The word must be out about these things...just ordered 50 to try from Valley Vet and they cost $2.15 each. Next price break was at 100 for $2.05 ea. I got the green ones with a wing nut. The orange ones were $1.69 each for 100.
I'm giving these things a try on a group of 40-some calves that are separate from the big herd. The old man isn't too optimistic about these things being worth the trouble, but I'm willing to try it. Worst case scenario, I'm out a hundred bucks and a couple hours of work. Doesn't seem like much of a risk.
We wean the first week of Oct. so I'll try to render my opinion shortly after. We'll have about 275 somewhat fenceline-weaned calves in addition to the 40+ two-step weaned calves.