Comparison of bovine hematology reference intervals from 1957 to 2006

Lymphatic fluid for the detection of Mycobacterium avium subsp. paratuberculosis in cows by PCR, compared to fecal sampling and detection of antibodies in blood and milk

Johne's disease (JD), caused by Mycobacterium avium subsp. paratuberculosis (MAP), can cause considerable economic losses in affected herds. Early diagnosis of JD is hampered by the chronic nature of the disease with a slow subclincal progression. The aim of the present study was to challenge the hypothesis that lymphatic fluid is of diagnostic value in the early stages of the disease. Lymphatic fluid from 122 animals was collected and tested for MAP by nested PCR for IS900 and compared to the results of testing for MAP in feces (culture), blood and milk (ELISA) in 110 of these samples. MAP was detected by PCR in 27.1% of the lymph samples. Agreement between the tests was poor: 6.9% of the lymph positive cows were also positive in all other tests applied, and 69.0% had negative results in fecal culture, blood and milk ELISA. Resampling of 25 cows after 8 to 12 and 16 to 20 months revealed 20.0% lymph positive animals at the first, 5.5% at the second and 27.8% at the third sampling, respectively. Only one cow showed positive lymph-PCR results at more than one sampling date. Lymph-positive cows had a 7.2 times greater likelihood of being culled within 8 to 12 months after sampling, compared to negative cows, mainly due to other health issues than JD. It can be concluded, that lymphatic fluid might be promising for the detection of early MAP-infection in cows, but further studies to elucidate the potential of this diagnostic approach are needed.

Short communication: evaluation of an automated in-house hematology analyzer for bovine blood

The objective of this study was to evaluate the suitability of the V-Sight hematology analyzer (A. Menarini Pharma GmbH, Vienna, Austria) for bovine blood by a comparison with a reference device (Advia 2120i, Siemens AG, Erlangen, Germany). In total, 97 blood samples were obtained from 75 dairy cows. Analyzed parameters included counts of white blood cells (WBC), lymphocytes, monocytes, granulocytes, red blood cells (RBC), and platelets (PLT), as well as hemoglobin concentration (HGB), hematocrit (HCT), mean corpuscular volume, mean corpuscular hemoglobin (MCH), MCH concentration (MCHC), mean platelet volume (MPV), and plateletcrit (PCT). Based on Passing-Bablok regression, the V-Sight provided accurate and precise results for MCH and MCHC only. The PCT results were comparable to the reference method, but precision was inconclusive. Significant proportional differences were detected for monocytes, granulocytes, HCT, and PLT. For all other analytes, significant proportional and systemic differences were observed. The WBC and lymphocyte results from the V-Sight were characterized by poor accuracy, poor precision, and a high number of false positive outliers. Bland-Altman analysis indicated negative biases for all WBC parameters, the erythrocyte indices, and PLT. Positive biases were observed for RBC, HGB, HCT, MPV, and PCT. Correlation coefficients of >0.9 between the V-Sight and the reference method were found only for RBC, HGB, HCT, and MPV. Intraassay precision of the V-Sight analyzer was acceptable (coefficient of variation <5%) for granulocytes, the erythrocyte indices, and MPV. It was unacceptable (coefficient of variation ≥5%) for WBC, lymphocytes, monocytes, as well as RBC, and inconclusive for HGB, HCT, PLT, and PCT. Sensitivity was high for all RBC counts and indices as well as PLT, but low for monocytes, granulocytes, and MPV. Specificity was high for monocytes and granulocytes, but low for RBC, HCT, MCH, and MCHC. With accurate and precise results for only 2 out of 13 parameters, the V-Sight cannot be recommended for analysis of bovine blood.

Use of an indirect sampling method to produce reference intervals for hematologic and biochemical analyses in psittaciform species

As with other animal species, comprehensive reference intervals (RI) for psittaciform species are rare and plagued by common issues, including sparse information regarding methods used to analyze specimens, low sample sizes, and improper statistical analyses. The purpose of this study was to examine the use of an indirect sampling method of RI generation from several years of data collected from specimens of multiple psittaciform species submitted to a veterinary diagnostic laboratory. These data were unselected for health status. A previously published method for indirect RI generation was applied to data collected for routine hematologic and biochemical analyses. Seven species groups were examined, and sample size ranged from 346 to 2358. Results showed that RI varied by species and appeared to represent a broader range than expected compared with other RI and traditional clinical expectations for core health assessments, such as total white blood cell count and white blood cell differential results. Some biochemical results reflected more narrow ranges, and a few were consistent with other published ranges. The intervals were likely influenced by changes related to stress and underlying disease. The results of the current study reflect the imprecision of this method related to data obtained from the population served by this laboratory. Overall, this method is not suitable for the production of comprehensive RI, although it may provide rough estimates for some limited analyses until traditional RI can be generated.

Efeitos do estresse da orquiectomia na citologia broncoalveolar de bezerros da raça Holandesa

A identificação do impacto que certas formas de estresse causam ao bem estar animal e equilíbrio orgânico, representa um desafio á adoção de boas práticas de criação. Assim, a presente pesquisa verificou o impacto de um desafio doloroso rotineiro dos bovinos na imunidade pulmonar e sistêmica. Avaliou-se hemograma e cortisol, em quatro momentos, sendo M1, M6, M7 e M8 (respectivamente sete dias antes e um, três e oito dias depois do desafio doloroso) e citologia broncolaveolar, obtida por broncoscopia, nos momentos M1, M6 e M8. Houve uma redução dos valores do eritrograma no primeiro dia após o desafio, compatível com anaplasmose e agravada pela perda de sangue durante a cirurgia e um influxo de leucócitos para a região pulmonar. Oito dias após o desafio, evidenciou-se aumento de cortisol, gerando uma leucocitose por neutrofilia e monocitose no sangue com provável redução de quimiotaxia para o pulmão, tornando o trato respiratório potencialmente mais susceptível a infecções, sugerindo que esta prática de manejo, mesmo acompanhado de protocolo analgésico, pode ser considerada um fator de risco a penumonias afetando o bem estar animal.

