I've used diesel for around 20 yrs. Re-dousing takes about a quart (1/4 gal) for a 10 ft rub. About 75 cents for diesel maybe a dollar for 4 oz of permectrin II. $1.75 or $2 per week through the fly season.

Well worth it to have the flies under control and cattle comfortable and grazing, not trying to constantly shoo flies.

No problems on my thick-hided Herefords.

P.H. White, a vet who came up with the rubs, used to recommend diesel on his website.