There is a backlog of the Sustain III calf boluses but I bought some of the cow size the other day. If you want, PM me and I will see if I can get more and the price and send you some. I haven't checked on the Ivomec. We do not routinely worm the cattle unless they look like they need it. We do feed DE in our feed that we get delivered from the mill by the ton. I say it has made a world of difference. Some people say I am crazy. I found that when they put it in the layer feed that I used to get by the ton when I had layers free ranging, that they did not have the worm problems and yes I did do a fecal on them twice. A neighbor used to raise reg Red Poll cattle and he put DE in his mineral and did fecals. I used the same vet at the time and asked him once and he said that the cattle had next to no signs in the fecals so he was convinced. The man who used it, did not use any chemical wormers.
We have used the Ivomec for some of the lice and stuff, there are a few cows that are looking a little "moth-eaten" right now. But we have also used sabre pour-on for that. A good dust powder with DE is our go to. A vet once told me not to get too panicky over the lice, they will fall off as the cattle shed and I have not ever noticed lice on a shed out cow.....