Pathomorphology of diarrhea in newborn calves
Diarrhea of newborn calves takes an important place in the morbidity in young cattle. The aim of the study was to establish pathogenetically significant morphological changes in the organs and tissues of newborn calves with diarrhea. After an external examination of the corpses, an autopsy and a macroscopic examination of the organs was carried out with the preparation of smears-prints and their staining according to Gram. The pathological material was fixed in 4% neutral formaldehyde solution, Carnoy's liquid and cold acetone. Sections were obtained from paraffin and frozen blocks on a rotary and sled microtome. The sections were stained with hematoxylin and eosin, as well as using the Van Gieson method. Nucleic acids were detected by gallocyanin-chromium alum according to Einarson, total protein - by bromophenol blue according to Bonheg's method, neutral fats - by Sudan III according to Herxheimer. Glycogen and neutral glycosaminoglycans were determined using the periodic acid Schiff reaction according to the Shabadash method, acidic glycosaminoglycans - by Steadmanʼs alcian blue. To determine the activity of alkaline phosphatase, the Gomori method was used. Histo-examination revealed vascular and dystrophic changes in the organs. Loosening and swelling of the connective tissue based on the submucosal and muscular layers was noted in the proventriculus. In the abomasum, the pyloric glands were short, with weak branching. In the duodenum, in some areas, the villi and glands do not have a clear structure, the swollen epithelium is rejected from the basement membrane. In the small intestine, edema of the own and submucous layers of the mucous membrane is observed. In the gastrointestinal tract, the activity of alkaline phosphatase sharply decreases, RNA synthesis is disrupted, and the amount of glycosaminoglycans increases. The presence of microorganisms in smear-imprints of parenchymal organs has not been established. The results of the study indicate the directions of the search for means of pathogenetic therapy.