Increased concentrations of transferrin in the urine and serum of cattle with cardiomyopathy

Bovine and canine transferrin inhibit the growth of Malassezia pachydermatis in vitro

Transferrin, an iron-binding beta-globulin protein that transports iron to mammalian cells, may contribute to innate immunity to fungal pathogens, primarily by limiting microbial access to iron. We investigated whether unsaturated (apo) canine and bovine transferrin had an inhibitory effect in vitro on Malassezia pachydermatis, an important opportunistic cutaneous yeast pathogen of dogs. M. pachydermatis strains were grown at 32 degrees C in 96-well culture plates using Sabouraud's liquid medium containing canine or bovine apo-transferrin at concentrations ranging from 10.6 to 0.7 mg/ml. Optical densities (OD492) in the treated and control wells were measured and then compared between treatments. Bovine and canine transferrin inhibited (P < 0.01) yeast growth at all concentrations tested after five and six days of incubation; inhibition by 5.3 mg/ml exceeded (P < 0.05) that of 0.7 mg/ml on day six. Unsaturated and saturated bovine transferrin had comparable inhibitory effects on the growth of four strains, indicating that the inhibitory effects of transferrin on M. pachydermatis are not dependent upon iron depletion. These studies suggest that transferrin may contribute to innate immunity to M. pachydermatis in dogs and cattle.

Clinical and pathological features of dilated cardiomyopathy in Holstein-Friesian cattle

Dilated cardiomyopathy is a primary disease of the heart muscle that has been reported in Holstein-Friesian cattle worldwide in the past 20 years. Nine cases of the condition were compared in terms of their clinical and pathological characteristics with nine unaffected animals matched for age, sex and breed. Their clinical signs included right-sided heart failure with severe subcutaneous oedema, ascites and/or hydrothorax and distended jugular veins. There were no characteristic biochemical or haematological changes. Postmortem, the affected hearts were enlarged with all the chambers dilated and walls of variable thickness. In most cases the kidneys were pale with a pitted surface. Histologically there was marked perimysial and endomysial fibrosis, extensive loss of cardiomyocytes by coagulative or colliquative necrosis, increased variation in the cross-sectional area of the myocardial fibres, and multifocal disarray and vacuolation of myocytes. Scanning electron microscopy showed that in all cases there was a mild myocardial inflammatory infiltrate, either diffuse or multifocal, which was identified by immunohistochemical labelling as T cells.

Bovine serum transferrin concentration during acute infection with Haemophilus somnus

A novel, competitive immunoassay based on time-resolved fluorimetry was developed, and used to measure the serum concentration of bovine transferrin during acute Haemophilus somnus pneumonia. Upper and lower limits of normality were established using serum from healthy cattle (3.72-1.37 mgmL-1). Following experimental infection with Haemophilus somnus, transferrin concentration was depressed in all calves but recovered to pre-infection levels in groups of calves which had either no lesions, or mild lesions at necropsy between 5 and 6 days after infection. In a third group, which developed extensive lesions, the transferrin concentration remained depressed. Transferrin levels remained within the normal range for all calves during the experimental period. Those calves which had low transferrin concentrations pre-infection, developed extensive lung lesions following experimental infection with Haemophilus somnus.