Characteristics of structural and functional changes the cortex of internal organs in different age periods

The scientific literature provides insufficient data on the development of age-related structural and functional changes in cattle. Studying age-related pathomorphological changes in cattle will help identify markers of premature organ aging and develop strategies and tactics for increasing the productive longevity of cows. The aim of this study was to examine the characteristics of structural and functional changes in the internal organs of mature cattle across age-related factors. Material was obtained from heifers and culled high-yielding cows aged three, four, five, six, and nine years. Organ samples were collected for histological examination and fixed in 10% buffered neutral formalin. Deparaffinized sections 3–4 µm thick were stained with dyes for histological examination. It was established that structural and degenerative changes in organ tissues begin to develop as early as three years of age, that is, after the first calving. The cardiovascular system, which bears the greatest strain from lactation, is primarily affected by these changes. With increasing age, structural and functional tissue degeneration processes intensify: connective tissue proliferation intensifies in the heart muscle, fibrous changes develop in the liver alongside fatty degeneration, and significant hemosederin deposition is detected in the spleen, indicating premature cell senescence. Histological specimens of the hearts of 5- to 8-year-old cows revealed necrosis of the Purkinje fibers, indicating disruption of the cardiac conduction system due to severe degenerative processes. Parenchymatous organs are characterized by changes in the vascular bed and active collagenization of the organ stroma. Thus, cellular aging produces similar morphological changes and has a significant impact on tissue structures.

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