1040638714546490

546490
research-article2014
VDIXXX10.1177/1040638714546490Hematology as a diagnostic tool in bovine medicineRoland et al.
Review
Journal of Veterinary Diagnostic Investigation
2014, Vol. 26(5) 592­–598
© 2014 The Author(s)
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DOI: 10.1177/1040638714546490
jvdi.sagepub.com
Hematology as a diagnostic tool in
bovine medicine
Leonie Roland, Marc Drillich, Michael Iwersen1
Abstract. The objective of the current review is to provide the reader with an overview of the bovine hematological
profile. Sample collection, bovine reference ranges, and cattle-specific characteristics of erythrocyte, leukocyte, and platelet
parameters are reviewed. Furthermore, diseases associated with abnormalities in the complete blood cell count of cattle are
discussed.
Key words: Blood; cattle; complete blood cell count; hematology; hemogram.
Introduction
Hematologic analysis is not only relevant for diagnosing disorders of the hematologic system but also helpful in the diagnosis of many organ and systemic diseases. Although the
diagnosis of a disease can only occasionally be based solely
on a complete blood cell (CBC) count, the hemogram may
contribute valuable information in the diagnosis, surveillance, and formulation of a prognosis regarding the future
progression of a disease in an individual. The objective of the
current review is to provide bovine clinicians and laboratory
technicians with an overview of the sample collection process, bovine reference ranges, cattle-specific properties of
blood cells, and diseases associated with abnormalities in the
hematological profile of cattle. Because automated cell
counters have become more and more popular in veterinary
practice, the focus of the present review is on abnormalities
detectable by automated cell counters (i.e., abnormalities in
the number, volume, and hemoglobin concentration of blood
cells rather than on abnormal morphology). However, if
pathological or irregular results are discovered, or abnormal
morphology or blood cell function impairment is suspected,
an additional microscopic blood smear evaluation is strongly
recommended.
Blood sampling and storage
The most accessible and commonly used vessels for blood
collection in cattle are the external jugular vein and the coccygeal vessels. If possible, animals should be calm to avoid
stress-related changes of the hemogram.22,39 For hematologic
analysis, samples must be collected in tubes coated with anticoagulant agents, preferably potassium–ethylenediamine
tetra-acetic acid (EDTA/K3) with a concentration of 1.27 mg
EDTA/K3 per ml of blood, or disodium–ethylenediamine
tetra-acetic acid (EDTA/Na2) with a concentration of 1.5 mg
EDTA/Na2 per ml of blood. Heparin is not recommended for
general hematological use in cattle because it results in deviations of leukocyte counts.13 Mixing should occur by carefully
inverting the tube several times. The correct blood quantity
should be collected in the sample tube, because an inappropriate ratio of sample blood to anticoagulant might cause erroneous results for red blood cell (RBC) parameters and indices.
Samples can be stored up to 24 hr at 4°C. Platelet counts
should be conducted within 4 hr after venipuncture.22,39,47
Bovine hematological reference ranges
The most appropriate reference range is generated from a
group of healthy animals with environmental and physiological characteristics as similar to the patient as possible. As in
all species, a certain amount of physiological variability is
observed in hematologic profiles of cattle. Variables that
contribute to the thresholds and width of reference intervals
include age, sex, stress, diet, body condition, reproductive
status, recent activity, hydration, ambient temperature, and
altitude.28,50 Reference intervals for bovine hematologic
parameters from 3 sources are summarized in Table 1.
Many commonly used hematology reference intervals
originate from research undertaken in the 1960s. A 2010
study16 compared reference intervals of healthy North American cows from 1957 to 2006 to account for changes in the
From the Clinical Unit for Herd Health Management in Ruminants,
University Clinic for Ruminants, Department for Farm Animals and
Veterinary Public Health, University of Veterinary Medicine Vienna,
Vienna, Austria.
1
Corresponding Author: Michael Iwersen, Clinical Unit for Herd
Health Management in Ruminants, University Clinic for Ruminants,
Department for Farm Animals and Veterinary Public Health, University
of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
[email protected]
Hematology as a diagnostic tool in bovine medicine
593
Table 1. Bovine hematology reference intervals according to 3 sources.*
Parameter
Erythrocytes
Hematocrit
Hemoglobin
Mean corpuscular volume
Mean corpuscular hemoglobin
Mean corpuscular hemoglobin concentration
Red cell distribution width
Reticulocytes
Leukocytes
Segmented neutrophils
Band neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Platelets
Mean platelet volume
Unit
Wood and Quiroz-Rocha
(2010)50†
Kraft and Dürr
(2005)27‡
George et al.
