Hepatic Failure and Hemochromatosis of Salers and Salers-cross Cattle

Abstract

Abstract. Hemochromatosis is rare in domestic mammals. Five clinical cases and one preclinical case of hemochromatosis were diagnosed in Salers and Salers-cross cattle. Clinical disease developed between 9 and 22 months of age. Animals were healthy until weaning but then lost weight, developed rough hair coats, and lost incisor teeth. In two animals, hemochromatosis was identified by liver biopsy, biochemical evidence of hepatic injury, and/or elevated transferrin saturation values. At necropsy, carcasses were thin, with firm dark brown livers and lymph nodes, soft bones, and brown-colored small bowel. The principal histologic changes were hepatocellular siderosis and periportal, bridging, and perivenular fibrosis. Siderocalcinosis involved collagen, elastin, reticulin, and basement membrane components in liver, lymph nodes, spleen, duodenum, and kidney. Hepatic iron concentrations in clinically affected cattle were 1,500-10,500 g/g wet weight (reference range for cattle ϭ Ͻ300 g/ g). Ultrastructurally, the heaviest intrahepatic deposition was in hepatocytes, which contained large intracytoplasmic siderosomes. Iron deposition in bone was associated with osteopenia. Genetic analysis indicated a common ancestral bull in the pedigrees of five of six affected cattle; no pedigree was available for the remaining animal. Four dams of five affected animals were phenotypically normal and had histologically normal livers. Test mating of four cows to the ancestral bull resulted in a female calf that developed clinicopathologic and histologic evidence of preclinical hemochromatosis by 40 days of age. It was not possible to establish the pattern of inheritance because of the small number of pedigrees from affected cattle.

Skeletal Changes in Hemochromatosis of Salers Cattle

“…16,20 A fibro-osseous periosteum with adherence of the skin to the skull has also been noted. 16 One 22-month-old animal with slightly discolored and more pliable skull bones had layers of poorly mineralized porotic bone in the outer cortex of the rib and an elevated iron content in the bone.…”

“…16 One 22-month-old animal with slightly discolored and more pliable skull bones had layers of poorly mineralized porotic bone in the outer cortex of the rib and an elevated iron content in the bone. 20 The affected Salers heifer studied in this report had 4ϩ iron accumulation in the liver, based on Conn's 4-point histologic grading system (0 ϭ no stainable iron; 4ϩ ϭ large iron-positive granules in virtually all hepatocytes), with no detectable hepatic fibrosis or necrosis. Pale islands of less-dense matrix (outlined by arrowheads) and bands of darker, immature matrix (outlined by arrows) were seen in concentric layers beneath the surface.…”

“…Hepatic iron concentrations in both animals were determined using inductively coupled plasma atomic mass spectroscopy as described previously. 20 …”

“…16,20 Clinically, there is an extended clinically silent period (6-12 months), followed by a wasting syndrome associated with hepatic failure. The condition has similarities to human hemochromatosis, which is associated with mutations of the gene for HFE.…”

“…11 This is a protein that complexes with transferrin, and mutations are thought to allow increased iron uptake and storage in parenchymal cells. Loss of incisors and soft bones has been reported in some cattle with hemochromatosis, 16,20 but bone lesions have not been studied in detail.…”