Age-Related Characteristics of Endometrial Glands in Cows

Abstract

Abstract. The study at Akhmet Baitursynov Kostanay Regional University examined the agerelated changes in glandular epithelium in cows' uterine horns. Results showed maximum activity in cows' first calving, followed by a decrease in subsequent calvings and a peak in the fourth and fifth calvings. Optimal indicators were observed during the fourth to sixth calving period. Introduction: The endometrium is a crucial component of the reproductive system in cows, creating the conditions necessary for embryo implantation, placenta formation, and a successful pregnancy. As cows age, metabolic processes undergo transformations: vascularization decreases, the density of glandular structures diminishes, and dystrophic and fibrotic changes occur [1,3]. These factors can impair a cow's reproductive capacity, lowering the likelihood of conception and increasing the risk of embryonic mortality [2,4]. The limited publications on this topic highlight the ongoing need for further research in this area. Purpose of the study: to investigate the functional characteristics of the glandular epithelium of the uterine horns from an age-related perspective based on cytometric analyses. Materials and Methods: Research material: uterine horn tissues from cows obtained at a slaughterhouse. The animals were divided into six age groups: Group 1 (1 calving), Group 2 (2-3 calvings), Group 3 (4-5 calvings), Group 4 (6 calvings), Group 5 (7 calvings), and Group 6 (8 calvings and older). Histological preparations were made using a classical method, with paraffin sections stained with hematoxylin-eosin [5]. Diameters of glands and exocrinocytes were measured. Histopreparations were examined and photographed, and statistical data processed using Excel 2019. Results: The functional activity of uterine body exocrinocytes in cows is highest after their first calving, then declines to the minimum value after second and third calvings. A significant increase is observed by the fourth and fifth calvings, followed by a gradual decrease after the sixth calving. The nuclear-plasma ratio of the uterine body covering layer reaches its maximum in cows during their first calving. The maximum sizes of glands in the right horn correspond to those in the left horn, but only in terms of internal diameter and height. The functional activity of exocrinocytes in the left uterine horn is most pronounced in young animals (2-5 calvings), but at six calvings, their activity is restored. In contrast, the functional activity of exocrinocytes in the right uterine horn reveals a different pattern, with minimal activity in cows with 2-3 calvings and a significant increase in the right horn by the 6th calving.