Cattle and dairy cow have been one of the most experimented on gmos.
Livestock cattle have been experimented on since 1990, by Netherlands scientists who had been experimenting for years.
The first cow to be genetically engineered was in 1990, and his name was Herman the Bull. He was injected with human genes to make him produce lactoferrin, and when he was mated the genes were passed down to his calf.
Dairy cows have been genetically modified since 2010, they have been given genes to produce different types of milk such as breast milk from a human being, low fat milk, and even low-allergen milk.
Cows can be modified with genes to make their muscle grow rapidly to produce more meat for the world and increase the food supply.
As seen here, gmos can sometimes go horribly wrong. In cows, if the genes do not code correctly the animal can end up with up to 8 legs, many ears, and even 3 heads