You can't "call a Cow", they way you would call a bull. Just doesn't work that way. Saying that, a cow that has lost here calf can usually be attracted by the sound of a calf in distress but only if she lost the calf within the last day, maybe two. She will stay in the general area, usually within a quarter mile.
If someone kills a calf moose and removes it from the area, Momma will come to "investigate" a distress call.
A little caution here too, Momma moose may not be in the best of mood either, she's comming to assist her young who is calling for help. She can get pretty bitchy and those hooves can be deadly.
Those calls are actual moose. Practice them. The better you get,the better the chance of success. Personaly, I prefer a birch bark horn, 18-22 inches long, it reverberates the sounds better.
One of the most important components of deciphering a new hunting area is distinguishing between the summer and winter ranges for the game that you plan to pursue. Without knowing this you cannot make reliable assumptions about where the game will be come opening day. Knowing these areas will allow you to take the current weather (as well as the past couple weeks) and apply that to the landscape and make an educated guess as to where you might find that big buck or bull.
There are a couple ways...