Page 1076 - The Veterinary Care of the Horse
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NEUTROPHILS
Neutrophil numbers rise in response to acute or chronic inflammation which may be caused
VetBooks.ir by bacterial, viral or parasitic infection. They are able to migrate from the small blood vessels
into connective tissue where they engulf and kill bacteria. In severe, overwhelming bacterial
infections and acute viral infections, their numbers in the circulation may be low.
LYMPHOCYTES
These cells are important for recognizing antigens such as viruses, bacteria and fungi. They
stimulate antibody production. Their numbers may decrease in response to a viral infection.
EOSINOPHILS
Eosinophils may rise in response to allergic or inflammatory conditions. They play a role in
protecting the horse against parasitic infections but increased numbers are found in the
tissues close to the parasite rather than the circulation. Their numbers are lowered by
administration of corticosteroids or in horses with PPID (Cushing’s disease).
MONOCYTES
The numbers increase in the presence of inflammation from tissue damage or infection. They
migrate from the blood into the tissues and become transformed into large macrophages
which engulf and digest bacteria, viruses and dead tissue.
BASOPHILS
The numbers of basophils in equine blood are very small. They are involved in allergic and
parasitic conditions.
Biochemistry
Biochemical tests are carried out on serum or plasma. Plasma is the fluid part of whole blood
and it contains fibrinogen. Serum is the liquid component of clotted blood. It does not
contain fibrinogen as this has been used up in the clotting process. These tests provide a great
deal of information about what is happening in different parts of the horse’s body. Variations
from the normal range can point to problems in specific organs, and so they can be a valuable
aid to diagnosis. They also play a part in the routine monitoring of performance horses and
may be helpful in making training and management decisions. The following biochemical
tests can be performed.
