If you are concerned about a dropping red blood cell count in dogs, it could you have noticed physical signs suggesting anemia in your dog, or it could be your dog’s recent bloodwork came back with low red blood cell count, and you want to learn more about what can be causing it. Perhaps, your dog needs further diagnostic tests to obtain an exact diagnosis and you wish to gather some questions to ask your veterinarian. A low red blood cell count is often not diagnostic per se’, it just tells you that your dog’s level of red blood cells are low, so the next question is, “Why is my dog’s red blood cell count dropping?” Low red blood cells in dogs can occur secondary to other disease processes and therefore often require further evaluation.
Function of Red Blood Cells
Red blood cells are produced by the dog’s bone marrow (the soft center of bones, yes that brownish center found in those bone marrow bones often fed to dogs).
Red blood cells are responsible for carrying oxygen, but what role do they exactly play? Here’s a little insight into their journey.
As your dog breaths, oxygen enters his body and reaches the lungs. In the lungs, hemoglobin, the protein molecule found in red blood cells, picks up the oxygen and travels to your dog’s heart which pumps out the blood and delivers the oxygen to all hungry cells throughout your dog’s body.
Soon, oxygen reaches all of your dog’s tissues and those tissues are therefore happy because they are receiving a good and healthy flow of blood, what’s known as “perfusion.”
How Low is Too Low?
When all goes well, your dog has a certain amount of red blood cells circulating in his body, but when there is a problem, their numbers may lower, but how low is too low?
One of the first ways veterinarians discover a low red blood count is by looking at their numbers from a complete blood count (CBC). The numbers of red blood cells (RBC) in a dog’s blood are important as they provide information on a dog’s over all health.
Normal red blood cell count value in dogs is between 5.6 and 8.7, explains veterinarian Race Foster. This is the number of red blood cells found in a microliter.
However, an easier and faster way to assess numbers of red blood cells is the hematocrit blood test (HCT), also known as packed cell volume (PCV). This test determines the percentage of red blood cells in the dog’s blood. Normal packed cell volume in dogs is generally between 40-59.
Typically a dog is considered anemic when the percentage reaches in the lower 20’s, and when it reaches 10 percent, things get very critical and affected dogs will need a transfusion, explains veterinarian Dr. Louis Gotthelf.
Did you know? The hemoglobin in red blood cells is what gives blood its distinctive red color. If you ever had a chance to look at blood under a microscope, you would see millions of red blood cells.
Signs of Trouble
Anemia is the medical term used to depict a deficiency of red blood cells in the blood. With less circulating blood around, tissues do not receive adequate amounts of oxygen. While in humans a pale look of the face can be indicative of anemia, in dogs we must look inside their mouth.
A dog with anemia will often have pale gums due to the decreased number of red blood cells in circulation. Other signs of anemia in dogs include weakness, breathing fast, fast heart beat, loss of appetite, exercise intolerance, and sometimes, in severe cases, even collapse.
Lowered Red Blood Cell Production
Lowered production of red blood cells can occur secondary to several conditions. Kidney disease may be one of them, considering that a dog’s kidneys are responsible for creating a special hormone known as erythropoietin which commands the dog’s bone marrow to manufacture red blood cells. Kidney disease generally leads to mild to moderate anemia.
When a dog is affected by kidney disease, this hormone is no longer produced as it should, leaving the dog with a reduced production of red blood cells.
Red Blood Cell Loss from Bleeding
Sometimes, a low red blood count in dogs can be indicative of some blood loss happening somewhere in the dog’s body. The blood loss doesn’t have to be evident. Many times, the blood loss is happening internally and the dog owner may have no clue of what is going on.
Loss of blood can be happening because of a bleeding ulcer in the stomach. A dog with a bleeding ulcer may vomit blood that looks like coffee grounds or may present with present black, tarry stools due to the digested blood.
Another unfortunate cause of internal blood loss in dogs is what is known as hemangiosarcoma, an aggressive cancer affecting the dog’s heart or spleen. When the cancer affects the spleen, there may be bleeding into the belly when it ruptures. Affected dogs may have pale gums, onset of lethargy and weakness and a painful abdomen. Affected dogs with spleen masses or cancer should see the vet immediately.
Another cause of significant blood loss involves ingestion of rat poison which interferes with the blood’s ability to clot causing internal bleeding. If your dog recently ate rat poison, consult with your vet immediately!
Body Destroying Red Blood Cells
Sometimes, the dog’s body may be destroying red blood cells. As destructive as this sounds, it’s not very uncommon and it’s triggered by the immune system which believes that red blood cells are foreign invaders that must be destroyed.
In this case, the immune system destroys the red blood cells as they’re being produced in the bone marrow. A common culprit for this is Immune Mediated Hemolytic Anemia (IMHA). Obviously, this is a serious condition, that requires prompt treatment!
Usually, such auto-immune disorders are treated with steroids that suppress the immune system such as prednisone, cyclosporine, and azathioprine. In some cases, when these traditional forms of therapy are not working, for those who can afford it, a transfusion with human immunoglobulin may help. According to Resident Vet, in dogs offered with this option, there is often dramatic improvement in 24 hours.
If your vet has found a low red blood cell count, further testing is often required. The vet may ask whether the dog has eaten any toxins such as rat poison, garlic or onions (Heinz anemia), zinc (in pennies minted after 1982, human ointment and sun tan lotion) or high doses of aspirin or Tylenol.
The vet may also test for tick-borne diseases, heartworm disease and may run blood tests to check for kidney and liver function. The vet may check for signs of chronic infections.
If an autoimmune disorder is suspected, a Coomb s test may be suggested so to check for the presence of antibodies against red blood cells.
Generally, the levels of protein in the blood can give some insight as to whether the dog is suffering from blood loss. When protein levels are low along with low red blood cell count, this is often suggestive of blood loss. If protein levels are normal or high, then there are chances that somehow red blood cells are being destroyed or the bone marrow is not producing enough.
A blood test checking for reticulocytes, can help determine whether the bone marrow is making more red blood cells to compensate for a low count (regeneration).
If there are no signs of regeneration, then a bone marrow biopsy may be done. A bone marrow biopsy can help determine the presence of malignant cells and also help determine whether the bone marrow is attempting to produce new red blood cells.
“There are many things that can cause a low red cell count such as internal bleeding, intestinal parasites such as hookworm, a spleen tumor, bone marrow cancer, immune mediated hemolytic anemia and many more.” Dr. Marie
As seen, lowered red blood cells in dogs is a problem that should not be taken lightly! Sure, some cases of anemia are mild and might not be so urgent, but the underlying causes at times can be quite serious, so best to play it safe. And for those wondering, feeding the dog liver or other iron-rich foods, are unlikely to help in many cases because dogs do not need additional iron in their diets the same way people do and most likely the anemia is due to an underlying cause that needs immediate attention!
“In dogs, lack of iron in the diet is virtually unheard of as a reason for anemia (quite different from humans) as dog foods have plenty of iron in them.” Dr. Fiona