# Anatomical View of the Internal Carotid Artery Occlusion in Japanese Black Cattle

## TL;DR

This study examines the presence and occlusion of the internal carotid artery in Japanese black cattle across different ages.

## Contribution

The study provides new anatomical insights into the internal carotid artery occlusion patterns specific to Japanese black cattle.

## Key findings

- The left internal carotid artery in Japanese black cattle closes after age 3, except for a small lumen at 13 years.
- The right internal carotid artery remains open at all ages examined.
- The occluded left artery shows thickened tunica intima and increased connective tissue.

## Abstract

Japanese black cattle are a well-known Wagyu cattle breed in Japan, with the best-producing carcass. Based on previous studies and the literature, the existence of the internal carotid artery in cattle still needs to be determined. Thus, this research examined the arterial supply in the brains of Japanese black cattle, especially the presence of the internal carotid artery and its closure at different ages.

The internal carotid artery (ICA) is a branch of the common carotid artery (CCA), along with the external carotid artery (ECA), which together provide the blood supply for the brain. The description of the ICA in cattle is vague, including denial of its existence or degeneration at an early stage after birth. This anatomical study investigated the internal carotid artery in Japanese black cattle. Sixty-five heads of Japanese black cattle aged from newborn to 13 years were dissected and injected with colored latex from the CCA after separating the head and body. Diameter measurements of the artery branches from the CCA on its bifurcation were conducted. Furthermore, a histological examination of the ICA wall’s structures, which consist of the tunica intima, tunica media, and tunica externa, was performed. The ICA of Japanese black cattle is closed on the left side after age 3 years, except for a small lumen at 13 years, whereas the right ICA remains open at all ages. The location of occlusion of the left internal carotid artery (LICA) shows thickness of the tunica intima and an increased connective tissue layer area. The diameter of the ICA does not differ between the left and right sides, and there is no correlation with age. Therefore, further studies are needed, especially of ICA occlusion related to Japanese black cattle’s physiology or cerebrospinal disease.