Fly Management in Animal Agriculture Systems and Impacts on Animal Health and Food Safety

<p>NON-TECHNICAL SUMMARY: <br/>The faculty of the Rural Animal Health Management Section within the Veterinary Clinical Medicine Department has new faculty and house officers that are actively engaged in scientific discovery. We are in the midst of a survey on antibiotic usage in Illinois dairy herds and have active retrospective studies ongoing that will define and categorized the post-mortem findings from dairy cattle and whitetail deer over the past 10 years. These retrospective studies will help us begin to address what diseases have been most prevalent and allow us to correlate these finding with pertinent, ongoing clinical cases that are being treated by our section. We have a unique opportunity to further investigate these issues on a real time basis at the Veterinary Medical Research Farm (VMRF).The VMRFhas 35 acres of mixed grass and clover pastures that are divided
into 5 acre paddocks. Each of these paddocks has a shelter within the paddock and a water supply. Currently, we have a herd of Holstein heifers on the farm that we are rearing in conjunction with theCollege of ACES AnimalScience Department. Our goals are to grow these heifers to breeding age in a timely fashion and in order to do that we must maintain their health to the highest standards. During warm weather months these cattle are affected by several species of nuisance, biting and disease-transmitting cattle flies (Diptera) that settle or feed on grazing hosts and have been shown to lead to increased disease incidence, reproductive failure and reduced meat and milk yields, with significant economic losses arising as a consequence.

<p>APPROACH:<br/>Dairy heifers will be identified by unique ear tag numbers and the horn fly numbers that aggregate on them will be quantified each week. Horn fly populations will be monitored by counting the number of flies per side on heifers with the aid of binoculars before 0930 h. The number of flies will be recorded for each heifer as the fly season progresses. The number of flies on each heifer will be correlated with the pedigree of each heifer to determine if there are genetic differences in fly attractiveness. As these data are developed those heifers with high attractiveness will be identified and further investigation into the mechanism of how this attraction occurs will be made.Investigations into how flies are attracted to animals have found that semiochemicals (behavior and physiology modifying chemicals) are important in either attracting or repelling
insects. Our thoughts are that these compounds could be exploited as management tools for control of nuisance flies. These volatiles can be collected from individual cows by placing them in pre-washed stalls and collecting the air above the animal air entrainment. Air surrounding the animals can be drawn (1 L/min) through Pyrex glass tubes (3.9mm o.d., 2.4mm i.d.) containing Porapak Q (50 mg per tube, 50-80 mesh) over a period of several hours. The apparatus used to obtain the volatile collections were arranged such that relatively free movement within the stalls was allowed, thus obviating any stress in the animals. It is our intention to seek collaborators who will enhance our ability to address the roles and chemical nature of olfactory cues used in host location and selection by these flies.When flies reach an economic threshold control abatement procedures will be instituted. The
control measures will consist of ear tags impregnated with insecticides, pour-ons and premise insecticides. We will use the monitoring techniques described above to assess our control measures during year one.