(2010)16§
106/μl
%
g/dl
fl
pg
g/dl
%
103/μl
103/μl
103/μl
103/μl
103/μl
103/μl
103/μl
103/μl
103/μl
fl
4.9–7.5
21–30
8.4–12.0
36–50
14–19
38–43
16–20
0
5.1–13.3
1.7–6.0
0–0.2
1.8–8.1
0.1–0.7
0.1–1.2
0–0.2
160–650
4.6–7.4
5–10
28–38
9–14
46–65
11–17
31–34
NA
NA
5–10
1.0–3.5
0.0–0.2
2.5–5.5
0–0.3
0.3–1.5
0–0.1
300–800
NA
5.1–7.6
22–33
8.5–12.2
38–50
14–18
36–39
15.5–19.7
NA
4.9–12.0
1.8–6.3
Rare
1.6–5.6
0–0.8
0–0.9
0–0.3
193–637
4.5–7.5
* NA = not available
† Reference intervals for the ADVIA 120 hematology analyzer from 99 clinically healthy cows, 50% in first lactation, all milking for 30–150 days, from 10
farms in Ontario, Canada.
‡ Mainly based on several German original research papers.
§ Reference intervals for the ADVIA 120 hematology analyzer from 58 healthy adult dairy Holstein cows in mid-lactation (at least 18 weeks into lactation)
and producing 50–70 pounds of milk per day from 4 herds in California.
CBC count during the past 50 years. The main findings
included a significant increase in reference ranges for neutrophil counts over the study period, whereas reference intervals for lymphocyte, monocyte, and eosinophil counts as
well as hemoglobin concentration had decreased. Genetic
selection and decreased prevalence of bovine virus diarrhea
were suggested as possible reasons for higher neutrophil
counts.16 Animals persistently infected with Bovine viral
diarrhea virus (BVDV) exhibit significant neutropenia,35
thus the absence of persistently infected animals in the study
might have contributed to increased neutrophil numbers. The
reduced eosinophil count was assumed to be caused by
decreased exposure to parasites due to modern husbandry
and parasite control programs. The authors recommended
that laboratories should establish their own reference ranges
to reflect current cattle populations.16
Red blood cell parameters and
their interpretation
Erythrocytes have an average diameter of 5–6 μm in cattle,
which is small compared to other species. The key function
of erythrocytes is the transport of oxygen, which is bound to
hemoglobin. Erythropoiesis, which takes approximately 5
days, is stimulated by erythropoietin and occurs in the bone
marrow parenchyma. Bovine erythrocytes have a relatively
long life span of 130–160 days.7,50
An RBC count typically includes the total number of
RBCs, hematocrit (HCT), hemoglobin (HGB), erythrocyte
indices, and occasionally the red cell distribution width
(RDW). Erythrocyte indices include mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and
mean corpuscular hemoglobin concentration (MCHC).7
In general, beef cattle breeds have higher RBC counts than
dairy cattle, bulls have greater RBC counts than cows, and
nonlactating cows have higher RBC counts than lactating
cows.50 In calves, HGB, MCH, and MCHC decrease during
the first month and then start to increase during the first 3
months of life.31 In young calves, RBC counts might be
higher, and MCV and MCHC might be lower than in adults.9,22
Common indications for RBC analysis are clinical anemia or hemorrhage. In absolute anemia, RBCs, HGB, and/or
HCT are decreased. Relative anemia is caused by an increase
of plasma volume (e.g., during pregnancy or after fluid therapy). Anemia can be categorized into regenerative and nonregenerative anemia according to the bone marrow response,
and can also be classified with regard to the cell size (normocytic, macrocytic, and microcytic, indicating normal,
increased, and decreased MCV, respectively) and hemoglobin concentration (normochromic, hypochromic, and hyperchromic, indicating normal, decreased, and increased HGB,
respectively).7,27
Causes for regenerative anemia are hemorrhage or hemolysis. With acute blood loss, the RBC parameters are initially
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Roland et al.
