4
Breed your cattle. Know when your cows go into estrus, when they're ready to breed, and go from there.
If you are using a herd bull, you will not need to worry about when your cows go into heat, only when they have been bred for record keeping.
Follow the steps outlined in the article "How to Artificially Inseminate Cows and Heifers" to know how and when to AI your bovine females.