This question doesnt have one answer, because there are too many variables like size of cow, whether it was breed for beef or dairy i.e. type and conditions. Also the size of portion of meat per meal.
But here are some figures to go on with!
Excluding offal (ie heart,lights, liver etc),mechanicaly recovered meat and blood products:
Cows yield between approximatly 38kg (84lbs) meat and 56kg (123lbs)
A small portion of meat is about 100g (4oz) and a large portion 200 g (8oz)
So from a small cow you would get anything between 190 to 380 meals
From a large cow 280 to 560 meals.
But this is a Sunday and I am very bad at maths (and spelling) so this may be inaccurate!
Also before you go out on your hoss with your lasso remember rustleing is illeagal