BLOOD AND BLOOD PROFILES
by Tom Meulman (Australia)
Everything that happens in or to the body affects the composition of the blood, simply because the blood supplies every part of the body with nutrients and oxygen, removes wastes, breakdown components and carbon monoxide.
On the other hand, everything that affects the blood will affect the body in some way.
It is for this reason that blood profiles are one of the best tools available to the trainer in determining the true state of the greyhound's health.
However, there are a large number of tests that may be carried out on a blood sample, and it is mainly the cost of these tests, that limits the number of compounds that are tested for at any one time.
It is therefore important that the trainer provides the Veterinarian with the right information regarding any symptoms they may have observed in the greyhound. This will assist in determining exactly what compounds of the blood should be investigated.
As with any investigation, if the wrong questions are asked the wrong answers will result.
A good understanding by the trainer as to the functions of the major blood components will greatly improve the overall process.
This knowledge will also assist the trainer in determining whether or not the feeding and training program is affecting the greyhound’s blood profile in any way, thereby the body and ultimately the greyhound’s performance on the race track.
BLOOD
Blood is a liquid that circulates in what is virtually a closed system of blood vessels.
It consists of solid elements; these are the red and white blood cells and the platelets.
All suspended in a liquid medium, the plasma, this also contains solids in the form of proteins; these are Fibrinogen, Albumin and Globulin.
Fibrinogen is one of the main compounds that cause blood clotting.
Blood also contain a number of biological minerals essential for normal muscle function and fluid balance such as Sodium, Potassium, Calcium, Bicarbonate and Phosphorus, as well as the waste products and enzymes produced by the various organs and muscles.
FUNCTIONS OF THE BLOOD
RESPIRATION Transport of oxygen from the lungs to the various tissues and the removal of carbon monoxide from the tissues to the lungs
NUTRITION Transport of absorbed food nutrients
EXCRETION Transport of wastes to the kidneys, lungs and intestines for removal
MAINTENANCE of normal Ph balance within the body
REGULATION of water balance between intracellular and extra cellular fluid
REGULATION of body temperature by the distribution of body heat
DEFENCE against infection with the white cells and circulation of antibodies (anti viral)
TRANSPORT of hormones to regulate the metabolism
TRANSPORT of enzymes and vitamins
HAEMOGLOBIN
This is the oxygen-carrying component of the red blood cells.
Any reduction in functional Haemoglobin will immediately affect performance.
A packed cell volume test (PCV) of the blood will provide some indication of the level of red blood cells and therefore an indication of Haemoglobin levels, however even moderate dehydration will affect the PCV and may provide a misleading result.
Non functioning haemoglobin
The ability of Haemoglobin to carry oxygen to the tissues, may also be affected by the production of non-functioning Haemoglobin taking the place of normal Haemoglobin in the red blood cells, these are Methemoglobin and Sulfhemoglobin.
This alteration to the Haemoglobin may be caused by treatment with anti-biotic Sulphonamides such as Sulphanilamide, Sulphathiazole and Sulphapyrine, or the feeding of raw onions in the diet, due to a component of onion oil called Alylpropyl Disulfide.
It is of some concern that many racing greyhounds are fed meat obtained from diseased or dead cattle that may have been treated with Sulphonamides, or some similar substance and thereby impregnating the meat with a sufficient quantity of drug to cause non-functioning Haemoglobin to be formed.
Of greater concern is the fact that often this meat is treated with a preservative.
The product used is either Sodium Sulphite or Sodium Metabisulphite; both destroy the Thiamine (Vitamin B1) in the diet.
In the long term this may cause severe nervous system damage and possibly even death.
Sodium Metabisulphite, under the right conditions, will breakdown to Sulphur Dioxide.
This is a gas that at 500 parts per million will kill, and it is my opinion that there is a real good chance that both these products may cause problems with the Haemoglobin in susceptible Greyhounds.
Normal blood should contain 19 to 21 g/dl of Haemoglobin. As little as 0.5 g/dl of Sulfhemoglobin or 1.5 g/dl of Methemoglobin is sufficient to cause rapid oxygen depletion of the body during exercise.
