If you want to improve pasture, there is no better tool than using herbivores. Cows are best because of their weight and the shape of their hooves. Please check out "Mob Grazing". Also see
http://www.greenpasturesfarm.net . Home of Greg Judy who has done amazing things with cattle. Also google
Holistic Management International.
The bull will help with improving your pasture, but it would be great to get some more cows/heifers in there to increase animal impact and the amount of manure and
urine. Move the cows to a new spot at least every 3 days to prevent overgrazing, and don't allow them access to pasture they have already grazed until it is fully recovered. To see if a grass plant is fully recovered, see if you can find 4 leaves. If you do, the bottom leaf closest to the ground
should start to turn brown/yellow at the tip. If you see this, the grass is recovered and can be grazed again.
Best of luck with that bull running around!