Post-natal development of some lymphoid organs of West African Dwarf (WAD) goats : a histological perspective

Abstract

The study evaluated the developmental changes in the mesenteric lymph nodes, thymus and spleen of West African Dwarf (WAD) goat using histological techniques. Twenty-seven WAD goats of 1 day, 2 weeks and 1 to 7 months old were used for this study. Results showed that the mesenteric lymph node of the WAD goats had poorly organized cortical and medullary areas at 1 day postnatum, and dense infiltration of lymphocytes in the cortex with a few primary lymphoid follicles at 2 and 3 months. At 1 day old, the thymus exhibited thin cortical parenchyma and extensive medullary areas. The thymic parenchyma of 3 and 4 months old showed distorted outlines of the cortex and medulla with adipose tissue deposition in the trabeculae. The number of Hassal’s corpuscles increased from the 1st day to the 7th month of birth. Furthermore, at 1 day old, the spleen demonstrated poorly defined red pulp and white pulp areas. The outlines of the red and white pulp areas were more obvious at 2 weeks of age and the red pulp areas became more expansive with increased concentration of red blood cells from 1 to 7 months old. It was concluded that the mesenteric lymph nodes of WAD goats may attain adult morphology as early as 1 month after birth, the thymus which appeared as a fully functional thymus at birth could regress at 3 months after birth and the spleen could perform limited lymphoid functions immediately after birth.