The viscoelasticity of blood and plasma in pig, horse, dog, ox, and sheep.

The research article investigates the viscoelasticity or ‘stickiness’ of blood and plasma in five different animal species – pigs, horses, dogs, oxen, and sheep. It reveals that pigs have the highest blood viscosity, followed by horses, dogs, oxen, and sheep, respectively. The differences could be attributed to the varying hematocrit levels and the unique blood cell aggregation trends in each species.

Methods and Findings

• The researchers used an in-vitro method involving oscillatory flow to compare the viscoelasticity of blood and plasma in the five animal species.
• They observed that at shear rates ranging from 1 to 150/sec, the viscous and the elastic component of complex blood viscosity was highest in pigs, then horses, dogs, oxen, and sheep in decreasing order.
• Additionally, the viscosity and density of plasma were found to be similar in dogs and sheep but higher in oxen.

The Role of Hematocrit and Aggregation

• The study noted that the differences in whole blood viscosity among the different species could be attributed to variable hematocrit levels. Hematocrit refers to the percentage of red blood cells in the blood, which affects its viscosity or ‘stickiness’.
• Another factor influencing blood viscosity could be the varying tendencies of blood cell aggregation in different species. Aggregation refers to the clustering of blood cells, which could affect the flow and viscosity of blood.

Implications of the Study

• The research may suggest that due to the relatively dense plasma and separately suspended erythrocytes, sheep and oxen are less likely to form microthrombi, or small blood clots, in comparison to pigs, horses, and dogs.