within the reference ranges because cells and plasma are lost
in the same proportion. Diminished RBC count and HGB
can be found only after several hours, when fluid in the blood
vessels is replaced and dilutes the blood. In cattle, regeneration of erythrocytes begins after approximately 2 days, and
takes weeks to be fully accomplished. In chronic hemorrhage, RBC count, HCT, and HGB are decreased while reticulocytes as well as MCV are increased. In ruminants, only a
moderate rise in reticulocytes is observed in responding anemia. If regenerative capacity is depleted, chronic bleeding
anemia can become nonregenerative.7 Causes for hemorrhage include trauma, abomasal ulcers, hemorrhagic enteritis, vena cava syndrome, blood-sucking parasites (e.g.,
Haemonchus spp., lice, or ticks), hemostasis defects, and
vessel erosion or rupture. Hemolytic anemia is caused
by blood parasites, toxins, electrolyte imbalances, hypoosmolality,7,19,22 or autoimmune reactions.40 In cattle, common
causes for hemolysis include unsuitable food and toxic
plants, such as cabbage (Brassica spp.), onions (Allium
cepa), rye grass (Lolium spp.), or red maple (Acer
rubrum).2,7,19,21,50 Microorganisms infecting ruminant RBCs
include rickettsia (Anaplasma marginale),1,20,26 protozoa
(Babesia spp., Theileria spp., Trypanosoma spp., and Sarcocystis spp.),1,7,20,22,34,53 or bacteria (Mycoplasma wenyonii,
Leptospira spp., and Clostridium spp.).1,22,37 Further factors
are copper deficiency or chronic copper intoxication,22,30,50
hypophosphatemia (postparturient hemoglobinuria),7,19,29
and water intoxication.19,27,41
Nonregenerative anemia generally occurs in the following combinations: normochromic and normocytic, normochromic and macrocytic, or hypochromic and microcytic.7,27
Normochromic, normocytic anemia is seen in nonspecific
disease, especially during chronic inflammation. It is also
observed in connection with erythropoietin deficiency due to
chronic renal disease or endocrine disorders, as well as bone
marrow depression, certain drugs (e.g., estrogen, chloramphenicol, or cytotoxic cancer medication), toxins (e.g., lead
poisoning), abscesses, and neoplasia.7,15,22 Normochromic,
macrocytic anemia occurs with deficiencies in vitamin B12,
folic acid, or cobalt.7,19 It is also found in polled Hereford
dyserythropoietic anemia, a congenital anemia accompanied
by dyskeratosis and progressive alopecia.49 Hypochromic,
microcytic anemia is commonly caused by iron deficiency as
observed during chronic hemorrhage or in calves raised
solely on milk,19,22 but microcytes are also observed in copper deficiency, pyridoxine deficiency, or lead toxicosis.7
The term polycythemia is used to describe increased RBC,
HCT, and/or HGB. Relative and absolute polycythemia are
differentiated. Relative polycythemia is triggered by a reduction in plasma volume in dehydrated individuals or by splenic
contraction. Absolute polycythemia is caused by an increased
number of erythrocytes. Primary polycythemia or polycythemia vera is a myeloproliferative disorder resulting from
autonomous stem cell proliferation. Secondary polycythemia
is triggered by increased erythropoietin production. It occurs
under hypoxic conditions, which can be of physiological
(e.g., high altitude) or pathological (e.g., pulmonary or cardiac disorders) origin. It is also observed with renal tumors
and cysts.7,22,27 A bovine hereditary polycythemia is known
in Jersey and Hereford cattle.19
The RDW is the coefficient of variation of the RBC volume distribution and is a measure of anisocytosis.7 The RDW
can be presented as a diagram with the cell volume on the
x-axis and the number of cells on the y-axis. The presence of
macrocytosis or microcytosis results in abnormal peaks and
a wider distribution. In healthy calves, MCV is decreased,
resulting in a wider RDW. Further examples of conditions
associated with an increased RDW include iron deficiency,
or other trace mineral deficiencies associated with macrocytic or microcytic anemia.4,9,24,27
The small size of ruminant erythrocytes might cause
falsely low results for RBC counts if automated analyzers are
not calibrated correctly for cattle. Erroneous results for RBC
parameters and indices might also occur due to in vitro
hemolysis or inadequate blood sample–to–anticoagulant
ratio, which might cause erythrocyte shrinkage or dilution.22
White blood cell parameters and
their interpretation
White blood cells (WBCs) or leukocytes play an essential
role in immune defense, and include different subpopulations: neutrophil, eosinophil, and basophil granulocytes,
monocytes, and lymphocytes. Leukocytes are produced and
mature in the bone marrow, and, in the case of lymphocytes,
in the lymphoid tissues. The number of leukocytes in the
blood constitutes only a small percentage of the total population and undergoes wide fluctuation. In the vasculature, a
marginal pool and a circulatory pool of neutrophils are differentiated. The marginal neutrophils are attached to the
endothelial cells, but detach and join the circulatory pool if
blood pressure rises and the blood flow velocity increases.
