Resistance to modern anthelmintics by ruminant nematode parasites is an increasing problem throughout the world. To date the problem has largely been reported in parasites of small ruminants, but there are increasing reports of such resistance in nematodes recovered from cattle. Until now there have been no published reports of drug resistant parasites from cattle in North America. In 2002 a pr...

It was recently shown that naturally occurring Mdr1a mutant fetuses of the CF-1 outbred mouse stock have no placental Mdr1a P-glycoprotein (P-gp) and that this absence is associated with increased sensitivity to avermectin, a teratogenic pesticide. To further define the role of placental drug-transporting P-gp in toxicological protection of the fetus, we used mice with a targeted disruption of ...

Emamectin benzoate, an insecticide derived from the avermectin family of natural products, has a unique translocation behavior in trees when applied by tree micro injection (TMI), which can result in protection from insect pests (foliar and borers) for several years. Active ingredient imported into leaves was measured at the end of season in the fallen leaves of treated horse chestnut (Aesculus...

During long time pest control was associated only to insecticides. The formulations were produced as an attempt of improving the insect control. However, some undesirable effects emerged in this time, mainly the toxin action and resistance. Insecticides are substances produced from chemical or biological products to control insect pests. The most common mode of action for insecticides is to kil...

Introduction Gastrointestinal nematodes, external parasites, and Fasciola hepatica (liver fluke) can all adversely affect productivity of cattle.(1-5) Previously, little to no work has been done to quantify the effect of treating yearling replacement beef heifers for both gastrointestinal nematodes and bovine liver fluke on weight gain, body condition scores, pregnancy rates, and subsequent wea...