The first question has already been answered in a separate question. As for the second, that is all up to the hormones surging through her body that keep her in heat.
Please see the related questions below.
A Jersey cow should be cycling, on average, once every 21 days.
If she's in heat, most definitely. Often a bull will go look for the cow that is in heat, no matter if he's the neighbor's bull or not.
No, the cow will not go into estrus after she becomes pregnant.
Since ovulation occurs a couple days after a cow or heifer has gone into heat or estrus, it occurs once every 17 to 24 days, which is the same time span a female would go into heat.
Normal female hamsters go into heat every 4 days. they stay in heat for 1 day only.
First of all, let's do the math here. One year has 365 days, and the average estrous period of a cow is 21 days. So to find how many times a cow will go into heat in one year is 365/21 = 17 days. Thus, a cow (if not bred during that year) will go into heat 17 times in one year.
A barren cow is another name for an open cow or heifer. Barren cows are cows that are not pregnant.
You stay still when you rope him then when he stays till you go
Calves don't grow into cows. They stay small and you brush them as opposed to milking them.
Every 6 months.
When the boxers are on heat, they usually mate just like the cats.
pigs stay in heat for about 21 days then for about 1 month your pig will be back in its heat