Abstract:

To investigate the death causes of cloned Holstein bulls, we compared major tissues and organs of the neonatal-death cloned holstein bull and natural propagation Holstein bull calf. We observed and analyzed the main tissues and organs by anatomy and HE (hematoxylin-eosin staining) staining. The results showed that the lung structure of the neonatal-death cloned Holstein bull was clear. Its liver cells were obviously swollen and the liver had slight degeneration. The renal tubular epithelial cells of the kidney had slight degeneration. The interstitial space between the myocardium fibers was enlarged. Skeletal muscle fiber gap was obvious, and vacuolar degeneration, which might lead to muscle weakness and insufficiency of the cloned bull. The boundaries of the lymphoid cortex and medulla were not distinct. Lymph node cells were sparse, germinal center was not obvious, and lymphatic sinus cells were less. There were fewer red blood cells in the spleen, which might indicate that the cloned bull had imperfect hematopoietic function. The boundary between the cortical and the medulla of the thymus was not obvious. The eosinophilic thymus gland was not easily identifiable and might be hypoplasia. The cloned Holstein bull’s immune organs had different degrees of hypoplasia, which might be the main reason for the high mortality after birth.

Key words: somatic cell cloning, organ abnormality, histopathology, neonatal death, Holstein cow