Hmm.. I'm really trying, but I'm still not seeing it.. 
Think of it this way: She used Cydectin, but threw in some ivermectin too, just because. If there were worms in there which were susceptible to either ivermectin or Cydectin, *either one* will kill them.. If there are worms in there which are not susceptible to ivermectin, but are susceptible to Cydectin, the Cydectin will kill them.. So, in a sense, throwing ivermectin on top of Cydectin may be a bit like throwing matches on a fire..
Now, the only way I can see that she might build resistance by combining the two is if she were to have done a regular dose of ivermectin (and by regular, I mean goat regular...like, 1ml/20lbs by mouth, or whatever still kinda works on a given farm) and then added *just a dash* of cydectin at the end.. In that case, there may be ivermectin-resistant/moderately-Cydectin-susceptible/partially-Cydectin-resistant worms in there which survive the ivermectin, but also survive the *underdosing* of Cydectin and go on to make six hundred and fifty two million thousand bazillion little baby worms with the same characteristics.. Which is to say, all you really managed to do was kill what few ivermectin-susceptible worms there were, and all the *weakest* of the Cydectin-susceptible worms, and left the stronger of the Cydectin-resistant worms to repopulate.. Whereas, has the dose been adequate, it perhaps would have killed far more of the moderately-Cydectin-susceptible/partially-Cydectin-resistant worms and left only the very strongest -- but in far fewer numbers. Of course, leaving the strongest behind will always lead to resistance, and there's really nothing we can do about that except for leaving as few of them as possible..
In any case, though, I don't gather that a dash of Cydectin was the case here.. I gather the case was a double dose -- a full load of ivermectin, and a full load of Cydectin -- which is really no different at all from giving a full load of Cydectin alone, in terms of building resistance.
And hey, ya never know...maybe there was an oddball worm in there that was resistant to whatever it is that makes Cydectin work a little better, but was still susceptible to plain ol' ivermectin...and she killed it.
I kinda really seriously highly doubt it but ya never know..
Think of it this way: She used Cydectin, but threw in some ivermectin too, just because. If there were worms in there which were susceptible to either ivermectin or Cydectin, *either one* will kill them.. If there are worms in there which are not susceptible to ivermectin, but are susceptible to Cydectin, the Cydectin will kill them.. So, in a sense, throwing ivermectin on top of Cydectin may be a bit like throwing matches on a fire..
Now, the only way I can see that she might build resistance by combining the two is if she were to have done a regular dose of ivermectin (and by regular, I mean goat regular...like, 1ml/20lbs by mouth, or whatever still kinda works on a given farm) and then added *just a dash* of cydectin at the end.. In that case, there may be ivermectin-resistant/moderately-Cydectin-susceptible/partially-Cydectin-resistant worms in there which survive the ivermectin, but also survive the *underdosing* of Cydectin and go on to make six hundred and fifty two million thousand bazillion little baby worms with the same characteristics.. Which is to say, all you really managed to do was kill what few ivermectin-susceptible worms there were, and all the *weakest* of the Cydectin-susceptible worms, and left the stronger of the Cydectin-resistant worms to repopulate.. Whereas, has the dose been adequate, it perhaps would have killed far more of the moderately-Cydectin-susceptible/partially-Cydectin-resistant worms and left only the very strongest -- but in far fewer numbers. Of course, leaving the strongest behind will always lead to resistance, and there's really nothing we can do about that except for leaving as few of them as possible..
In any case, though, I don't gather that a dash of Cydectin was the case here.. I gather the case was a double dose -- a full load of ivermectin, and a full load of Cydectin -- which is really no different at all from giving a full load of Cydectin alone, in terms of building resistance.
And hey, ya never know...maybe there was an oddball worm in there that was resistant to whatever it is that makes Cydectin work a little better, but was still susceptible to plain ol' ivermectin...and she killed it.
I kinda really seriously highly doubt it
but ya never know..
