Goat rib bone marrow thick smear preparation as a low-cost, ethical, and high-utility laboratory exercise for...

The study of hematopoiesis is based on the understanding of precursor cell maturation through various lineage stages. The standard educational approach uses premade slides and digital images because of the limited availability of fresh bone marrow samples and the associated ethical constraints. This laboratory module presents an economical teaching method by using goat (Capra aegagrus hircus) rib marrow obtained from licensed slaughterhouses to demonstrate smear preparation and Romanowsky staining for hematopoietic precursor cell identification. The experimental approach was developed as a potential practical teaching activity for first-year medical students, in accordance with Competency Based Medical Education (CBME). Goat ribs (an animal by-product of meat consumption) obtained from a licensed meat shop were immediately transported to the laboratory and cleaned, and bone marrow was extracted, followed by thick and thin smear preparation, which was then fixed with chilled methanol, air-dried, and stained with Leishman and May-Grünwald-Giemsa (MGG) stains. The smear was examined under an oil-immersion microscope for identification of the blood cell lineages and determination of the myeloid-to-erythroid (M:E) ratio. The method for thick and thin smear preparation consistently produced samples that contained cells with intact morphology. The precursor cells could be identified based on their characteristic morphological features, and M:E ratio was calculated from the smears. The procedure was successfully repeated with consistent smear quality and cellular morphology, indicating that the technique is feasible and reproducible for incorporation into the proposed teaching model.NEW & NOTEWORTHY The present model introduces an active, hands-on learning approach that moves beyond passive slide-based instruction by directly engaging students in laboratory preparation and microscopic analysis. It establishes a sustainable, low-cost teaching resource for physiology laboratories while effectively bridging theoretical concepts of hematopoiesis with their clinical and morphological correlates. Importantly, the method is scalable and well suited for institutions with limited infrastructure, enabling authentic laboratory-based learning experiences without reliance on scarce human samples.