Yes, most definitely. Cows are not like mares, does or ewes where they will only show signs of estrus in the presence of an intact male of their own species, a cow or heifer will come into heat regardless if there's a bull present or not.
It's possible, but if you catch that milk-thieving cow right away and separate her from the herd to wean her from doing that (or just outright cull her) the open cow shouldn't produce, or rather continue producing milk.
When she goes into heat or estrus. Check out the related question below.
Oestrous is when the cow shows "heat" meaning she is ready to be bred.
Yes, but for best milk production yearly breeding is advised.
Yes, if she is continuously milked everyday without any breaks in between.
Bred cow.
A bred cow or a pregnant cow, or, in the dairy industry, just a cow. In sale barns, if she has a calf at side, she is also referred to as a 3-in-1 or a three-fer or suckling bred cow. If she's lactating, like in a beef or dairy herd, then she's called a nursing bred cow, lactating bred cow or bred lactating/milking dairy cow. If she's not nursing or lactating, she's called a dry bred cow non-lactating pregnant cow if you really want to get technical. In the dairy industry, a lactating heifer that has already had her first calf is referred to as a first-calf heifer; once she has a second calf she is generally referred to as a cow. In the beef industry, a heifer that is pregnant with her first calf is called a bred heifer.
It's just like knowing when to put the bull out with the cows: When they're not pregnant and are ready to be bred. Most often it will be the cow herself that will tell you when she is ready to be bred, but you have to judge when the right time would be to AI her. Ideally 45 to 60 days after calving is when you should consider getting her bred. AI needs to be performed 12 hours after her first signs of heat.
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.
No, the cow will not go into estrus after she becomes pregnant.
Only once is necessary to get her settled. However, during a heat period, one cow can be bred to multiple bulls (if there are that many) more than once during her heat period.
She will, yes.