Project Number: 6205-32000-034-21
Project Type: Nonfunded Cooperative Agreement

Start Date: Sep 01, 2009
End Date: Aug 31, 2013

Objective:
To determine the level of ivermectin in the blood serum of pastured cattle that are provided with free-access to a solid, cooked protein supplement that is medicated with ivermectin.

Approach:
Cattle will be placed in a 17-acre pasture and allowed to freely range the entire pasture. A single tub containing an ivermectin-medicated protein block and/or a single tub containing an ivermectin-medicated mineral block will be placed inside a central penning area supplied with water. The protein block and/or mineral block(s) will be weighed prior to allowing cattle access. Once the cattle are allowed access to the treatment block(s), the blocks will be weighed twice per week to determine (by weight) the quantity of material that is being taken in by the cattle. Once per week the cattle will be placed in a chute and a blood sample will be obtained from the jugular vein of each animal in separate vacuum tubes. Blood samples will then 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 then be tabulated to establish the amount of medicated material they are taking in and the subsequent concentration of ivermectin in the blood system.