made taxidermies of a sufficient number of individuals back the time when they were still around and well, and therefore not all aspects of its external appearance are known with certainty, or the degree of regional and individual variation of traits that are not indicated by the bones. I made a post about traits where we have no certain clues for, such as the colour of the forelocks in bulls and if there was variation, or which colour shade was prevalent in cows.

Two further questions rise up in “breeding-back” concerning the colour of the bulls. Where there European aurochs bulls that showed a so-called colour saddle? And if not, should we still permit it in “breeding-back” bulls, especially breeding bulls?
At first I want to explain what a colour saddle is. In wild-type coloured cattle (phenotypically E+), both sexes are born with a chestnut-brown colour and eumelanisation (eumelanin is the black pigment, pheomelanin the red pigment) with black pigment starts from the head, neck, feat, pelvis and tail tip. The degree of eumelanisation is dependent on testosterone level (and, I hypothesize, perhaps also other signal molecules). In wildtype coloured cattle displaying sexual dichromatism, the melanisation of cows stops earlier than in bulls, leaving them lighter coloured. The “standard” aurochs bull colour that is suggested by the evidence involves full eumelanisation of the coat of the bulls with the exception of the muzzle ring and dorsal stripe (of course in domestic cattle, where selective breeding greatly altered the phenotypic traits and sexual dimorphism, you find a lot of  “bull-coloured cows” and “cow-coloured bulls”). In cases where the melanisation does not run until this maximum point but stops earlier, a light area on the dorsal and – depending on degree – also pelvic area remains. This is called a colour saddle. You find that in many wildtype coloured cows and bulls. For cows, it is universally desired. For bulls, there are diverging opinions. The photos down below show a fully melanised wildtype coloured bull (Churro, a Sayaguesa bull, photo by Matthias Scharf) and a wildtype coloured bull with a saddle (its son Linnet, a Taurus bull, photo taken by myself).

Margret Bunzel-Drüke from the ABU also pointed me to the possibility that a saddle in bulls might just be a very broad dorsal stripe, but I have to say I am not convinced of that. Colour saddles are usually not that sharp-edged, and usually show some sort of colour gradient. Dorsal stripes, on the other hand, are always sharp-edged and the colour is more or less homogeneous. And more importantly, even in the colour saddle itself you can usually discern the dorsal stripe, unless the colour of the saddle is very light.
Now I am going to have a look at the questions above.

Where colour saddles present in wild European aurochs bulls? When we discussed about bulls with colour saddles this year, Margret Bunzel-Drüke told me that the colour variant we want in “breeding-back” is called “castania” by Spanish breeders (and considered wildtype by us), and therefore cattle displaying this variant should simply display the colour of the aurochs. This is also the same case in horses, dogs, cats and budgerigars – when the genes are the same, they display the colour of their wildtype. However, there is a difference in the case of cattle. Not only the colour genes themselves determine what the final colour will be, but as outlined above, it is also dependent on the level of at least one signal molecule – testosterone – and therefore linked to sexual dimorphism. As an example, I think it is pretty plausible that Sayaguesa and Cachena have the same colour alleles (wildtype+ on each loci as I see no divergent colours). In both breeds, the sexual dichromatism is very reduced, Cachena being on the less eumelanised end of the spectrum, and Sayaguesa obviously on the strongly eumelanized end of the spectrum.
As a consequence, the question is not just which colour alleles were present in the aurochs but also how strongly marked the sexual dichromatism was in the case of the aurochs. For that, we have to look at the historical evidence we have.

