Anthelmintic resistance in dairy calves

摘要

Anthelmintic resistance (AR) is said to exist within a population of animals 'when there is a greater frequency of individuals within a population able to tolerate doses of compound than in a normal population and is heritable' (Prichard et a1,1980).As the worm genes coding for resistance appears to exist in all worm populations, cases of AR begin to appear shortly after the introduction of a new anthelmintic onto the market.As the number of reports on the occurrence of anthelmintic-resistant cattle nematodes continues to grow worldwide (Gasbarre, 2014; Rose et a I, 2015), it is now becoming increasingly important for producers to re-evaluate their approach to nematode control so that the effective lifespan of some of the currently used anthelmintics is not significantly reduced.