WESLACO – A local rancher says he lost cattle because of the way the insecticide is used.  

The parasite carried by the fever tick is deadly to cattle but farmers claim the way the disease has been treated could also be deadly.  

KRGV’s Christian von Preysing spoke with a Bayview rancher who says he’s worried about the use of the insecticide.  

"We've lost animals along with other ranchers. We've got affidavits where there are probably 200 animals that have died that we know of,” says rancher Danny Davis. 

The U.S. Department of Agriculture and the Texas Animal Health Commission manage the treatment of cattle that leave the quarantine zone with that insecticide.

USDA Commissioner Sid Miller explains the treatment system, called the spray box, mists a chemical called Co-Ral, which can get into the lungs of young or weak calves and kill them because it is done in an enclosed box that is completely sealed.

Miller further explains a less invasive, open-air spray method will become an option. 

Watch the video above for the full story.