Me? I'm not into chemicals and don't have the equipment to spread it. Somehow, I'm thinking a little converted Windex sprayer just isn't going to "cut it" LOL!
The first thing I see is that this piece of land is on a shoreline. I'm wondering about exposing the cows to the elements once these bushes are gone, but then you have grass in Feb. which is wonderful! (I'm in Canada) So, just how bad are your elements at the worst time of year? What direction is the picture taken? I would consider fencing it and letting them in there anyway. Escape from bugs, shade etc, and if the bushes are non-toxic to them, they may just thin it out themselves and atleast make it more manageable for you. Cows are great for this, unlike horses. They're built low, have thick hides and wouldn't get all scratched up from being in there like horses would. I'd be considering giving the bushes some competition, Mother Nature's way. Takes time, but it works.