Therefore, every change in blood pressure can result in a
change in the amount of leukocytes present in the blood.27,48
A complete WBC count is composed of the total number
of leukocytes, the relative differential blood count, and the
absolute differential blood count. Usually, the different subpopulations, as well as band and segmented neutrophils can
be distinguished.27,50
In cattle, the total number of WBCs decreases with age.19
Lymphocytes are the dominant subpopulation, but the lymphocyte proportion varies with age. The newborn calf has
more granulocytes than lymphocytes.22,50 During the first
month of life, calves exhibit a decrease in the overall number
of WBCs, neutrophils, and lymphocytes, followed by an
increase thereafter.31 Within approximately 3 months, the
lymphocyte percentage increases up to 80% of the total circulating WBC population. In the adult, the lymphocyte concentration decreases progressively but remains the dominant
cell type. The neutrophil-to-lymphocyte ratio in adult cattle
Hematology as a diagnostic tool in bovine medicine
is approximately 1:2, which is low compared to other domestic animals.22,46,50 Eosinophils are below adult reference
ranges after birth and increase with age.9,27,50
Compared with other species, cattle have a small bone
marrow reserve for granulocytes. This results initially in a
neutropenic rather than a neutrophilic reaction in an early
inflammatory process. Neutrophilia and a left shift might be
observed only after the speed of granulopoiesis is increased.
After 3–5 days, immature and mature neutrophils might
rebound.19,22,46,50 Cattle neutrophil counts rarely exceed
30,000 cells/μl.46,48 Neutrophil numbers decrease in the postpartum period,18 and lactating cows have lower WBC counts
than nonlactating cows.50
Indications for a leukogram include diagnostics, general
health assessments, monitoring of a disease, or monitoring of
therapeutic actions. However, it is seldom possible to come to
a definite diagnosis based solely on a WBC count.27 Sequential leukograms can help establish a prognosis. The return of
the leukogram within normal limits together with clinical
improvement can be interpreted as a favorable sign, whereas
a rapid fall in leukocytes without clinical improvement is
regarded as a grave prognostic sign. Guarded or poor prognoses should be formulated with persisting neutropenia, a
degenerative left shift, or severe persistent leukocytosis.19,22,48
The mechanisms underlying leukocytosis include
increased release from the bone marrow, decreased emigration into the tissues, and a shift of cells from the marginal into
the circulatory pool.48 Physiologic leukocytosis is seen in
association with stress, excitation, fear, exercise, or parturition. A stress leukogram is characterized by neutrophilia,
lymphocytopenia, eosinopenia, and occasionally monocytosis. It is triggered by endogenous or exogenous corticosteroid
exposure.22,25,27,46 A short-term physiological leukocytosis is
also observed after epinephrine release.22,46 Causes for pathological leukocytosis include infectious diseases, endogenous
or exogenous intoxication, endocrine conditions, central nervous disorders, anaphylactic shock, leukemia, and bovine
leukocyte adhesion deficiency (BLAD).27
Leukopenia is caused by decreased production, increased
tissue demand, and consumption combined with marginalization. In general, it is observed in connection with viral
infections, circulatory shock, peracute inflammation, cytotoxic substances, as well as hematopoietic stem cell disorders and bone marrow atrophy.27 In cattle, leukopenia often
occurs with metabolic disorders, liver disease, and infectious
diseases (e.g., mucosal disease, paratuberculosis, or salmonellosis). Panleukopenia, a depression of all WBC subpopulations, is observed in viral disease (e.g., mucosal disease,
infectious bovine rhinotracheitis), rickettsiosis, bacterial
septicemia, and purulent splenitis.19
The most common causes for neutrophilia are chronic
inflammation and stress. Chronic inflammation has been
reported among other infections of the udder, urogenital
tract, gastrointestinal tract, liver, respiratory tract, heart, and
central nervous system. In bovines, neutrophilia is also com-
595
monly observed with acute purulent processes, such as endometritis or metritis, retained placenta, acute bacterial mastitis,
and foreign body peritonitis.19,46 Inflammatory neutrophilia
is seen in viral, bacterial, protozoal, parasitic, and fungal
infections.46,48 Additionally, neutrophilia is observed with
noninfective inflammation (traumatic injuries, necrosis,
infarction, burns, thrombosis, etc.), neoplasia, intoxication,
endocrine disorders, hemorrhage, and hemolysis.27,48 In cattle, stress-induced neutrophilia is also associated with
abomasal displacement, ketosis, indigestion, and dystocia.48,51,52 Severe leukocytosis, exceeding 40,000 cells/μl and
sometimes even 100,000 cells/μl, based on a marked increase
in neutrophils may be a sign of BLAD in Holstein Friesians.
