Start Date: Jul 17, 2010
End Date: Oct 17, 2012
Ten horses will be placed in an approximate 20-acre pasture and allowed to freely range the entire area. A single tub containing an ivermectin-medicated protein block will be placed inside a central penning area supplied with water. The protein block will be weighed prior to allowing equine access. Once the horses are allowed access to the treatment block, the block will be weighed twice per week to determine (by weight) the quantity of material consumed by the horses. Once per week the horses will be haltered and a blood sample obtained from the jugular vein of each animal in separate vacuum tubes. Blood samples will be processed to obtain the serum from the whole-blood, and the serum will be frozen for later analysis. Serum samples will be analyzed by HPLC to determine the concentration of ivermectin in each serum sample. All data collected from the study will be tabulated to establish the amount of medicated material consumed and correlated to the concentration of ivermectin in the blood system.