Feedyard dust induced a temporary febrile response and leukocytosis in sheep in the treatment group. Exposure to dust that contains endotoxins may be a stressor preceding acute infectious respiratory tract disease of marketed sheep.

Abstract. Hair, peripheral blood leukocytes, and other tissues from two related Brangus calves with phenotypic characteristics of Chediak-Higashi syndrome were examined by light and electron microscopy. Enlarged, pleomorphic, cytoplasmic granules, morphologically compatible with lysosomes, were seen in several neutrophils, many eosinophils, renal tubular epithelial cells, and Kupffer cells. Hair shafts of the calves showed irregular distribution and clumping of melanin granules. Severe infection and a possible hemorrhagic tendency were recognized. These Brangus calves represent the third breed of cattle affected with this genetic disease.Chediak-Higashi syndrome (CHS) is a genetic disease occurring in man,2s26 mink,I5 cattle,I5 beige (CHS) mice,6 cats,g killer whales,23 and f o x e~.~J~ CHS is manifested by partial oculocutaneous albinism, photophobia, marked susceptibility to infection~,'~ platelet pool storage deficiency,' lack of natural killer cell activity,21 impaired microtubule function, l4 and the occurrence of large pleomorphic granules in the cytoplasm of leukocytes, and most, but not all, granule-producing cell^.^^^ Many of these enlarged granules have ultrastructural and cytochemical characteristics of 1ysosomes.8 The granules in neutrophils and eosinophils are strongly peroxidase-positive or Sudan Black B-positive.2 The enlarged granules in CHS cells often stain positively with periodic acid-Schiff (PAS).I3J7 CHS was originally described in Hereford cattle as being characterized by abnormal leukocytes, hypopigmentation, and increased susceptibility to disease, conditioned by an autosomal recessive gene.16 All CHS cattle reported were incomplete albinos, with gray irises instead of the normal dark brown to black. Several had hemorrhagic tendency, and melanin granules were scant in the skin. Comparative studies of CHS and non-CHS cattle have demonstrated the presence of PAS-positive granular inclusions in renal tubular epithelium of CHS but not non-CHS cattle.I7An 8-month-old female Japanese black heifer diagnosed as affected with CHS was reported to have the following lesions: growth retardation, brownish skin and hair, and enlarged granules in the cytoplasm of all eosinophils and basophils. Similar granules were seen less frequently in all other granulocytic leukocytes except the monocyte. Many inflammatory changes were present in various organs and tissues. Histological and ultrastructural findings of eosinophilic or brownishyellow pigment in the neurons and renal tubular epithelium coincided with those previously reported in CHS.24This study describes ultrastructural and light microscopic studies of hair, leukocytes, and other cells of two related Brangus calves with phenotypic and microscopic characteristics of CHS.This study was done as a service to people in the livestock industry to help make them aware of the negative economic implications associated with genetically transmitted disease. Materials and MethodsThe occurrence of related Brangus calves affected with a pigmentary deficiency was br...

The objective was to determine whether the inhalation of large quantities of feedyard dust predisposed the animals to pulmonary bacterial proliferation. Two control groups, C1 and C2, did not receive dust treatments, and two principal groups (P1 and P2) received a total of 14 dust treatments each. The C1 and P1 groups of goats each received a transthoracic challenge of live Mannheimia haemolytica (4 x 10(6) colony forming units, CFU) The C2 and P2 groups of goats each received a transthoracic challenge of live Pasteurella multocida (1.0 x 10(6) CFU/goat). The results showed that dusted animals had fever when compared with non-dusted controls. In addition, dusted animals demonstrated a leukocytosis with neutrophilia after the first dust treatment that was not sustainable. Finally, dusted animals demonstrated pulmonary clearance of two potential bacterial pathogens that was not significantly different from that shown by control (not dusted) animals.

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