Erythrocyte sedimentation rate of Animals
Erythrocyte sedimentation rate (ESR) of Animals is a measure of the settlement of the erythrocytes in millimetre for a given period usually 30 minutes or one hour when citrated blood filled standard hematocrit tube is placed in an absolutely vertical position.
The length of storage of the blood sample and temperature of storage may influence ESR. The ESR test is generally done as part of complete hematological investigations.
Suspension stability or sedimentation of RBCs in the blood is influenced by RBCs and plasma characteristics. Rouleaux formation or the agglutination of RBCs influences the ESR.
Increasing concentration of fibrinogen or the globulin hastens agglutinations of RBCs. ESR is positively influenced by rouleaux formation and plasma contents of fibrinogen, α2 globulins and gamma globulins, while it is negatively influenced by reticulocytes and plasma content of the albumin.
Fibrinogen and a globulin are commonly elevated in variety of inflammatory diseases e.g., pleurisy, pericarditis, peritonitis, whereas hemoconcentration and glomerulonephritis may adversely affects the ESR by altering the influence of albumin fraction.
The speed of settling of RBCs is inversely proportional to the number of erythrocytes in the given sample. Among the domestic animals, the erythrocytes of ruminants show little or low natural tendency to form rouleaux, whereas the equine blood shows high tendency to form rouleaux formation.
Increased ESR is very common in increased cholesterol: lecithin ratio, pregnancy, acute general infections (septicaemia), and rheumatic fever, TB, arthritis, toxaemia, malignant tumours, hypothyroidism and glomerulonephritis. Decreased ESR is seen in afibrinogenemia, polycythemia, allergy etc.
ESR value of Domestic Animals
| ESR (mm) | Cattle | Sheep | Goat | Dog | Cat | Horse | Chicken |
| 30 minutes | — | — | — | 1-5 | — | 15-38 | 0-1 |
| 60 minutes | — | — | — | 6-10 | 7–27 | — | 1 – 3 |
Note
The ESR merely helps in evaluating the health status of animals, but it is not helpful in diagnosing any specific diseases.
Factors influencing ESR
Size and shape of erythrocytes, specific gravity of erythrocytes, specific gravity of plasma, viscosity of plasma, fibrinogen and globulin content, temperature are the factors affect ESR.