Cis van Vuure, who intensively studied tons of contemporaneous literature and artworks featuring aurochs, is convinced that European aurochs bulls at least did not have a colour saddle. The famous cave paintings (Lauscaux, Chauvet et cetera) give us a clue about the colour of living aurochs at that region and time (Pleistocene, Southern Europe). They show aurochs cows of really all colour shades we find in living wildtype coloured cows, also a “bull coloured” one, but the bulls are shown always black. There are also some line drawings of bulls, but a saddle is not indicated (yet there are some small spots on the head and neck area – I assume these are meant to indicate curly hair but there are also other possibilities). Anton Schneeberger, who delivered the most precise verbal description of living aurochs in Gesner 1602, described the bulls being completely black except for the light dorsal stripe, and cows being of a chestnut colour, and only very rarely turning black as well. In the Holy Roman Empire of the Middle Ages, hunters categorized the aurochs as part of the “Schwarzwild”. In German, hunters like to categorize game after their colours (roughly): “Schwarzwild” means “black game”, and nowadays only includes wild boar as the aurochs died out 400 years ago. “Rotwild”, meaning “red game”, is a hunter’s term for Red deer. So it seems that a black or very dark colour must have been prevalent in the perception of an aurochs for the contemporaneous people (this, of course, neglects lightly-coloured cows; bulls probably got more intention as they made way more impressive trophies). The Carta Marina by Olaus Magnus shows a rider being attacked by a dark brown aurochs, from the year 1539. However, the drawing is very stylized. Sigismund von Herberstein was in possession of a stuffed aurochs coat, and it showed a black colour with a faint dorsal stripe. Plinius quotes an earlier source that describes the aurochs as the “black forest ox”. Romanian folk tales also speak of the “black aurochs”. Russian and Polish stories and expressions, however, speak of red or reddish brown aurochs. But it is unclear in these cases which sex is to be meant. The social system of cattle includes cow herds with calves and young bulls, where the prevalent colour would be reddish-brown, and solitary bulls. If one witnesses a cow-calf herd, he would most likely describe “the aurochs” as reddish brown. If one witnesses a lone bull, it would depend on the colour of the individual bull. For the references of these historical accounts, see van Vuure 2005.
So what to make of this? It is not only that there is no evidence for colour saddles in bulls. It is interesting that Schneeberger notes the presence of such a minor detail as the narrow dorsal stripe, but not a colour saddle. If some of the bulls he witnessed had one he might have mentioned it as well, especially since he mentions the very rare black cows. One could criticize that he does not mention the muzzle ring as well yet it is considered a universal trait of the aurochs, but old bulls often have a very reduced muzzle ring (see Churro) and perhaps not all aurochs had this trait; Bantengs and Gaurs are variable in this respect as well.
Even more interesting is that at least two North African prehistoric stone carvings that I am aware of show aurochs bulls being hunted (I am not confusing them with the tomb paintings that show domestic cattle) that definitely have an extensive colour saddle (one of them also shows the muzzle ring). These are line drawings and the saddle is indicated. Is it a coincidence that for Europe, although there are many artistic and written references to the colour of aurochs bulls, there is no evidence for a colour saddle and in North Africa at least in two cases? Of course this is possible, and we have no direct way to prove that, but I think not. I consider it more likely to say that European aurochs bulls probably lacked a colour saddle while the African subspecies either showed it on occasion or universally. Would not a shiny red colour saddle extending on the whole back of the bull be a rather prominent trait that is worth mentioning? And if there were indeed European aurochs bulls with such a trait, why do all the sources always support black bulls only (in the cases where bulls are definitely referred to)? Apart from that, the contrast between the reddish-brown saddle and the black surrounding colour was that striking that eyewitnesses would have barely simply described such an individual as being of a “brown”, “black” or whatever colour but probably refer to the saddle in particular (would you when taking a look at a bull like Linnet on the photo above?).
So it seems more likely that European aurochs bulls never, or in very rare cases (twin births, after injuries of the gonads) ever had a saddle and that they were universally black, while there were black cows on occasion.