It is reasonable to assume that when a greyhound races over its normal distance while suffering this syndrome, all other aspects of the blood profile would show symptoms relating to severe stress.
Further investigation of the Haemoglobin may be of some value in greyhounds suffering sudden loss of stamina when the rest of the blood profile appears normal.
ANAEMIA
This is lower than normal levels of red blood cells, and may result from a decreased production, an increased loss, or an increased destruction of red blood cells.
Decreased production may occur due to loss of function of the blood forming tissue, as with some types of cancers or chronic infections.
Anaemia may also be caused by a lack of iron, B12, and or protein in the diet.
Increased loss may be due to a severe worm infestation or internal haemorrhage and blood loss via the intestines or urine.
While increased destruction is generally caused by a combination of several factors, such as: Infections, excessive workload or stress, increased levels of waste products in the blood or may even be due to regular exposure to Carbon Monoxide from car exhaust fumes entering dog a trailer, simply because Carbon Monoxide combines with Haemoglobin more readily than Oxygen with Haemoglobin.
MCV = Mean Corpuscular Volume
MCH = Mean Corpuscular Haemoglobin
MCHC =Mean corpuscular Haemoglobin Concentration.
The results of tests for MCV, MCH and MCHC are generally used to determine the type and severity of the anaemia.
WHITE BLOOD CELLS (WBC)
A decrease in total white blood cell count is generally associated with severe destruction, an excessive demand, or decreased production by bone marrow and lymphoid cells.
Greyhounds with a chronic low white blood cell count are immune deficient, and often develop secondary bacterial infections.
Low white blood cell counts may also be caused by toxin producing infections.
Bactericidal antibiotics, rather than bacteriostatic antibiotics should be used when there is an infection present, as well as a low white blood cell count.
Chronic inflammation or infection may cause an increase in the white blood cell count.
However, white cell numbers may also increase significantly without the stimulation of inflammation or infection, it may also be due to Epinephrine release from excitement, and is often seen in easily excitable greyhounds and those suffering from the pre-race stress syndrome.
NEUTROPHILS
Because neutrophils comprise a majority of the white blood cells, low neutrophil level is usually associated with a general decrease in all white blood cells.
Low neutrophil level (neutropenia) may be caused by increased use, or decreased production. While severe inflammation, overwhelming bacterial infection or acute viral infection generally causes increased use.
Decreased production is often associated with immune deficiency due to depressed bone marrow and lymphoid cell production. However inappropriate drug administration, as well as Infectious Canine Parvovirus may also cause a low neutrophil level.
Increased neutrophil level (neutrophilia) is usually caused by bacterial infections, but neutrophilia alone does not confirm the existence of an infection.
This is because other non-infectious problems, such as acute pancreatitis, severe stress, Glucocorticoid (Cortisone) therapy, or an increased workload and increased muscular activity may increase neutrophil levels.
Defects in neutrophil function may also increase neutrophil counts, because the existing neutrophils are not effective and more are produced in response to body requirements.
LYMPHOCYTES
Decreased lymphocyte count (lymphopenia) may be caused by chronic infections, severe stress (Hyperadrenocorticism), kidney failure or prolonged use of Glucocorticoid (Cortisone) injections.
As a general rule, low lymphocyte count indicates a viral infection, while prolonged lymphopenia could indicate that the body is unable to respond to the disease.
However, of the total number of body lymphocytes only 10% are in circulation, therefore it is not always possible to be certain in the short term, that low lymphocyte count (lymphopenia) indicates a poor immune response.
Increased lymphocyte count (lymphocytosis) is a common feature of chronic inflammatory disease, and could indicate a severe problem such as leukaemia or cancer.
MONOCYTES
Increases in monocyte count (monocytosis) may be seen in greyhounds suffering severe stress, chronic infection of the stomach or an abscess.
Monocyte numbers also increase in cases of neutrophil defects when monocytes are required to take over some neutrophil functions.
PLATELETS (THROMBOCYTES)
Platelets are produced by the bone marrow and any process that interferes with marrow production will reduce platelet levels, while increased platelet destruction as a result of the body's immune response to infection, also reduces platelet count.
