This question has already been answered in a similar fashion. Please see that question below for your answer.
Breeding season for cows and heifers should be from 45 to 90 days long. Sixty days is considered optimum.
The anestrous period for a cow or heifer after calving is 45 to 60 days, but can range between 25 to 80+ days.
It's the end of the breeding season. Breeding seasons on any farm are normally 60 to 80 days long (the shorter the better since cows that do not get bred are deemed as cull cows because of their lower fertility rate), and in order to keep track and improve the fertility of the cow herd, the herd bull must be removed after a certain period of time.
The average should be around 45 to 60 days at the least.
Yak is a proper name
Breeding season for cows and heifers should be from 45 to 90 days long. Sixty days is considered optimum.
Heifers should be bred when they reach 15 months of age. Cows should be rebred 45 to 60 days after calving.
This all depends on your herd size, how long your calving season is, and the fertility of your cows and bulls. Some people will calve their cows 365 days a year, whereas others will have all of their cows calve within a time frame of 45 to 60 days, no matter if you have a herd of 50 cows or 1000. The better fertility you have in your cowherd, the shorter your calving season will be.
The anestrous period for a cow or heifer after calving is 45 to 60 days, but can range between 25 to 80+ days.
It's the end of the breeding season. Breeding seasons on any farm are normally 60 to 80 days long (the shorter the better since cows that do not get bred are deemed as cull cows because of their lower fertility rate), and in order to keep track and improve the fertility of the cow herd, the herd bull must be removed after a certain period of time.
As long as cows have been in existence, or the whole Bos primigenius species and subspecies have been in existence.
So long that it is impossible for a bull to "have babies." Bulls are responsible for breeding cows, not having calves themselves. It's just like asking if a man can have a baby.
Cows and bulls can both walk down stairs, as long as the stairs are wide and long enough. Some dairy sheds have stairs for the cows to walk down if the shed is on slanted ground.
Any age, really, as long as you make sure she maintains good condition, has her annual vaccinations, and can still suckle and wean a good calf. Some cows can still be mommas when they're past 20 years of age.
The average should be around 45 to 60 days at the least.
Yak is a proper name
The only way that were to happen is if they were not fed any feed for a long period of time, or are put on a poor-quality diet like straw hay for several months. Usually this is the best method when trying to get a number of fat cows in your herd to get their weight down before calving season.