Sothere, have you actually had any problems with coyotes and calves?
Mainly sheep and goats the cow folks have called and it was a small pack of 5 juvenile males but they were in there.the worst is they will eat the umbil.cord right into the stomach while the calf is still alive.
Goat neighbor east of me 12 miles counted 26 +/- under the yard light last year while Kidding.sheep guy lost 15 lambs 2 years ago.Yeah they're a problem.
Heres our gopher,we call em "Road Boners"as they run out in the road and stand up,we shoot them with handguns and air pistols in a form of competition in the off season
http://www.foundalis.com/bio/zoo/sqr13lin.htm