Should we permit bulls with a saddle for breeding then? Currently, all “breeding-back” projects permit a colour saddle in bulls more or less. I have always been against the use of bulls with a colour saddle as breeding bulls because of the risk of reducing the sexual dimorphism of the herd. In a previous post, I outlined that always picking black bulls and red cows for breeding probably will not result in the strongly marked sexual dimorphism of the European aurochs because one would have to consciously pick those individuals where sexual dimorphism is actually laid down in the genome. A black bull might just as well inherit black or very dark cows. Without knowing the exact genetic background of sexual dichromatism in cattle and without screening each individual for it, we can never know whether a black bull or a red cow inherit the sexual dichromatism we want. In the case of a bull with a saddle, however, we can be sure that the sexual dichromatism is reduced and since the sexual dichromatism is already less than in the aurochs, using such an individual for breeding might reduce it even further (the same goes for black cows of course, but black cows are confirmed to have existed in Europe while bulls with saddle probably did not). There is one possible example for that in the Lippeaue.
In the Hellinghauser Mersch herd, the Sayaguesa x (Heck x Chianina) bull 42 623 is currently used as a breeding bull. This bull has a colour saddle but does not display any colour dilutions. Some of its male offspring show a colour saddle as well, and I got the impression that they do that more often than the offspring of the black bull Lamarck. One of the young bulls I spotted in the field has a rather extensive saddle, or actually it is a brown back that gives it the colour of a cow. Using this individual for breeding might probably result in a number of wholly reddish-brown bulls appearing in the next generation. I would definitely not recommend using a bull with saddle or brown back for breeding if it itself descents from another bull that had a saddle as well. It might make this trait even more common in the population and lower the variation span towards more brownish bulls.

Nevertheless, the degree of sexual dichromatism is just one of many traits that “breeding-back” focuses on. Of the five breeding bulls at the Lippeaue, two have a colour saddle, but both of them are valuable for breeding. Linnet has a good horn curvature that shows the desired inwards-curve and 42 623 is a 170cm giant with a prominent shoulder hump. So the colour saddle can be permitted as both bulls contribute precious traits to the herds. It is like the fact that too small horns or such of insufficient curvature are not desired, but a bull might contribute other desired traits that are otherwise rare in a population, so that this deficit can be connived and corrected in later generations. There are also varying degrees of a colour saddle. For example, a saddle can either be very small or very faint (such as in the Taurus bull Luxus, which was used as a breeding bull for a short time about ten years ago). Also, subadult bulls might show a saddle but outgrow it as they age, such as Manolo Uno, the most famous Tauros bull to date. However, I would not use a saddled bull that itself descends from such a bull, as there is the danger of perpetuating this trait.

So a bull with a colour saddle does not always have to be selected out, but I recommend to avoid this trait for breeding bulls unless it has a number of otherwise valuable traits.


Cis van Vuure: Retracing the aurochs: history, morphology and ecology of an extinct wild ox. Pensoft, 2005. 


  1. Hallo Daniel
    Ich habe eine Frage: Sexualdimorphismus beschreibt ja den Unterschied zwischen männlichen und weiblichen Individuen einer Population. Das heisst, wenn ich nur ein Individuum sehe, kann ich nicht beurteilen, wie gross der Dimorphismus ist. Ich gebe dir recht, dass das Ziel ist, schwarze Bullen mit Aalstrich zu haben. Aber es ist auch ein Ziel einen ausgeprägten Dimorphismus zu erreichen. Heisst braune Kühe und nicht schwarze oder sehr dunkelbraune. Nur weil ein Bulle schwarz ist, heisst das nicht unbedingt, dass er Gene mit einem grossen Sexualdimorphismus aufweist, sondern einfach, dass der Grad an Eumelanisation sehr hoch ist. Als Beispiel würde ich sehr gerne die beiden Sayaguesbullen aus dem Auerrindprojekt nehmen.
    Die beiden sind Halbgeschwister und haben den selben Vater. Wenn man die beiden Mütter ansieht, hat der schwarze Bulle Takkie eine sehr dunkle Mutter und Leo (schwarz mit rotem Sattel) eine sehr helle Mutter. Jedoch bin ich der Meinung, dass Leo den grösseren Sexualdimorphismus zu seiner Mutter aufweist, wie Takkie und finde deshalb Leo einen sehr guten Zuchtbullen (nicht nur wegen des Sexualdimorphismus) trotz des Sattels. Das Ziel ist es beides zu erreichen. Einen hohen grad an Eumelanisation bei Bullen --> schwarze Bullen mit Aalstrich und einen ausgeprägten Sexualdimorphismus --> braune Kühe. Wenn man nur darauf achtet, dass die Bullen Schwarz sind, wird man das andere Ziel meiner Meinung nach nicht erreichen. Das Ergebnis wäre dann (etwas überspitzt) schwarze Bullen und schwarze Kühe. Was meinst du dazu?
    Liebe Grüsse