BLAD is usually diagnosed in calves, and most affected
calves die within 1 year of age.17,32,33,48
Neutropenia occurs in ruminants during the first 1 or 2
days of severe, acute inflammation, including sepsis, mastitis, peritonitis, metritis, enteritis, and pneumonia. It can be
caused by viral (BVDV, Bluetongue virus, Border disease
virus),46 rickettsial (Anaplasma phagocytophilum,43,46
Ehrlichia ruminantium), protozoal (Theileria sp.),34,46 and
fungal infections, as well as bone marrow disease, toxins,
neoplasia, or idiosyncratic drug reactions.27,48
Conditions commonly associated with eosinophilia
include type I (immediate)23,45 hypersensitivity reactions and
parasitic infection.22,27,46 Additional causes are neoplasia,
infections, and drug reactions.48 Eosinopenia might also
occur in the early phase of infectious diseases, uremia, and
acute hemolysis.27 Extreme eosinopenia has been associated
with Theileria infections.34,46
Basophilia has been linked to hyperlipidemia and occasionally to allergies, ulcerations,27 and parasitic infections (ticks).8,46
Basopenia is not commonly reported in the literature because
basophil reference intervals often include zero.46,48
Lymphocytosis can occur in the healing phase of infectious diseases, during chronic antigenic stimulation due to
infectious agents, neoplasia, and hypoadrenocorticism.27,48
Reactive lymphocytosis is observed during chronic purulent
diseases, such as hepatitis, peritonitis, pericarditis, nephritis,
mastitis, or bronchopneumonia.19 Bovine leukemia virus
(BLV) is the causative agent of enzootic bovine leukosis.
Infection with BLV results in a persistent lymphocytosis
driven by an increase in B cells with abnormal lymphocyte
morphology in up to 30% of affected cattle. Only a small
percentage of animals with lymphocytosis develop bovine
lymphoma. In some cases, WBC counts may exceed 100,000
cells/μl.3,12,22
Reasons for lymphocytopenia include acute stress, viral
or bacterial infection, immune suppression, chronic renal
insufficiency, and application of corticosteroids.22,27 It is
also induced by loss of lymph and disruption of lymph node
architecture (e.g., in paratuberculosis, inflammation, or
neoplasia).48
Monocyte numbers are variable in cattle and are thus not
a sensible indicator for a specific disease.22 Monocytosis has
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Roland et al.
been observed during acute stress and in the healing phase of
acute as well as chronic infections. It is further caused by
hemolysis, hemorrhage, exudative inflammation, necrosis,
ulceration, and corticosteroid therapy.27,48 Monocytosis was
also found to be a successful marker of bacteremia and bacterial endocarditis48 as well as puerperal infections.19 Monocytopenia may be associated with endotoxemia,46 viremia,
and inflammation,22 but has so far not been proven to have
much clinical relevance.48
With automated cell counters, falsely low WBC counts
might occur due to clumping of leukocytes, and falsely high
WBC counts might be caused by nucleated red blood cells,
insufficient lysis of erythrocytes, excessive Heinz bodies, or
clumping of platelets.48
Platelet parameters and
their interpretation
Platelets are anuclear cytoplasmic fragments of megakaryocytes, and play an essential role in hemostasis.6,38 With an
average mean platelet volume (MPV) of 4.0–4.8 femtoliters,
bovine platelets are small compared to those of other species.5 Up to 30–40% of platelets are sequestered in the spleen
and enter circulation in response to epinephrine release.
