All of the above, I guess. Depends on the season and the job.
Winter is insulated coveralls time (add the layers of toque, scarf, mitts and lined chore boots) over your jeans and shirt when you head out the door.
Spring in the pens means waterproof coveralls and slicker(muck hoses off easily), once again over the jeans and shirt. God bless those gumboots!
Summer and autumn loading or processing cattle in light coveralls or overalls (easier on the laundry than ruining a pair of jeans). And again on the gumboots (why ruin a good set of riding boots in urine and crap?).
Haying season means straw hat, long sleeved cotton shirts, and jeans. Getting skin cancer from sunburn is no joke.
Moving cattle out to pasture and to different sections of it in the summer you want to protect yourself from the branches and bush, so good felt hat (saves your face and ears when beating the brush), long sleeved shirt, oilskin coat (saves you from a soaking if it pours), jeans and chinks (to keep your knees from getting beaten up on the tree trunks and to keep pants from tearing on snags). After getting snagged in the throat last year by a broken branch, seriously thinking of adding a kerchief to the gear.
Gathering and driving the cattle in the fall means warmer gear. Usually pretty nippy here by the mid-October, so add more layers of clothes, warm gloves, and a wool scarf .
Not a glamorous wardrobe by any stretch of the imagination.
Take care.