The effect of blocking the angularis oculi and the facial veins on metabolism of Tswana goats

Abstract

The aim of this study was to compare changes in resting metabolism of Tswana goats as a result of diverting venous blood to and away from the cavernous sinus. Eighteen male yearlings were equally and randomly assigned to three groups: A non-operated control group (NOC), a facial vein blocked (BEV) group and an angularis oculi veins blocked group (BAOV). Resting metabolism was measured by an open circuit calorimetry system using a face mask. At the ambient temperatures (Ta) of 160C resting metabolic rate of the NOC group was significantly higher (p-0.014) than for the BOAV group but not significantly higher (p=0.303) than for the BFV group. At the Ta of 25 ° C resting metabolic rate of the NOC group was significantly higher (p=0.006) than for the BAOV group but not significantly higher (p=0.62) than for the BFV group. It appears that heat exchange at the carotid rate-cavernous sinus complex contributed significantly to the control of metabolic rate in the Tswana goats under non heat stressful conditions. Diverting blood from the facial veins into the jugular vein had no significant effect on resting metabolic rate under the same test conditions.