So how many steaks can you get from a cow? Well it depends on what types of steaks and what other kinds of cuts you may want. When we have an animal processed a general rule of thumb is that 1/2 of it will be ground beef, 1/4 will be various roasts, and 1/4 of it will be different steaks (this includes sirloin but not all of the steaks will be sirloin). Below is picture of where cuts are found on a cow.
One thing this picture does not mention is Ground Beef. Ground Beef will general be trimming from around other cuts, pieces to small to be used. Or, it may be that a person does not care for a particular cut and so it is simply ground up. For example ground chuck is made from beef in the Chuck area as opposed to having a chuck roast.
Hopefully this will answers some questions. Then again maybe you have more questions now. If so please ask.