    1. Hallo Simon,
      ja, ich sehe das ähnlich. Selektion nur auf schwarze Bullen könnte langfristig zu einem drastischen Rückgang brauner Kühe führen, weswegen man ja üblicherweise ja auch aktiv braune Kühe mitbevorzugt, was wiederum dazu führt, dass Bullen mit Sattel immer wieder auftreten. Deshalb bin ich in meinem vorigen Post, wo ich mich der Problematik ebenfalls widme, zu dem Schluss gekommen, dass phänotypische Selektion wohl nicht zu einer Fixierung eines starken Farbdimorphismus wie beim Ur führen kann, sondern immer abgeschwächt bleiben wird. Man müsste wohl wirklich jene gono- und autosomalen Faktoren, die einen starken Farbdimorphismus verursachen, identifizieren und möglichst jedes Individuum (oder auch nur die Zuchtbullen) genetisch dafür screnen. Das wäre natürlich teuer und aufwendig, und man müsste vorher noch extra forschen. Außerdem kommt wie immer noch das Problem dazu, dass man es ja mit anderen Merkmalen balancieren muss: Wenn man nun einen tollen, großen, schwarzen Zuchtbullen mit toller Körper- und Hornform hat, aber es stellt sich heraus, dass er schwarze Kühe vererbt, soll man deswegen dann auf all die anderen Merkmale verzichten oder es in Kauf nehmen? Deshalb glaube ich, dass der Dimorphismus zwangsläufig immer etwas reduzierter als beim Vorbild bleiben wird. Aber vielleicht ist das nur halb so schlimm: es gibt manche Heck-Herden, die einen ziemlich guten Farbdimorphismus haben (Hellabrunn, Lainz, Neandertal), und ich habe neulich mit einem Photoarchiev den in der Lippeaue erhoben und das Resultat ist zufriedenstellend (darüber kommt demnächst ein Post ;-) )
      Die Frage ist nun, wie nun in der Natur der Farbdimorphismus überhaupt entstanden ist, denn da war die Selektion ja auch nur phänotypisch. Es wäre möglich, dass der ausgeprägte Farbdimorphismus mit anderen Merkmalen welche leichter durch phän. Selektion zu fixieren sind gekoppelt ist, und so entstand. Wir wissen aber nicht welche und es ist eine persönliche Vermutung von mir. Übrigens kommt mir vor dass dunkle Bullen in Oostvaardersplassen mittlerweile etwas häufiger sein könnten als früher, aber das ist mein subjektiver Eindruck der leider im Nachhinein nur schwer quantifizierbar ist.

