The histomorphological studies on ontogeny of Peyer's patches in jejunum of 20 buffalo fetuses ranging from 11.5 cm CVRL (80 days) to 100 cm CVRL (299 days) were conducted. The fetuses were categorized into three groups based on their curved crown rump length (CVRL). The fetuses of gestational age from 11.5 cm CVRL (80 days) to 28 cm CVRL (136 days) were devoid of typical jejunal lymphoid patches. However, at 32 cm CVRL (145 days) aggregates of 2 to 3 lymphocytes were observed arranged linearly in submucosa of jejunum Elongated to oval lymphocytic aggregations were observed in submucosa at 54 cm CVRL (195 days) that formed primordia of lymphoid follicle. The presence of darkly stained lymphocytes was also observed in the intestinal villi above the aggregates at this stage. At 70 cm CVRL (231 days), a number of round, pear shaped developing lymphoid follicles were encountered. At 100 cm CVRL (full term), completely developed lymphoid follicles of different shapes i.e., oval, pear shaped and square shaped follicles were present that were arranged in a single row on the anti-mesenteric part of jejunum. The dome of lymphoid follicle was completely formed at this age by invading the jejunal villi that formed arcs over it. Therefore, the present study suggests that the jejunal Peyer's patches started its development at mid-gestational age and become completely developed in the fetuses that reached upto full term just before birth. Thus these jejunal Peyer's patches generates immune response by sampling foreign antigens entering the lumen and play a crucial role in terms of generating mucosal immunity.

The present study was conducted on placentomes of 20 buffaloes (n=20) ranging from 38 to 243 days of gestation. Their gestational age was determined by measuring the curved crown rump length (CRL) of foetii using an inelastic thread as per formula given by Soliman (1975) in bovines. Depending on the CRL and estimated age of the foetuses, the samples were divided into 3 groups. The placental tissues fixed in 10 percent NBF were processed and stained accordingly. The present observation revealed that the cryptal epithelium was cuboidal during early and mid pregnancy but transformed to squamous during late pregnancy especially at the tip of the maternal septa. This reduction in size and nature of epithelium during late pregnancy was in order to shorten the distance between foetal and maternal tissue for substance exchange by diffusion. The trophoblastic epithelium transformed from cuboidal during early and mid pregnancy to stratified epithelium in the arcade region due to accumulation of binucleated giant cells that were involved in phagocytosis of extravasated erythrocytes in the arcade region. The phagocytosis released iron from the RBC that were probably being utilized by the developing fetus as very strong reaction for acid phosphatase was observed in the arcade region and iron in the form of fine granules were observed by special staining.

The present study was conducted on 10 buffalo foetii ranging from 13.5 cm CVRL to 98 cm CVRL (89 to 295 days). After collection the tissue samples were processed for transmission electron microscopy. The efferent ductules of buffalo foetii were lined with simple columnar epithelium with ciliated and non-ciliated cells. The ciliated cells were few in number in comparison to the non-ciliated cells. The ciliated cells were characterized by presence of cilia on apical surface with typical 9+2 arrangement and their basal bodies just beneath the apical plasma lemma. Whereas the non-ciliated cells were devoid of cilia. The supra-nuclear cytoplasm of non-ciliated cells contained many coated vesicles. In the later stage of development some migratory intraepithelial and peritubular leukocytes were also observed. The tight junctions found to be poorly developed in the epithelial lining of efferent ductules at 13.5 cm CVRL (89 days) and were well developed at 19.5 cm CVRL (116 days) onwards. In early stage of development efferent ductules were surrounded with the mesenchymal tissue which after condensation differentiated into smooth muscle cells in later stage of development.