Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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A Multifactorial (Multiple Etiology) "Train Wreck" in a Flock of Meat Turkeys A.A. Bickford, F. Sommer, B. Charlton, and G. Cooper California Animal Health and Food Safety Laboratory System Turlock Branch Laboratory, P. O. Box 1522 Turlock, CA 95381 This presentation summarizes findings in a flock of 5000 hen turkeys started in early May 2004 in Central California. These birds did well through the first 10 weeks of growout with mortality losses at about 3%. During the 10th week a few undersized birds were noted and laboratory evaluation confirmed mild enteritis associated with mild coccidiosis and rotavirus (noted on direct electron microscopy of intestinal contents). In two additional submissions during the 11th and 12th week enteritis was also confirmed and evidence of additional enteric pathogens (hemorrhagic enteritis virus and cryptosporidia) was noted. At 11 weeks one bird was noted to have squamous metaplasia of the trachea. Morbidity and mortality increased remarkably during the 12th and 13th week. Birds from two submissions in this period had severe enteritis, severe diffuse mycosis involving the entire upper alimentary tract (mouth to proventriculus), high ELISA titers to hemorrhagic enteritis virus, and extensive lesions of vitamin A deficiency (squamous metaplasia) involving mucous glands from mouth to proventriculus, larynx and trachea and the bursa of Fabricius. Absence of feed in crop and gizzard (gizzards contained only litter) suggested starveout and a check of feed tanks confirmed minimal feed consumption. At the peak of morbidity nearly 100% of birds were extremely depressed and down in their legs and some had apparent neurologic signs. Many birds were also severely dehydrated indicating inability to get to waterers. Several attempts at treatment (bacitracin, copper sulfate, etc.) had little effect on mortality. During the 14th week feed bins were emptied and refilled with fresh feed and feed and water was made accessible even to down birds. Mortality dropped from a high of 255 birds per day to normal levels (0-2/day) over the next 10 days. Total mortality approached 2000 birds and many surviving birds were undersized. Feed analysis revealed high peroxide levels confirming rancidity. Vitamin A was undetectable and Vitamin E levels were very low. Birds from the final submission at 13 weeks had undetectable levels of Vitamin A in liver and barely detectable (0.3 to 0.4 ppm wet weight) levels of Vitamin E. |
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