    2. Sali Daniel.
      Herzlichen Dank für deine Antwort. Ich nehme an, dass die die wildfarbene Färbung bei Kühen und Kälber der Feindvermeidung dient und das Schwarz der Bullen sie als potenteren Geschlechtspartner identifiziert (wie z.B. bei den Kohlmeisen oder Haussperlingen. Umso schwärzer und grösser der schwarze Latz desto potenter) So macht es durch die natürliche Selektion Sinn, dass die Kühe wildfarben bleiben und die Bullen möglichst schwarz werden.
      Ich weiss, dass Geschlechtsdimorphismus nicht einfach ist zu fördern, da er an einem einzelnen Tier nicht beurteilt werden kann sondern nur an einer Population. Aber in so gut dokumentierten Zucht"populationen" wie gewisse Rückzüchtungsprojekte, sollte dies doch möglich sein, da ja die genauen Verwandtschaftsgrade bekannt sind. Man könnte z.B. die Farbe aller weiblichen Nachkommen mit der Farbe aller männlicher Nachkommen einer Linie miteinander vergleichen. Dies gibt dann eine Aussage über den Grad des Geschlechtsdimorphismus. Wichtig ist mir einfach, dass Geschlechtsdimorphismus nicht mit Grad an Eumelanisation verwechselt oder gleichgestellt wird. Z.B. sind praktisch alle Bullen bei der Rasse Eringer schwarz. Aber auch praktisch alle Kühe --> hoher grad an Eumelanisation, praktisch kein Geschlechtsdimorphismus. Im Vergleich zu z.B. Maremmana primitivo: Bullen Schwarz mit weissem Sattel, Kühe weiss. --> hoher Grad an Geschlechtsdimorphismus, mittlerer Grad an Eumelanisation.

      Liebe Grüsse

    3. Hallo Simon,
      ja, das ist auch mein Gedanke zur Evolution des Dichromatismus beim Auerochsen. Schwarze Bullen haben vermutlich einen Fitnessvorteil durch female choice.
      Man könnte natürlich anhand der Nachkommen versuchen abzuschätzen, wie gut der Dimorphismus genetisch ist. Dafür braucht man aber, aufgrund der hohen Heterozygosität der Kreuzungspopulationen, aber eine ausreichende Zahl an Nachkommen und mit verschiedenen Partnern - drei Tochterkühe werden da für eine Kuh nicht aussagekräftig genug sein. Das heißt das ein Tier dann auch bereits lange genug im Einsatz sein muss um beurteilt werden zu können, und dadurch bereits eine Spur im Genpool hinterlassen hat, egal ob der Dimorphismus gut ist oder weniger.
      Was Eumelanisierungsgrad vs. Dimorphismus angeht: Die beiden Begriffe sind natürlich nicht synonym; ein starker Dimorphismus ergibt sich aus starker Eumelanisierung bei Bullen und schwacher bei Kühen. Im Falle von ursprünglichen Maremmana würde ich ihn noch nicht als "hoch" ansprechen, weil die Bullen eben einen Sattel haben, deswegen ist er für meine Ansprüche "reduziert". Eine der wenigen Rassen die einen sehr zufriedenstellenden Dichromatismus hat ist meiner Einschätzung nach Maronesa. Den würde ich als hoch bezeichnen. Aber hier beginnt wieder die Subjektivität ;-).
      Ich schließe ja keineswegs aus, dass es möglich ist, einen guten Dichromatismus zu züchten - die richtigen Ausgangsrassen und etwas Glück gehören dazu. Es gibt ja Hecklinien, die einen guten haben, und ich habe neulich den in der Lippeaue Stand 2015 erhoben und er hat sich als gut herausgestellt. Der entsprechende Post kommt heute noch online ;-). Es wäre interessant, dass in der Zukunft auch mit den Tauros- und Auerrindpopulationen zu machen.

  2. "two North African prehistoric stone carvings that I am aware of show aurochs bulls being hunted (I am not confusing them with the tomb paintings that show domestic cattle) that definitely have an extensive colour saddle"

    Are there pictures of them online, could you give a link ?
    By the way, i googled for some stone-art and the proportions of this carved Wadi Aramas Aurochs :
    remind me the proportions of the Axarquía-bull you can see here at 5:10 :

    1. Well Chianina is used in breeding programms, maybe Maltese will be used...why doesn't anyone try to get some Axarquia in ? They are big, they have thick horns and look Auroch-like.
      Maybe they look this way because they aren't geneticlally far from them, at the video they wrote these are related to extinct Castillian. I think i've read somewhere that this breed also had an influence on Pajuna.
      They could get crossed to Sayaguesa, and then maybe some minor influences from Maremmana(too pale) and Pajuna(too small here), and that's it what one gets when trying to stay genetically close.
      Any opinion ?

