In order for cattlemen to be successful, each of their cows need to raise one calf per year. Some ranchers use natural breeding for their herd (selecting bulls with the right genetics for their goals, and keeping their bulls with the cows during the breeding season each year). Others opt for using artificial insemination (A.I.). This method is more of the standard for dairy cattle, but when it comes to beef cattle, it just depends on whether or not it's practical for that operation.