Toxic form of steatosis in dairy cows (clinical, hematological and histological data)

Abstract

Steatosis is a common disease in dairy cattle, especially during the transit period. Usually, the subclinical form of hepatosis is evenly distributed in the population throughout the year: 30‐70% of cows can be affected. However, severe (toxic) steatosis is rare. The study was carried out on 505 dairy cows in the North‐West of Russia in July‐August. In the blood serum, the concentrations of the main substances were investigated, and the morphological examination of the blood was carried out. Liver samples for histological examination were collected posthumously. 47% of cows had subclinical hepatopathy, 1.78% (9 cows) ‐ a toxic form of steatosis. Clinical signs of severe hepatopathy were observed from 1 to 10 days after calving: anorexia, icterus, ventroflexia, excitability, convulsions, exophthalmos. In the blood: total protein 59.8±0.9 g/l, albumin ‐ 35.1±2.5%, total bilirubin ‐ 23.8±0.8 μmol/l, triglycerides ‐ 0.329±0.01 mmol/l, cholesterol ‐ 8.7±1.0 mmol/l, RBC 3.9±0.1*1012/l, PLT ‐ 190.1±39.8*109/l, WBC ‐ 8.36±0.75*109/l, HCT – 29.1±0.5%. Autopsy: icterus of the mucous membranes, petechiae in the kidneys, intestines, brain membrane, injection of blood vessels, enlargement of the liver and kidneys, the liver capsule breaks easily, the parenchyma is loose. Liver’s parenchyma imprint smears: staining with Saathof solution ‐ much neutral fat. Rumen: detachment of the mucous membrane. Liver: large and small vacuole diffuse fatty infiltration of hepatocytes, thickening of the portal tracts with expressed mononuclear infiltration. The liver has an ordered lobular structure, is moderately full‐blooded, the sinusoids of the liver and the Disse spaces are moderately dilated, staining with Schiff‐iodic acid according to McManus ‐ the absence of glycogen in hepatocytes. Kidneys: hyaline‐drop dystrophy of the epithelium of the renal tubules, fibrosing interstitial glomerulonephritis. Rumen: the mucous membrane forms convex structures of the main plate of various sizes and shapes, covered with multilayer squamous epithelium; there are areas of degeneration. The muscle plate was formed by separate bundles of smooth myocytes lying at the base of the papillae; individual muscle cells were found in the main plate of the papilla. The plate consisted of an inner annular and an outer longitudinal layer of smooth muscle cells, among which there were individual fibers of striated muscle tissue. The serous membrane of the rumen had a typical structure; it was represented by loose connective tissue covered with mesothelium. According to the results of this study, it was revealed that the toxic form of hepatosis is accompanied by multiple organ failure: an expressed violation of the nervous system, hypoprotein‐, dysprotein‐, hyperbilirubin‐ and anemia, large and small‐drop fatty infiltration of hepatocytes, glomerulonephritis, lesions of the rumen and intestinal wall.