In England and Wales it is called Year 6 and the pupils are usually 10 to 11 years old. Often it is the seventh year of school; the years being called Reception, Year 1, Year 2, Year 3, Year 4, Year 5 and Year 6.
Quick Answer. According to Animals Australia, the natural lifespan of a dairy cow is approximately 20 years. The average lifespan of a beef cow is 15 to 20 months.
Cows will produce milk for as long as a producer (dairy or beef) needs to have them produce milk, whether it's a time frame of around 6 to 10 months or longer, depending on their type and class of the cows and the producer's management criteria. The time frame, on average, is between or either 6 to 10 months. Dairy cows tend to be milked longer than beef cows due to the fact that they're selected to produce milk, not raise a calf. Beef cows will produce milk as long as they have a calf on them.