| cooperia punctata: effect on cattle productivity? | cooperia spp. have become the most prevalent parasites in united states cow/calf operations as observed in the usda nahms (national animal health monitoring system) beef cow/calf survey in 2008. this is at least in part due to the widespread use of macrocyclic lactones that have recently been shown to have a reduced activity against these parasites. the effects of cooperia spp. on cattle productivity are largely unknown. this study was conducted to assess their effect upon cattle housed under co ... | 2011 | 21821358 |