I agree with cheap hair dye. We like to use Clairol green box from Dollar General. I think $1.99 per box.
What we do for a full size calf is...
3 boxes of Hair Dye mixed as instructions say, then pour into Sullivans spray bottle, fill up with Kleen Sheen, spray on clean & dry calf, work in with massage brush, let sit for correct time as said on box, then rinse with cool water until it runs clear. Very important to get ALL of the excess hair dye out!
A few pointers.......
1) have a tail clamp, or always keep a hand on the tail - heifers especially like to swing their tail and swat you in the face when the tail is full of hair dye, and that stuff does NOT come off your face well (don't ask how I know)
2) We use AI (arm length) gloves - when you are working the hair with the brush, you will almost always get some above the wrist of the short gloves
3) When you are a middle age, balding man, and go to Dollar General and buy 10-12 boxes of Jet Black Hair Dye be sure to take a mental note of the look the cashier gives you when checking out! It is Priceless!
CyFarmer