#cattle genetics

The KIT gene has many mutations in cattle, it causes white patterns, and sometimes roaning, in the cows coat.

One of them is present in British White, White Galloway and Belgian Blue and is called Cs29. It is an incomplete dominant mutation that when heterozygous makes the cow a speckled/roany color sided. Homozygotes have a white body with colored nose, ears and hooves, they sometimes have speckles on the body.

First photo is of heterozygous animals and second is a homozygous British White and White Galloway has something in addition to this pattern that increases the amount of white. Heterozygotes in these breeds have the same amount of white that a homozygous Belgian Blue has while homozygotes are pretty much completely white. This is likely a recessive modifier since white galloway crosses are seemingly unaffected by the modifier and have the typical heterozygous pattern.

Again, heterozygous top and homozygous bottom photo, both are homozygous for the modifier.

The pattern in the hereford, simmental and more breeds is caused by different number of duplications, cattle with less white might only have a partial dulplication while cattle with a lot of white might have more than one duplication. The pattern of white that these have is white on the face, legs, stomach and a stripe on the top of the neck in some. It is also incomplete dominant, so heterozygotes will have less white.

This is the wide range of patterns these mutations can have, how much white depend on whether the animal is heterozygous or homozygous and also how many duplications they have

Another mutation (named KIT^pinz), this time in the Pinzgauer, Gloucester and more breeds, causes a more clean looking color sided pattern, as opposed to the more roany ones. It puts more white towards the back of the body and avoids the face. It's also incomplete dominant. In the Longhorn and Florida Cracker there are modifying genes that increase the amount of white. In the longhorn there also seem to be a modifier that turn the coloredd patches on the side into many small spots, similar to ticking.

This is the range of white the pinzgauer mutation can produce, the first bull is heterozygous and the last two cattle have white boosters

The Pustertaler Spinzen and the Vosgienne has another mutation, Cs6, that is similar to the Cs29 mutation. It may be incomplete dominant though scientist are currently unable to differentiate heterozygotes and homozygotes in tests. It is very similar to het Cs29 but it doesn't seem to get as light colored as hom Cs29.

There's a mutation discovered in a Brown Swiss cow and her calf, it has a lot of similarities with sabino in horses.

Combinations When pinzgauer and whitehead are combined, the resulting pattern can vary a bit but typically result in an animal that has the pinzgauer white on the back and belly often with a white head. The legs are sometimes white as well.

Whn pinzgauer is combined with cs29, the resulting offspring is mostly white, more white than homozygous cs29 cattle.

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Cattle don't really have many widespread common MITF mutations.

There is one dominant de novo mutation in an Angus calf that caused colored patches on the head. Though this one hasn't been bred.

There's another in Brown Swiss that is somewhat similar to the belted pattern, though the white doesn't seem to consistently cause a complete belted phenotype and tend to put white on the legs and head. This mutation is dominant with incomplete penetrance.

A dominant mutation in Fleckvieh cattle causes a completely white coat with blue eyes and pink skin.

Another dominant mutation in the Holstein causes a similar phenotype to the dominant white, this one is called glass eyed albino (but is a form of piebaldism) this one doesn't always cause a completely white phenotype, color is sometimes present on the ears and in the eyes.

From my understanding, the spotted pattern in the holstein is caused by at least three, but maybe more, mutations on three different genes, KIT, MITF and PAX3 and each mutation is incomplete dominant. Many sources treat piebald as recessive though so there's probably more to it. The more mutations a cow has the more white the cow will have, so, for example, a cow that is heterozygous MITF and has none of the others will have much less white than a cow that, for example, is homozygous MITF and heterozygous PAX3. And a cow that is homozygous for all of them is going to have a lot of white.

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Further reading