Thrombocytes are also stored in the liver and bone marrow.6,38 Bovine platelets survive up to 10 days in peripheral
blood.50 In intact blood vessels, platelets circulate predominantly in the marginal pool.27 The total number of platelets is
influenced by the amount of production, consumption,
sequestration, and loss.6,38
Platelet numbers increase significantly during the first 2
weeks of age and more slowly thereafter during the first 3
months. Platelet counts in calves might be within31 or above
adult reference intervals.9 The following parameters can be
estimated: total number of platelets, MPV, thrombocrit or
plateletcrit, and platelet distribution width.6,38
In practice, a count of platelets might be indicated with
severe hemorrhage or increased bleeding tendency. This
includes clinical signs such as petechia, ecchymosis, hematuria, epistaxis, melena, hematemesis, and hyphema.38,44
Thrombocytosis occurs physiologically as a consequence
of epinephrine-induced splenic contraction. Essential or primary thrombocytosis is an uncommon myeloproliferative
condition. Reactive or secondary thrombocytosis is triggered
by cytokine release and is observed in connection with stress,
chronic blood loss, inflammation, neoplasia, or iron deficiency. Enhanced thrombopoiesis is also seen with inherited
megakaryocyte disorders.6,42 An increased platelet count
might be associated with an increased risk for thrombosis.6,27
Thrombocytopenia is found in excessive consumption
(e.g., with blood loss, disseminated intravascular coagulation, or thrombocytopenic thrombotic purpura), decreased
platelet production (e.g., in myelophthisis or bone marrow
hypoplasia linked to toxins), destruction (e.g., due to infections, toxins, drugs, neoplasia, or immune-mediated), or
distribution disorders (e.g., splenomegaly).6,27,38,44 Examples for infectious diseases causing thrombocytopenia
include salmonellosis, leptospirosis, babesiosis, theileriosis,34,44 anaplasmosis,43 and BVDV infection.6,10,36,44 Examples for toxins leading to platelet destruction are bracken
fern (Pteridium aquilinum), mycotoxins (trichothecene),
black fly (Simuliidae spp.) toxin, and coumarin rodenticides.19,44 Thrombocytopenia associated with leukopenia
and bone marrow depletion is observed in bovine neonatal
pancytopenia, a hemorrhagic disease of newborn calves
observed since 2006, which is thought to be linked to an
inactivated vaccine against BVDV in dams.11,14
Enlarged platelets are associated with accelerated production as well as myeloproliferative disorders and hyperthyroidism.38 Decreased MPV or platelet fragments are observed
in iron-deficiency anemia, bone marrow failure, and immunemediated thrombocytopenia.6
Automated cell counters should be calibrated adequately
to account for the small size of bovine platelets. Falsely elevated platelet counts might be flagged if fragmented RBCs
or WBCs are erroneously counted as platelets by an automated analyzer.42 Platelet clumping might be a reason for
indication of thrombocytopenia in automated cell counters.
Platelet clumping can result from exposure to EDTA exceeding 4–6 hr or from use of heparin as an anticoagulant.22,44
Storage of blood in EDTA tubes over 4 hr at room temperature or refrigerated might cause platelet swelling, resulting in
falsely increased MPV. Storage over 24 hr can result in fragmentation of platelets.6,38
Conclusions
Physiological and pathological characteristics of the bovine
hemogram were discussed. The results of a CBC count are
often helpful in the diagnosis, monitoring, and prognosis of
a disease. If automated cell counters are used to obtain a
CBC count, results should be interpreted with care to avoid
false-positive or false-negative outcomes. If in doubt, a
manual microscopic evaluation of the blood sample should
be carried out. In cattle, changes in the CBC count, especially in the leukogram, might not be as pronounced as in
other species even during severe illness. Therefore, a diagnosis or prognosis should not be based on hematologic
results solely, but should also take findings from the clinical
examination or other diagnostic procedures into consideration.19
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect
to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Hematology as a diagnostic tool in bovine medicine
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