How to Treat Anemia in dogs, cats, and other animals?
Anemia is a common clinical finding during clinical practice. It is important to note here that anemia is not a disease itself rather it’s a sign of so many underlying diseases. Anemia is not only common in dogs and cats, in fact, other food-producing animals are also susceptible to anemia. This article will explain each and every aspect of anemia, what can be the causes of anemia in animals, how to diagnose, types, and most importantly how to treat anemia in dogs, cats, and other animals. So let’s get started.
What is Anemia?
Table of Contents
Anemia is a decrease in the oxygen-carrying capacity of blood and is identified by pallor mucosae/conjunctiva, increased capillary refill time, exercise intolerance, and decreased packed cell volume.
Explanation:
Blood is composed of RBCs, WBCs, and Platelets. Every blood cell type has its own unique function. The RBCs are responsible for the transport of oxygen throughout the body cells. If any how the RBCs are lower than the normal level, the oxygen will not be delivered to tissues. This will be assessed by pale mucous membranes or conjunctiva, increased capillary refill time, exercise intolerance, and decreased PCV (packed cell volume).
Causes of Anemia in Animals
In order to understand the causes of anemia in dogs, cats, and other animals, anemia is classified into the following types.
- Depression / Aplastic Anemia
- Hemolytic / Responsive Anemia
- Hemorrhagic / Regenerative Anemia
Depression or Aplastic Anemia
This type of anemia occurs because of a decrease in RBCs or hemoglobin production. Now, what can be the reasons for decreased production of RBCs or Hb? The reasons are listed below
Vitamin and Mineral Deficiencies
The deficiency of cobalt (ruminants), iron (young animals), copper, pyridoxine(calves), and vitamins E, B6, B12, and folic acid (all animals) are mostly associated with Aplastic anemia.
Other Chronic Conditions
Any chronic systemic suppurative conditions, bone fractures, radiation injuries, plant poisoning (Bracken fern), chemical poisoning, parasitic infections (mostly Trichostrongylosis), and neoplasia of bone marrow can also cause depression anemia.
Hemolytic or Responsive Anemia
Hemolytic anemia develops due to the increased destruction of RBCs, which ultimately decreases the total red blood cell mass. It may be seen in various bacterial, viral, and protozoan diseases as mentioned in the table.
| Viral Diseases | Bacterial Diseases | Protozoan Diseases | Rickettsial Diseases | |
| Equine infectious anemia | Leptospirosis | Babesiosis | Ehrlichiosis | |
| Feline infectious anemia | Bacillary hemoglobinuria | Anaplasmosis | ||
| Theileriosis | ||||
Other Causes of Hemolytic Anemia
Mineral deficiency: Phosphorous deficiency in Post Parturient hemoglobinuria
Plants poisoning: Onion, rape, and cruciferous plants
Chemical poisoning: copper in sheep, phenothiazine in horses
Animal poisoning: Snakebite
Immunological disorders: Like autoimmune hemolytic anemia and reactions during blood transfusion can also be the reasons.
Hemorrhagic or Regenerative Anemia
This type of anemia occurs because of the loss of blood cells.
See about hemorrhage can lead to anemia
Pathophysiology of Anemia in Animals
Every anemia has a different specific pathophysiology, depending on its etiology. The net result of acute anemia is a reduction in the blood’s overall oxygen-carrying capacity and tissue anoxia, which lowers a variety of bodily functions and causes peripheral circulatory failure. The reduction in cardiac output in sub-acute episodes causes an increase in heart rate and stroke volume. The effects of chronic anemia are gradual and subtle.
Clinical Findings of Anemia in Dogs, Cats, and Other Animals
The clinical signs of anemia in dogs, cats, and other animals are almost similar. The most obvious signs are:
- Pale mucous membranes or conjunctiva
- Cold extremities
- Poor peripheral blood circulation
- Increases capillary refill time
- Increase heart rate (tachycardia)
- Exercise intolerance
- Weakness, lethargy, and anorexia
- Tachypnea
- Systolic murmurs due to less blood viscosity
- Increase intensity of heart sounds
Clinical Pathology of Anemic Animals
A CBC report can tell a lot about anemia, what can be the causes, how severe anemia is, etc. In a CBC report, the decrease in RBCs, and Hb number is a clear indication of anemia.
In both hemorrhagic and hemolytic anemia, there is an increase in the production of immature RBCs in the blood, which appear granular and stain darker with Methylene blue stain.
In deficiency anemia, the RBC count may be normal, but with low Hb, and a decrease in MCV and MCH. In such cases, the RBCs stain lighter in color without any granular appearance
Note: Melena is an indication the anemia is due to hemorrhages in the GIT tract.
How to Diagnose Anemia in Animals?
Anemia can be diagnosed with the help of clinical signs, history, CBC report, and Bloor smears. Blood smears can help to rule out whether the anemia is due to any pathogen or not.
Blood-born parasites can be detected in blood-stained smears. As mentioned earlier, the various blood born pathogens are responsible for anemia. Now, how a person diagnose which parasite is present in a blood smear? It needs a lot of practice and clinical skills. For ease of detection below are some pictures of erythrocytic parasites.
Babesiosis in Animals | Causes, Treatment, and Prevention
Note: Theileria parasites mostly infect WBCs but also RBCs.
How to differentiate between types of anemia?
The following table is laid out in a simple manner to make it easier to comprehend what kind of anemia the animal has.
| Sign | Hemorrhagic | Hemolytic | Aplastic |
| History of hemorrhage | ✓ | ☓ | ☓ |
| Hemoglobinuria | ☓ | ✓ | ☓ |
| Pallor of mucosae | ✓ | ☓ | ✓ |
| Jaundice | ☓ | ✓ | ☓ |
| Fever | ☓ | ✓ | ☓ |
| Reduction in PCV | ✓ | ✓ | ✓ |
| Pink Plasma | ☓ | ✓ | ☓ |
| Polychromasia | ✓ | ✓ | ☓ |
| Macrocytosis | ✓ | ✓ | ☓ |
| Microcytosis | ☓ | ☓ | ✓ |
| Erythrocytic parasites | ☓ | ✓ | ☓ |
How to Treat Anemia in Dogs, Cats, and other Animals?
In order to treat anemia in dogs, cats, or any animal, there are 3 options, which option has to opt, it depends on what is the cause of anemia? So the treatment protocols for anemic animals are
- Specific treatment according to the primary cause
- Non-specific treatment like a whole blood transfusion
- Other supportive therapy like hematinics and other vitamins etc
Summary
Anemia is a decrease in the oxygen-carrying capacity of the blood. There are various causes of anemia and in order to treat anemia in animals, it’s necessary to rule out the actual cause.
References
(Marry et al,.) Veterinary Hematology, Clinical Chemistry, and Cytology, 3rd Edition. Available full book pdf here
Merck Veterinary Manual, Anemia in Animals, Available here
Naigamwalla, D. Z., Webb, J. A., & Giger, U. (2012). Iron deficiency anemia. The Canadian Veterinary Journal, 53(3), 250-256. Available here
Stafford, J. L. (1961). Iron deficiency in man and animals. Available here