ANEMIA AND POLYCYTHEMIA
1. Define anemia and polycythemia.
2. Without supplemental iron, why would anemia be common in baby pigs?
3. Differentiate between absolute and relative polycythemia.
4.
What are some primary conditions that cause absolute polycythemia?A reduction in the number of erythrocytes, the concentration of hemoglobin, or both is referred to as anemia, which can have several causes. It is called a functional anemia if erythropoietin production is not stimulated because of lack of exertion, whereby the tissues do not become hypoxic. Blood loss for any reason (e.g., trauma, parasitism) can also cause anemia. A common type of anemia in baby pigs is iron-deficiency anemia. This type is common in baby pigs because of their rapid growth and consequent need for greater blood volume, and also because of the lack of iron in their normal diet, which is sow’s milk. Because of iron deficiency, an insufficient quantity of hemoglobin is produced. Anemia can also occur from poor erythrocyte production, such as when certain nutritional factors are missing or if the bone marrow has been poisoned. This latter type is known as aplastic anemia.
A condition opposite to that of anemia is polycythemia. In this condition, the erythrocyte mass is greatly increased. The condition may be relative or absolute. In relative polycythemia, there is an increase in red cell mass and a decrease in plasma volume. This is commonly encountered in conditions of shock and dehydration and in animals being treated with diuretic or cardiac medications. Absolute polycythemia is associated with an increased red cell mass without a decrease in plasma volume. It is secondary (not the primary condition) if associated with hypoxemia (decreased O2 in arterial blood) or a tumor because either condition increases erythropoietin production. In the absence of hypoxemia or tumors, and when erythropoietin concentrations are normal or decreased, the.condition is classified as a myeloproliferative disorder (increased bone marrow production) or polycythemia vera. Polycythemia vera is rare in animals, although it has been described in cats, dogs, and cattle.
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