    2. I take my hands off anything that alleges "genetically close".
      For Axarquia, I wish there was reliable data on the size of these animals. The bulls in the videos look large, no doubt, but I don't think they reach 170cm.
      I haven't found those two stone carvings on the web yet that show aurochs bulls with saddles, but one of them is very similar to the one you linked.

    3. Look at the cow at 1:35 and the bull at 3:30/3:45.
      In the discription they say "mil quinientos kilos de peso y casi dos metros"...
      I would wonder if they are more distant to auroch than Chianina, for example. I think that for animals from spain that look that way it's likely that they are genetically somewhat closer, with tha chance of beeing very close to an Auroch.
      These are from the area where Pajuna is also from.

      If one of your saddle stone-carvings was this one :
      ...then here i think it's erosion.

    4. Now I know of three stone carvings showing aurochs with a saddle. That's certainly not erosion as the edge of the "saddle" is clear and smooth, and the mealy mouth and light horns are indicated in the same way. One of the stone carvings I am talking about is from Hagarin in Libya.

    5. The saddle extends too high, up to a crack in the stone. So the lower part of the saddle could be part of the rock-art, but it's connected to the upper part...however with the big head and the small horns i think the figure could show a (male) calf.

    6. That's definitely a bull, and the artist was surely not interested in drawing each part anatomically precise. That's why nit-picking on rock art is doomed to fail, but still a lot of people have a tendency to do it.

    7. Well, compared to the other one this one looks less adult.
      Nitpicking on nitpicking is doomed twice, by the way.

    8. I really see nothing that points to this carving showing a calf. There are still two other carvings showing bulls with a colour saddle, stylistically similar but more refined and definitely grown bulls.

    9. A lazy artist got attracted by an erodet spot, that would just be perfect for a juvenile auroch at sunset.
      He put some attention to the head, but when it came to the legs he had to hurry up, because it was getting too dark.

      Has less hump&horns than the other one. I don't know these other 2 carvings.
      Do they also show this curvature ?

    10. I think that you see what you want to see. The area does not look eroded to me but artificial, and I see no reason to think it is a juvenile animal.
      I'm going to scan and upload the other two carvings for my upcoming post on the North african aurochs. They are stylistically very similar to the carving, but more precise.

    11. Well, it's just that the hump extents over the body, at least it looks like this on this one photo.
      And the other carving is much more stylish, think the curves are similar to assyrian artwork.
      So maybe these small odd-shaped horns correlate with domestication ?
      But i'm just speculating...

    12. Couldn't find another source for these supposed Auroch-carvings.
      However in Algeria there is rock-art that shows domestic cattle, done in a similar style as the refined bull. 4th row, left picture :
      This is definetly not a prehistoric work.

    13. I'm going to upload those aurochs carvings when I do my post on the African aurochs in a few days.

  3. "I take my hands off anything that alleges "genetically close"."
    Not sure if i understand what you are meaning. I just refer to this page 16 here :

    1. Genetic studies have to be published in peer-reviewed journals, otherwise "nothing happened" in the academical sense. What is given in the Rewilding Europe article is not precise enough for me to work with. Furthermore, "genetic proximity" in the sense of f.e. neutral variations on phylogenomic markers is nice but meaningless in practice. What really counts are the dramatic genetic differences between aurochs and domestic cattle that I outlined in other posts (f.e. the recent one on the genetic background of traits).

    2. Well, i should leave this to scientist. However, these breed has a very primitive expression to me. Maybe it makes good bulls, with thick horns and good humps. It's very rare. With the average size i think Sayaguesa-cows could be a match for crossing in.