Video of a great Lidia bull

Repeatedly I wrote on my blog that I consider the Spanish fighting bull (Lidia) the most aurochs-like or least-derived taurine cattle breed that is left on this world. In the youtube video linked down below there is yet another example for a very aurochs-like Lidia bull. 

The bull appears at 0:22. Look at its horns, its morphology, its skull shape. Simply wonderful. All in all it is a very aurochs-like individual. The colour is not wildtype colour (which would be an E+//E+ genotype), but colour is an easy fix as it is controlled by only a few genes. The morphology, however, is controlled by most likely a very large number of genes and thus a bull that has the right morphology but not the right colour is much more useful for "breeding-back" than a bull with the right colour but not the right morphology. And considering that most "breeding-back" cattle so far have a morphology that is not quite there yet, this Lidia bull would help to boost their aurochs-likeness considerably.

However, this breed has to be used wisely due to its problematic behaviour. What I would do if I had the chance would be to create a herd of about 30 Chianina cows and let them be covered by this Lidia bull. The results will be F1 Lidia x Chianina that have both a full set of Lidia chromosomes and Chianina chromosomes. Then I would pick one of the F1 bulls (either the best-looking or least aggressive one), and let them cover all of the F1 cows. The resulting (roughly) 15 F2 will display a wide phenotypic variation spectrum. Some individuals might have the Lidia size and Chianina horns (not desired), or Chianina size and the horns of the Lidia P individual. It requires luck to get an individual with horns and morphology like the Lidia bull, Chianina size and Chianina leg length and an E+ phenotype without visible dilution factors et cetera. I would pick the best bull of the F2, also taking the behaviour into account for pragmatic reasons, and let him cover all of the F2 cows. Maybe the F3 individuals will be pretty good already and also more or less homozygous for the desired traits due to the consequent line breeding. If not, one could repeat the process endlessly (that way, highly inbreed and genetically homozygous laboratory mice lines have been produced that are used for genetic research. The so-called purging of deleterious alleles produces genetically homogeneous lines that do not suffer from an inbreeding depression), but I would expect that the F3 would be pretty good already. It would maybe lack horn volume for an average aurochs, but it would likely be within the variation of the European aurochs (compare with, for example, the Prejlerup bull). The genetic diversity would be narrow, but my goal would not be a large, genetically diverse population but rather a couple of high-quality, genetically comparably homogeneous individuals that are suitable for improving the aurochs-likeness of other herds. Bulls from such a line could be used as sires on other "breeding-back" herds. That way the potential of this Lidia bull would be used for the breeding of aurochs-like cattle. 

Unfortunately this is all a phantasy scenario of mine, but it is always great to see that there are such great Lidia bulls around. 

Bos primigenius or Bos taurus?

There is some confusion about which name is the proper scientific name for the aurochs, Bos primigenius or Bos taurus. In this post, I am going to investigate the question which of those names is the legitimate scientific name for the aurochs. 

If one considers domestic cattle and aurochs different species because the former has been domesticated, the case is clear which scientific names they should have: the aurochs would be Bos primigenius, described by Bojanus in 1827, and domestic taurine cattle would be Bos taurus, described by Linnaeus in 1758. But there is no scientific consensus on whether domestic animals and their wildtypes should be regarded as one species or separate species. I tend to not regard domestic animals as taxa that need a proper scientific name at all (go here for my post on that). 

So, if aurochs and domestic cattle would be one species, with the aurochs being the wildtype and domestic cattle man-made modified versions of the aurochs created by artificial selection, what is the proper scientific name for that species? This is now where it becomes tricky. 

Due to the rule of priority of the ICZN, the first name used to describe a species has priority. In this case, Bos taurus would be the proper scientific name of the species containing aurochs and domestic cattle because it is the earlier name. However, in 2003 the ICZN decided that 17 names of wildtypes that are pre-dated by names for domestic forms should be conserved, including Bos primigenius (opinion 2027). However, to complicate the issue, Linnaeus actually referred to the aurochs in his description of Bos taurus from 1758. He mentioned the aurochs as “ferus urus” (= “wild aurochs”) living in Poland. Apparently, he was not aware of the fact that the aurochs probably already had died out when he described the species (go here for the youngest aurochs remains currently known). This is taxonomically not relevant however, Linnaeus definitely described the aurochs and domestic cattle as one species in 1758. 

Referring to the aurochs as Bos taurus is therefore definitely legitimate. However, I prefer to follow opinion 2027, also because Bos primigenius at least has a holotype (the Haßleben specimen), while Bos taurus does not. Therefore, it is up to ones’ preference whether to use Bos primigenius or Bos taurus for the species that contains the aurochs, and also depending on your opinion on the taxonomic status of domestic animals in general.