Dr. S. P. IngoleSHIVESH KUMAR DESHMUKH2024-07-192024-07-192024https://krishikosh.egranth.ac.in/handle/1/5810212278The present study was conducted on 36 samples of mammary gland of Kosali cows procured from central plain region of the Chhattisgarh and divided into two groups - lactating and non-lactating/ non-pregnant stages with 18 cows in each group. Lactating and non-lactating/ non-pregnant stages were further categorized as early, mid and late groups, each with 6 animals. After recording gross parameters, the tissue samples were processed for histological, histochemical and ultrastructural studies. Grossly, the udder of lactating Kosali cow was large and bowl shaped, whereas it was small and round in non-lactating/ non-pregnant Kosali cows. Teat of Kosali cow was cylindrical or conical shaped in lactating and funnel or pear shaped in non-lactating/ non-pregnant Kosali cow. The rear quarter teats were shorter and thicker than the front teats in lactating as well as non-lactating/ nonpregnant cows. Distance between front teats was higher as compared to rear teats in both the groups. Histologically, the mammary gland was ensheathed by the skin and capsule from outside to in. Glomus organs were observed in the reticular layer of dermis of the skin in both stages of cows. The amount of interalveolar, interlobular and interlobar connective tissue increased in mid and late lactation to dry stage and was maximum in late nonlactating/ nonpregnant cows. Varied ii shaped lobules containing alveoli of different shape and adipose tissue were found. The percentage of small alveoli showed increasing trend, while medium and large alveoli decreased from lactating to non-lactating stage. The alveolar epithelium changed from high cuboidal in early lactation to squamous in late nonlactating stage. The duct system was lined by low cuboidal with patches of bistratified cuboidal in lactating and low cuboidal to squamous in nonlactating cows. “Corpora amylacea” were intra alveolar in lactating stage and were found, mostly in stromal connective tissue non-lactating cows. Myoepithelial cells were more in non-lactating Kosali cows. Epithelium of gland cistern was high cuboidal in lactating and low cuboidal in non-lactating stage. The degenerating rudimentary lobules were ten to twenty times smaller in non-lactating stage. In annular fold region, the epithelium was high cuboidal in lactating and low cuboidal in non-lactating cows. In lactating stage, the glandular lobules were approximately three time larger in size than non-lactating stage. The lining epithelium of teat cistern was mostly cuboidal with patches of bistratified cuboidal and columnar in lactating and non-lactating Kosali cows. Mucosa showed mostly circular folds in lactating and longitudinal folds in nonlactating stage. The stratum corneum of the epidermis was apparently two times thicker in lactating than non-lactating stage. Mucosal folds of Furstenberg’s rosette were primary as well as secondary. In both stages, Furstenberg’s rosette was lined by cuboidal, bistratified cuboidal and stratified squamous nonkeratinized epithelium. Furstenberg’s rosette associated lymphoid tissue (FALT) were present in diffuse and dense form as lymphoid follicles. The teat iii canal was lined by a stratified squamous epithelium in initial part, distally keratinization was increased. All the gross and histomorphometrical parameters except thickness of capsule of different regions of mammary gland were significantly higher in early lactation as compared to mid and late, in lactating Kosali cows and were significantly higher in early dry period as compared to mid and late, in nonlactating Kosali cows. Further, they were significantly higher in lactating as compared to non-lactating cows in early, mid and late stages. The percentage decrease in the above parameters between mid and late stages was higher (60%) as compared to early and mid stages (40%) in lactating as well as non-lactating Kosali cow. Average diameters were increased orderly from mammary alveoli to intralobular duct, interlobular duct, and lactiferous duct. Average diameters of teat canal were higher at orifice than midpart and near the rosette of Furstenberg. Histochemically, collagen was the most abundant fiber followed by reticular and elastic. Their density was apparently increased with advancement of lactation from early to late stage. These fibers were more compact and denser in non-lactating/ non-pregnant Kosali cows. In the capsule and connective tissue stroma, PAS positive reaction was intense in lactating Kosali cows and moderate reaction in non-lactating/non-pregnant cows. Moderate to intense reaction for PAS positive material was noticed in epithelium, intraluminal secretions, basement membranes and smooth muscles of alveoli and duct system in lactating group, whereas weak reaction was found in non-lactating Kosali cows. Epithelium of alveoli, and duct system of lactating cows showed mild to moderate reaction and basement membrane and secretory material showed strong reaction for acid iv mucopolysaccharides in lactating mammary gland. In non-lactating gland, it was mild. Corpora amylacea was moderately PAS positive in non-lactating and intensely positive in lactating Kosali cows. Epithelium of gland cistern and annular folds, teat cistern, rosette of Furstenberg and teat canal were positive for PAS and AB-PAS reactive substances in both the groups but reaction was weak in non-lactating group. Ultra-structurally, three types of cells were seen in mammary alveoli viz. alveolar epithelial cells, myoepithelial cells and wandering cells. The glandular epithelial cells of lactating Kosali cows were active and polar in nature in lactating stage and became inactive and apolar in non-lactating stage. The amount of euchromatin was decreased and simultaneously heterochromatin increased in proportion with progression in lactation. The cytoplasmic nuclear ratio in alveolar epithelial cells was more in early lactation than in advance lactation. The alveolar epithelial cells of early and mid lactating Kosali cows were densely packed with well-developed cytoplasmic organelles, which were reduced almost thrice in late lactating stage. The luminal border of lactating epithelial cells showed numerous irregular microvilli projecting in the lumen. Three types of stasis vesicles viz. intermediate electron dense/ electron dense/ electron dense with granular protein were noted in the apical portion of cells in the late lactating stage. The alveolar epithelial cells contained two distinct types of secretory material viz. lipid droplets and casein micelle. In early and mid lactating stage casein particle and lipid droplets were almost equal, whereas in late lactation, casein droplet predominated over lipid droplet. The alveolar lumen was either empty or filled with little secretory material in non-lactating/ nonpregnant Kosali cows. v During lactation, the tight junctions of the alveolar epithelial cells were intact and impermeable. The same were loose and leaky during late lactation in non-lactating/ non-pregnant Kosali cows. The corpora amylacea were noted in the alveolar lumen of lactating and nonlactating stage. Dense lamellated corpora amylacea had alternate thin electron dense and thick intermediate electron dense granules arranged in circular fashion. The myoepithelial cells were irregular flattened, elongated to fusiform in shape. In non-lactating/ non-pregnant Kosali cows, the cytoplasmic processes of myoepithelial cells protruded deeper into the underlying stroma. The lymphocyte and macrophages were more prevalent in lactating cows. In nonlactating/ nonpregnant Kosali cows, many macrophages and lymphocytes were observed. Monocytes were also observed at some places.EnglishThesis