Discipline: Animal Science
This study described the topographic anatomy of the facial vein in the Philippine water buffalo. Its possibility as an alternative site for blood collection for routine hematological examination was determined. Hematological values included packed cell volume (PCV), total red blood cell (RBC) and white blood cell (WBC) counts, differential WBC count, coagulation time and bleeding time. The facial vein was a branch of the linguofacial vein. After emerging from the ventral border of the mandible, it gave off, in correct order the inferior labial vein, superior labial vein, lateral and dorsal nasal veins, and frontal vein. The outlines of vessels were visible in live animals. The facial vein and its branches were accompanied by arteries. The definition of the facial vein and its branches was poor when the head was raised and improved when lowered. Blood collection from the facial vein was possible but difficult because of head movements. The facial vein can be raised through application of digital pressure at the ventrolateral aspect of the mandible. The PCV from the facial vein was 30.4±5.04%; total RBC, 3.1±0.45 x 106 cells/ml; total WBC, 8.2±0.58 x 103 cells/ml; segmented neutrophils, 49.5±5.36%; lymphocytes, 5.2±5.44%; monocytes, 1.1±0.25%; clotting time, 4.6±0.94 min; and bleeding time, 1.7±0.51 min. These values were different from those reported from other blood vessels. Because of the resistance offered by the animal and the fact that only a small amount of blood can be collected from the facial vein, the vessels normally used for blood collection such as the external jugular vein, median caudal vein and lateral caudal vein should be used especially when collecting larger amount of blood.