Levamisole injectable is back?

[SBMF 2015]

https://www.zoetisus.com/products/cattle/valcor/

I always liked Levamisole injectable. It seemed like it worked on parasites the others didn't.
I was pretty disappointed when they quit making it.

 

[Lucky_P]

Widespread use and MISUSE of the macrocyclic lactones (MLs = ivermectin, doramectin, mocidectin, etc.) and benzimidazoles ('white' dewormers, like Panacur/Safeguard) has resulted in emerging resistance to these classes of anthelminthics in parasite populations all over the country. Once a population of worms has been selected for resistance to these two classes, that resistance appears to be 'forever'.
Levamisole is in another class, and as it fell out of favor &/or was unavailable for some years (i remember using it back in the 1970s/1980s - but you had to be careful with it on thin cows & Brahman- influenced cattle) it is still effective...for now. But...eventually resistance will emerge. But...evidence serms to suggest, that unlike the other two classes, it may wane over a 10-yr period, if withdrawn from use.
I've seen studies showing great results in stockers, growing heifers, etc., using a combination of a ML and a benzimidazole administered at the same time...but I'm unaware of recommendations for combo use in mature cows.
Properly timed and targeted anthelminthic use - deworming only those animals that 'need' to be dewormed- not every animal in the herd! - can go a long way toward protecting refugia ( the population of worms on pasture that have not yet been selected for resistance) and preserving effectiveness of the classes of dewormers.
This is the first I've seen of a combo ML+ levamisole; IDK if its a good idea or not. Time will tell, I suppose.