Screening for Hidden Diseases Prior to Breeding
Blood and Urine Analysis
Nancy McDonald, RN
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Prior to breeding, the breeder must consider the health and well
being of not only the bitch but also the future get as well. Blood
and urine analysis, two standard, economical tests can be preformed
in advance of a breeding on both the sire and dam, indicating the
health of the sire and dam and the future genetic health of the get.
In the light of today’s economics, breeding a litter of Bichons is
an economic investment. The cost of stud fees and vet fees continue
to increase. Whelping and raising a litter of pups by a bitch whose
health is compromised could jeopardize not only the pups she
produces but also her future breeding potential. A bitch may not
tolerate whelping and lactating if she is unhealthy, and a dog or a
bitch may have decreased fertility if hidden health conditions
exist. Blood and urine analysis can be used to screen breeding pairs
for internal organ function alerting the breeder to a potential
health problem or an inherited genetic disease. Many health
conditions can remain hidden, with no apparent symptoms, until the
dog is stressed or older in age, such as endocrine diseases (Cushings,
Addisons, diabetes, hypothroid), bladder stones, liver or pancreas
disease, kidney disease, cancer, bleeding disorders, anemia and
infections.
A complete blood analysis involves the assessment of cellular
components (solids) and serum (liquids). The solids are red blood
cells, white blood cells, and platelets. Red blood cells (RBC) are
manufactured in the bone marrow. Their function, made possible by
the hemoglobin they contain, carry oxygen from the lungs to every
cell in the body. Anemia, too few RBCs, is caused by failure of bone
marrow to produce adequate numbers of RBCs. Bone marrow failure is a
common complication caused by many chronic disease processes such as
liver dysfunction, cancer, and advanced renal failure.
White blood cells (WBC) fight infections by attacking them directly
and by producing antibodies to neutralize them. WBCs are produced in
the bone marrow except for one, a lymphocyte, produced in the lymph
nodes. During severe infections, such as pyometra or hepatitis, the
number of WBCs in the blood will rise. However, in an overwhelming
infection, as with parvoviral infection, WBCs are used up faster
than they can be produced resulting in an excessively low count.
Platelets, also known as thrombocytes, are produced in the bone
marrow and play a critical roll in blood clotting. Immune-mediated
thrombocytopenia is a disease where the immune system attacks and
destroys platelets, causing their numbers to drop to a dangerously
low level that can cause hemorrhaging.
When the cells, (RBCs, WBCs, and platelets), are removed from the
blood, a fluid remains, called serum. Serum contains electrolytes,
minerals, enzymes, and toxic waste products. The analysis of these
factors is called blood chemistries.
Glucose is one of the factors measured in a blood chemistry test. A
high glucose level can indicate diabetes. Low glucose levels can be
a complicating factor in dogs with severe infections or pancreatic
cancer. Another factor, blood urea nitrogen (BUN) and creatinine,
are waste products of protein metabolism. The kidneys are
responsible for removing them from the bloodstream. In kidney
failure, they both rise. Other enzymes, amylase and lipase, detected
in the blood stream may be indicative of an inflamed pancreas. Liver
enzymes, (known by their acronyms –ALT, AST, ALP, and GGT), rise
with liver inflammation, indicating, among other things, hepatitis,
liver shunt, or Cushing’s disease. In advanced liver disease,
bilirubin, the by-product of the breakdown of red blood cells,
rises. The bilirubin also rises in dogs with immune-mediated
hemolytic anemia.
The primary proteins that are analyzed in blood are albumin and
globulin. Albumin is produced in the liver. Albumin levels fall when
liver function is compromised, or in a malnourished dog, or heavy
parasite load, or inflammatory bowel disease or kidney inflammation.
Globulins are antibodies that fight infections and rise with
long-standing infections and with a certain cancer, myeloma.
The most commonly measured electrolytes and minerals in the blood
are sodium, potassium, calcium, and phosphorus. Lactating bitches
can have low levels of calcium. A high calcium level could indicate
the presence of a malignant cancer. Abnormal sodium and potassium
could indicate Addison’s disease. A rise in phosphorus signals loss
of kidney function. A low thyroid hormone level suggests
hypothyroidism or a range of illnesses that suppress the activity of
the thyroid gland.
The primary role of the kidneys is to clear toxic waste products
from the bloodstream and to help maintain fluid balance. Changes in
the urine can be indicative of changes in the blood. Logically, both
tests, a blood analysis and urinalysis, are performed when
evaluating the health of breeding pairs.
A midstream urine sample (collecting the urine after the dogs starts
the stream) can be collected in a clean container at home. Though
making a “free catch” is easy in a male dog, it can be challenging
in a low-squatting bitch. A soup ladle or a small, flat pie plate
may be needed to collect a sample from a bitch as she squats to
urinate. Also, a veterinarian can catheterize a dog’s urethra or
collect it by cystocentesis, a process by which a needle is inserted
through the belly wall directly into the bladder. The cystocentesis
method is ideal if a sterile sample is going to be sent to the
laboratory for a bacterial culture.
A urinalysis evaluates the physical properties, chemical properties
and microscopic properties of the urine. Physical properties of
urine are the color, appearance, specific gravity and acidity.
Normal color of urine is tinted with yellow. Other color may
indicate blood in the urine or infection. Be aware that food
consumed may change urine color. The appearance of urine should be
clear or slightly hazy. Cloudiness may indicate the presence of
white blood cells, bacteria, crystals or mucus. Specific gravity is
the density of the urine (pure water is 1.000). Normal SG of a dog
contains salts that raise the SG to over 1.030. In kidneys unable to
concentrate urine and hormone imbalances such as Cushings, the
specific gravity is less than 1.012. The pH, balance between acidic
and alkaline properties, of a dog is between 6 and 7. Bacteria in
the bladder or kidneys often cause the pH to rise above 7.
Chemical properties (using a dipstick) can indicate a higher amount
of protein than the normal trace amount. Levels rise with infection
and fever. Glucose can indicate diabetes. Ketones, too, are seen in
diabetes and malnutrition. A small amount of bilirubin, the
byproduct of the breakdown of red blood cells by the liver, is
normal, but if the level is high, the liver function needs to be
checked. Blood in the urine, in most cases, is due to bleeding in
the urinary tract and often indicates bladder stones. Other
hemoglobin in the urine could result from hemolytic anemia or a
urinary tract tumor.
Once urine is centrifuged, the fluid portion is discarded and the
material that sinks to the bottom of the tube is analyzed under a
microscope and is termed cytology. Red cells confirm the presence of
blood. Red and white cells in urine sediment indicate an
inflammation in the urinary tract. The presence of bacteria in the
urine suggests infection. However, unless the urine was collected by
cystocentesis, it may be a contaminant. Crystals in the sediment
commonly form when the urine pH rises (when bacteria are multiplying
in the urine). Crystals may also suggest the presence of stones in
the bladder.
Because an abnormal blood test or urinalysis may be indicative of
problems needing further exploration, getting them well in advance
of breeding is advised. These standard tests performed in the vet’s
office could well benefit the next generation of Bichons.
References:
- Laboratory Tests: Implications for Nurses by Dr. Mikel A. Rothenberg, 1998.
- “Blood Tests May be the Window to Your Dog’s Health” by Jeff Grognet DVM, AKC Gazette, November 2004.
- “Urine Interpretation: What Do Those Test Results Really Tell You and Your Vet?” by Jeff Grognet DVM, AKC
Gazette, October 2004
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