Because the spleen is the main platelet storage site, increased platelet count may occur due to spleen contraction in response to excitement, chronic iron deficiencies, bone fractures or muscle trauma.
EOSINOPHILS
Increase in eosinophils is usually the result of severe skin infection, chronic fungal infection or severe flea, roundworm, hookworm or heartworm infestation.
However, similar symptoms may also be caused by an allergic reaction to wheat in the diet.
Circulating eosinophil level will rapidly decrease after an injection of cortisone or ACTH.
BASOPHILS
Any infection or infestation that results in an increase in eosinophils will generally also result in an increase in circulating basophils in addition, any increase in lipids in blood will also cause an increase in basophils.
LIPIDS
An increase in the amount of circulating lipids in the blood, can be the result of a number of diseases associated with poor fat and carbohydrate metabolism, including: low thyroid function, over active adrenal gland, and pancreatitis.
GLOBULIN
Most globulin (gamma globulin) is synthesized in plasma cells and lymphocytes as a part of the Immunoglobulins.
The major function of this globulin is to act as antibodies in the immune response and to bind certain compounds in the body, such as hormones, and aid in their transport through the blood stream to their sites of action.
Approximately 3% of globulin is manufactured in the liver, these globulin are Metal Binding Globulin, and function to transport iron in the plasma.
When the diet is lacking in iron, this type of globulin increases in number.
However some types of chronic infections or liver disease may cause a reduction of the metal binding globulin, and as result there is a reduction in the ability of the red blood cells to regenerate and anaemia.
The manufacture of functional globulin largely depends on the quality of the dietary protein; the best protein to produce globulin is milk protein, then egg, and then beef muscle protein.
Low Globulin (Hypoglobulinemia)
Causes of decreased globulin are due to decreased globulin production or increased globulin loss.
Decreased production may be due to inadequate diet or decreased liver function.
Increased globulin loss may occur with kidney damage, depressed immune system, or immune system overload by toxin producing bacterial infections.
Low globulin level will make the animal more susceptible to infections.
High Globulin (Hyperglobulinemia)
High globulin count generally results from dehydration or increased globulin production; however, increased production is usually the result of chronic inflammatory conditions, both infectious and non-infectious.
Long-term excessive exercise, with increasing muscle breakdown and inflammation, as well as some types of cancer may also increase globulin production.
There is no doubt, that both human and animal athletes are more susceptible to infections, both viral and bacterial. This appears to come about because of hard exercise, increased muscle destruction and general inflammation, changing the structure of the globulin and reducing its ability to provide the antibodies required for fighting off infections.
There are a variety of disorders that may be associated with increased globulin levels, the cause should be determined and treated appropriately, and if dehydration is present intravenous fluid therapy may be necessary.
ALBUMIN
Albumin is synthesized in the liver from dietary amino acids.
Small amounts of albumin are lost in the urine and faeces, but most albumins are used in various metabolic processes such as tissue healing and repair.
The primary function of Blood Serum Albumin is to maintain the correct pressure of plasma and act as a carrier for various compounds such as bilirubin, calcium, drugs, hormones, toxins and others.
Low Blood Serum Albumin (Hypoalbuminemia)
Hypoalbuminemia may be caused by a large variety of clinical disorders; therefore the physical examination findings are variable.
Symptoms are generally related to the various metabolic processes involving albumin, such as poor tissue repair, soggy muscle tone, and in severe cases, signs of oedema when contributing factors are present, such as blood vessel damage or increased Serum Sodium with water retention.
When assessing the causes of the low serum albumin level, it is helpful to also consider the Serum Globulin level, because serum globulin is usually determined by measuring the total Serum Protein level, and subtracting the albumin concentration.
Globulin levels may provide some clues as to the causes of the low albumin level.
Even though, albumin and globulin levels should be interpreted independently, the Albumin/Globulin ratio may provide a useful indicator of liver function.
Increased Blood Serum Albumin (Hyperalbuminemia)
The only recognized cause of hyperalbuminemia is dehydration, and should be corrected with appropriate fluid therapy.