Friday, 28 August 2020

A Watussi steer with perfectly aurochs-like horns

Recently I found a video of a Watussi individual with very aurochs-like horns. Normally, Watussi bulls' horns look more like that. This individual however has horns that have a perfectly aurochs-like curvature (yes the horns are very large, though there were Pleistocene aurochs bulls with horns only a little smaller). I was not surprised that this individual is obviously a steer. Steers often tend to have more aurochs-like horns. Why is that? I explain this in this post. Horn length and consequently shape is determined by developmental factors. Development is deeply changed in domestic animals, usually there is a premature stop in development, causing the animals to display paedomorphic features. Thus it is not far-fetched to assume that horns tend to stop growing earlier in domestic animals, producing the horn shapes they have (usually less curved than in the aurochs). Steers, however, have an atypical development as their gonads are removed. The body does not know when to stop development and thus they grow larger, taller and also the horns grow longer (for another example, go here). Coincidentally, this developmental elongation compensates the developmental delay that results from domestication, resulting in a wildtype-like outcome. This is what we see in the Watussi steer. 

This has two implications for "breeding-back". For once, it means that bulls with banana-shaped forwards-facing horns (as we see it in many primitive breeds and "breeding-back" cattle) actually have the right genes for an aurochs-like horn curvature (the horns would also end up longer). It are developmental factors that result in the domestic condition. Furthermore, the big question is then: can "breeding-back", with the cattle that we have, produce perfectly aurochs-like horns at all? Selecting just on the phenotype that we want would not reverse the developmental changes from wildtype to domestic that we have in cattle. However, there are occasionally bulls with horns very close to the original aurochs horn shape, such as some Maronesa bulls (and also cows). And maybe it is not a coincidence that this breed has also retained a substantial degree of colour dimorphism. 

6 comments:

  1. Those are the horns we are looking for!!

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  2. Put those horns on an animal that is 6 ft high at the withers and it is a combination of sayaguesa/chianina/maronesa/watusi/pajuna and people will pay attention.

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  3. I did hear something interesting about plains bison from a video about a bison ranch. Being castrated doesn't change the bison's growth. Question would be if castration has more of an effect on growth on domestic animals.

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    1. As far as I know it does affect growth in domestic cattle, the biggest Chianina individuals are all steers.

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  4. Obviously castration has an effect on the size of domestic cattle, but does it have the same effect on wild bovinae. Would it have the same effect on aurochs. If it wouldn't have the same size effect on aurochs is there something that changed with being domesticated the reason why steer grow more aurochs like horns. Maybe it was slower maturity that caused the shape of the horn.

    Here's the video where it mentioned that castrating plains bison does not effect their size: https://youtu.be/wqj9T6wSFMc?t=1175

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  5. Look this cow. https://www.diariodeleon.es/articulo/provincia/mantequera-recupera-carne-conservacion-medio/201906230400001901137.html

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