We have one of those Agri-fab vacuum wagons that we use with our garden tractor. We don't use chemicals on the lawn....free range guineas to keep the bugs/ticks in check.
The cows are not dumb....both ours and the neighbor across the street's angus all know when that sound starts up of the lawn mower and the vacuum wagon. They all start bellering like they are starving or something....and they are all far from that!
I swear, its like it is cow candy (we nicknamed it snackies) when we feed them the clippings. With ours (highlands) you have to be careful because they all will try to get up in there and "help" you unload it, by the mouthful, but the highlands and their horns present an extra caution.

There is usually 3 or 4 loads at least, usually give ours a couple and the neighbor's a couple. It was funny, the other day it wasn't overly dried out yet from all the rain lately, but the grass was dry enough we had to try and mow it. So didnt use the catcher.
Talk about evil stink-eye looks from BOTH sides........

.....daring to cut that grass and not give it to them! Sometimes they will follow along the fence as you cut, giving you those looks like "is it ready yet? C'mon hustle up there pardner!"