I got it from a Professional. Generic had to only prove to be 80% as
effective as the origianal to get cleared for sale.
My opinion is to use Safeguard for worming. Gets many, many more worms. There is supported evidence that the avermectin products only
get 50-70% of the worms, because of immunity buildup. Now take
that times 80% and you can see you really aren't cleaning up worms.
Plus the avermectin products won't touch Nematadiris, a worm
that can kill young cattle. When we run fecals and Nematadiris shows
up, the folks running the fecal get real excited. We did not have this
worm in Montana for a long time, but now we do. We see it quite a
bit. One positive for Nematadiris is too much.
We have our fecals run at an independent lab, not at the vets, since
most of their machines are set up for dogs, not cattle, and they miss
a bunch. That is why we were under the misconception we didn't have
worms in these northern areas. Believe me, we do have them.
We ran a fecal for a fellow who had been complaining that his cows
weren't shedding and had a reddish tint. He had been using Generic
Ivomec. His cattle had 7 DIFFERENT KINDS OF WORMS. I've never
seen a fecal come back with that many different kinds of worms.
My recommendation, pour for lice and grubs and treat for worms with
Safeguard. Either in the mineral, the feed or orally. We just did our yearlings and two-year olds and calves the
early part of July, doing it orally. The applicator works good. You can do
it at preg check time or to the calves when you pre-condition. You will clean up the calves and they aren't going to get re-infected when it is this
dry. Now in Canada, or where it is wet, the cattle could get re-infected.
Strategic de-worming is recommended at 6 weeks after turn-out to clean up the pastures.
We don't de-worm at preg checking, because we do that in October. If
we should get a wet fall, then the cattle would get reinfected. We pour them for lice and grubs at that time and worm using the mineral with
Safe-Guard in December. It's been working real well.
Refer to BEEF Magazine, April 2005, for an article on Parasites. It will
support what I have to say.
Hope this helps!