The USDA says that an animal should yield 62% of live weight. I say that is high in most cases. My butcher at our slaughter house says to count on 25% of the live weight to be useable meat; and you will get in the neighborhood of 30% or so. It depends on the amount of finish the animal has, the amount of fat, and the size and density of the bones. If you get alot of cuts with bone in then the weight you get back; and are paying for, will be higher due to bone weight.
So being a dairy breed, realistically figure you will get 250 lbs useable meat back from a 1,000 lb animal. That's mostly all boneless cuts, and not alot of fat. Often it will be around 300 lbs avg.
And realize that about 1/4 of that will be ground beef, at least. I figure on at least 50 lbs ground beef on an animal.
I meant to say that an animal should HANG at 62% of live weight. And you should get 60% of HANGING weight in meat. So that still figures out to less than 40% of total live weight in meat So round figures still comes in at 350 +/- of live weight. You won't get that on a dairy breed carcass but you will get some very nice LEAN meat if it has marbled some as there will not be alot of backfat. The down side to that is there won't be alot of fat to mix in to make the ground meat....I like very lean but alot of people like it with more fat = juicier when cooking.