Changes in plasma enzyme activities and other blood components in response to acute and chronic liver damage in cattle.

Three calves were dosed orally with carbon tetrachloride at 0.05, 0.1 or 0.3 ml/kg body-weight. Plasma enzyme activities, clotting times, bilirubin concentrations and bromsulphthalein elimination times increased. These changes are associated with damage to the liver and are discussed in relation to the clinical syndrome. Three groups of seven calves were infected weekly with 10, 50 or 100 Fasciola hepatica metacercariae for 12 consecutive weeks. Maximum glutamate dehydrogenase and gamma glutamyltransferase activities in the plasma were greater with the larger infecting doses but there was no change in plasma clotting times.

Effect on calves of barley naturally contaminated with ochratoxin A and groundnut meal contaminated with low concentrations of aflatoxin B1.

Four groups of six 12-week-old male Friesian calves were fed diets containing 390 to 540 microgram ochratoxin A per kg, 320 to 500 microgram ochratoxin A plus 12 to 13 microgram aflatoxin B1 per kg, 10 to 13 microgram aflatoxin B1 per kg, or a control diet containing neither toxin. At the end of the 87-day experiment there was no evidence of kidney or liver damage in any group of animals as judged by serial plasma and urine enzyme assays, haematological examinations including the assay of blood coagulation factors, gross appearance at autopsy or histopathological assessment at the light microscopic level. Nor was there any significant alteration in serum IgA, IgM, IgG1 and IgG2 levels or in titres to environmental bacterial and viral antigens. Trace amounts of ochratoxin A were detected in kidneys of five out of the 12 calves exposed to this toxin but all 12 kidneys contained residues of the metabolite ochratoxin alpha (less than 5 to 10 microgram/kg). Traces of aflatoxin B1 and M1 were detected in the liver of one of the 12 calves exposed to aflatoxin B1 but nine kidneys contained the metabolite aflatoxin M1 (less than 0.01 to 0.03 microgram/kg). There was no evidence of interaction between the two toxins.

Identification of factor XI deficiency in Holstein-Friesian cattle in Britain.

Blood coagulation tests were performed on dairy cattle in a herd with haemorrhagic problems on a farm in Gloucestershire. The characteristic pattern of prolonged partial thromboplastin time with normal prothrombin time and thrombin time was shown to be associated with a partial factor XI deficiency, a congenital defect previously identified in cattle in North America.

Haemorrhagic syndrome of cattle associated with the feeding of sweet vernal (Anthoxanthum odoratum) hay containing dicoumarol.

An outbreak of a haemorrhagic diathesis in cattle fed home produced hay is described. A similar syndrome was reproduced experimentally in calves by feeding them the hay. The experimental disease was characterised by increased prothrombin and partial thromboplastin times while the leucocyte and erythrocyte counts remained normal until the terminal haemorrhage. The calves ate well and grew well until the rapid onset of progressive weakness, stiff gait, mucosal pallor, tachycardia, tachypnoea and haematomata ending in sudden death. The absence of blood coagulation was seen at necropsy while petechial, ecchymotic and free haemorrhages were found in most organs. Particularly striking were massive ecchymotic haemorrhages on the peritoneal surface of the rumen, a bloody, gelatinous mass enveloping each kidney and extensive bruising, haemorrhage and haematomata in the subcutis of the limbs. In a second feeding trial the effects of various preparations of vitamin K1 and vitamin K3 were investigated. Oral administration of large quantities of vitamin K1 reduced the elevated prothrombin time; vitamin K3 acted less consistently. Analysis of the hay for trichothecene mycotoxins was negative but floral analysis revealed that sweet vernal grass (Anthoxanthum odoratum) comprised about 80 per cent of the hay. Dicoumarol was detected in the hay and in the serum and ruminal contents of the experimental calves. The diagnosis, treatment, control and importance of this syndrome in the United Kingdom are discussed.

Biochemical indicators of liver injury in calves with experimental fascioliasis.

Twenty calves were infected with 1000 metacercariae of Fasciola hepatica, the activities of 10 enzymes in plasma or serum were assayed and concentrations in serum of proteins, urea and bilirubin were determined. These values were compared with control data obtained from 14 uninfected calves. Aspartate aminotransferase, lactate dehydrogenase, sorbitol dehydrogenase, glutamate dehydrogenase, ornithine carbamoyl transferase and gamma-glutamyl transpeptidase activities increased in infected calves. Total serum protein increased, albumin decreased, globulin increased and the albumin/globulin ratio was decreased in infected calves. Plasma alanine aminotransferase, leucine aminopeptidase, alkaline phosphatase and cholinesterase activities and serum concentration of urea and bilirubin were unaffected. It was concluded that glutamate dehydrogenase and gamma-glutamyl transpeptidase were the most sensitive indicators of liver cell damage in fascioliasis.

Preferential distribution of streptomycin in pig kidney cortex.

In 14 pig kidneys containing streptomycin, an average distribution ratio of 2.5:1 was found for the streptomycin between the cortex and medulla. It is suggested here that cortex alone be used, instead of mixed kidney tissue, in regulatory meat monitoring schemes.