Agroterrorism - University of Georgia College of Veterinary Medicine

Cattle, sheep, and goats are three of Georgia’s important food-animal ruminants. They are consideredruminants because their four-chambered stomach enables them to digest copious roughage,which is inedible for direct human consumption. These three industries havegone through recent dynamic changes. Today’s cattle producers are workingwith narrow profit margins and must watch their expenses moreclosely than ever. Consequently, biomedical researchers are providingthese industries with ways to maintain healthy animals, which will helpreduce production costs. Mastitis, Johne’s disease, pasteurellosis, pneumonia,infectious bovine rhinotracheitis (IBR), bovine virus diarrhea (BVD), parainfluenza-3 (PI-3), and leptospirosis continue to challenge the immunesystems of Georgia’s cattle herds. Ruminant herd health as it pertains to foodsafety is also a major concern to consumers and producers. Scientists need to investigatepathogenic Escherichia coli, Salmonella, Campylobacter, and other food-borne organismsas to their origin, transmission, and prevalence.CattleCa 2+ entry mechanisms regulating the tone ofbovine small laminar arteriesLaminitis is a major disease in cattle. The availabletreatments are largely ineffective due toour lack of knowledge of the processes causing thedysfunction of small laminar arteries, which underliesthis condition. Elucidation of the processesthat cause laminitis has been hampered by a lackof techniques to study the functional aspects of thesmall laminar arteries that control local blood flow.We have directly addressed this issue by developingtechniques by which small laminar arteries can beroutinely isolated and their function examined invitro. Calcium plays a fundamental role in the regulationof vascular function. The hypothesis driving thisproject is that abnormal calcium influx plays a vitalrole in the expression of microvascular dysfunctionin laminitis. The main objective of this project is todetermine the importance of calcium entry mechanismsin normal laminar arteries with the view ofproviding key background information for futurestudies on small laminar arteries from laminiticcattle. The specific aim of the project is to determinethe relative role of voltage-gated, receptor-operatedand store-operated calcium entry in regulating theactive tone of bovine small laminar arteries. In thesestudies, small laminar arteries (100-300 µm internaldiameter, 1-2 mm in length) are being mounted onsmall vessel myographs and functional pharmacologicalstudies performed. These studies will define thecalcium-dependent mechanisms regulating the toneof vascular smooth muscle in bovine small laminararteries. The results of this project will provide thebasis for comparative studies on cattle with acutelaminitis and for the development of novel strategiesto treat laminitis.PI: Stephen J. Lewis (slewis@vet.uga.edu)14Veterinary Medical Experiment Station