Some cattle breeds have retained a lot of the original aurochs characteristics. This can be explained by two factors: either the breeds have remained rather unaltered throughout the ages, because of geographical isolation and therefore have a more direct line with the aurochs, or because of the wilder way they have been living, natural selection has bred them back to a more original state. Therefore, they have retained a lot of aurochs characteristics and they have reverted back to an animal that looks and behaves more like an aurochs.
Up to 2013, a number of breeds have been used that were considered suitable. However, the programme is flexible. If new studies would point out that other breeds would also prove useful, they will be incorporated. Especially if suitable breeds are locally available, they could be used as starting herds for crossings. Not only would this lead to higher numbers faster, but it would also be important for enhancing local support of the programme. The most important breeds being used consist out of the 'best breeds from two families of breeds: Podolian breeds and Iberian breeds:
Podolian breeds being used are:
A podolian breed we hope to incorporate in our programme is the Maltese oxen.
Iberian breeds being used are:
Furthermore we incidentally use some individuals of breeds with very good characteristics such as the Scottish highlander, especially from the perspective of future use in more nordic areas.
More important perhaps are breeds and families of breeds we don't use, because using them would imply that a lot of unwanted traits would get into the Tauros-population and it would take longer to get those traits out of the population. Obviously the modern breeds used for milk and beef production will not be used, but also breeds as Toro Bravo (Spanish fighting bull) - although the breed has quite some Aurochs traits - will not be used because the breed has been selected on on unnatural fighting behaviour for many centuries. But we also don't use breeds such as the Italian Chiannina, because there are better alternatives, such as in this case the Maremmana primitive. We also don't use Heck-cattle - apart from a very small group of animals for scientific evaluation only - that will be kept separated from the rest of the Tauros population - because the idea behind the Tauros Programme is that is better to start from scratch with the afore mentioned breeds. Using Heck cattle would imply that the negative traits would find there way in the Tauros population as well.