Evaluation of total white blood cell count as a marker for proviral load of bovine leukemia virus in dairy cattle from herds with a high seroprevalence of antibodies against bovine leukemia virus

OBJECTIVE

To determine the reference interval for WBC counts in Holstein dairy cows from herds with high seroprevalence for anti-bovine leukemia virus (BLV) antibodies, analyze the correlation of total WBC counts and blood proviral load (bPVL) in BLV-infected animals, and determine whether total WBC count can be used a hematologic marker for in vivo infection.

ANIMALS

307 lactating cows from 16 dairy herds with high BLV seroprevalence.

PROCEDURES

Blood samples were collected for assessment of plasma anti-BLV p24 antibody concentration (all cows), manual determination of WBC count (161 BLV-seronegative cows from 15 herds), and evaluation of bPVL (146 cows from another herd).

RESULTS

The WBC count reference interval (ie, mean ± 2 SD) for BLV-seronegative dairy cows was 2,153 to 11,493 cells/μL. Of the 146 cows used to analyze the correlation between WBC count and bPVL, 107 (73%) had WBC counts within the reference interval; of those cows, only 21 (19.6%) had high bPVL. Most cows with high WBC counts (35/39) had high bPVL. Mean WBC count for cows with high bPVL was significantly higher than values for cows with low or undetectable bPVL. White blood cell counts and bPVL were significantly (ρ = 0.71) correlated.

CONCLUSIONS AND CLINICAL RELEVANCE

These data have provided an updated reference interval for WBC counts in Holstein cows from herds with high BLV seroprevalence. In dairy cattle under natural conditions, WBC count was correlated with bPVL; thus, WBC count determination could be a potential tool for monitoring BLV infection levels in attempts to control transmission.

Hematologic and IgG responses of heifers experimentally infected with the agent of epizootic bovine abortion

BACKGROUND

Epizootic bovine abortion (EBA) is a tick-transmitted abortive disease of beef cattle in the western United States. Infected cattle do not have clinical signs until abortion occurs, usually within the last trimester of gestation. There is little information on the hematologic response of the dam following infection.

OBJECTIVE

The purpose of this study was to determine if changes in blood leukocytes and serum IgG concentrations could be detected following experimental infection of pregnant heifers with the etiologic agent of EBA (aoEBA).

METHODS

Twelve Angus heifers were infected during gestation with the aoEBA using an inoculum prepared from the thymus of an infected fetus. Five pregnant heifer controls were given an inoculum prepared from the thymus of an aoEBA-negative calf. PCVs, total and differential leukocyte counts, and serum IgG concentrations were measured weekly following administration of the inocula until abortion or calving. Gross and microscopic examinations were performed on all aborted fetuses to confirm infection.

RESULTS

Eleven of 12 heifers in the treatment group aborted, and significant findings were decreased lymphocyte counts at weeks 1 and 14 postinoculation and increased monocyte counts at week 4 compared with control animals. Serum IgG concentrations were significantly increased at weeks 6-8 and 11 in the treatment group.

CONCLUSIONS

Leukogram changes are subtle in infected cattle. Future research efforts should be aimed at development of an antibody test specific for detection of previously infected animals, which could graze safely on EBA-endemic pastures.

Age-related changes in biochemical and hematologic variables in Borzoi and Beagle puppies from birth to 8 weeks

BACKGROUND

Nonspecific signs of illness and availability of only limited information about expected biochemical and hematologic values in puppies make formulation of a differential diagnosis challenging for veterinarians.

OBJECTIVES

The objectives of this prospective study were to describe age-related changes in biochemical and hematologic variables in Borzoi and Beagle puppies from birth to 8 weeks and to compare results with adult reference intervals (RIs).

METHODS

Biochemical and hematologic analytes in blood collected in heparin and EDTA from 31 clinically healthy puppies (21 Beagle and 10 Borzoi dogs) were measured or calculated each week from birth to 8 weeks of age. RIs were calculated using the parametric robust method after Box-Cox transformation.

RESULTS

There were no significant differences between values of puppies and adults for ALT activity, glucose concentration, MCHC, WBC count, and platelet count. Total protein concentration, RBC count, and HCT were lower and creatine kinase activity was higher in puppies of all ages compared with these variables in adults. Compared with adult RI, in puppies urea concentration was higher at birth and week 1, creatinine concentration was lower at weeks 1-5, ALP activity was higher at all weeks except for weeks 4 and 6, hemoglobin concentration was lower at weeks 1-8, MCV was higher at birth and week 1, and reticulocyte count was higher at all weeks except week 1. Statistically, mixed models accounted for evaluation of the same puppies each week and in most cases demonstrated an effect of age and sometimes breed. Some reference intervals should be used with caution owing to potential outliers. The 90% confidence intervals exceeded those recommended by the International Federation of Clinical Chemistry.

CONCLUSIONS

Clinicians should be aware of temporal changes in biochemical and hematologic values for puppies during the first 2 months of life to avoid misinterpretation of results.

Effect of infection with bovine leukosis virus on lymphocyte proliferation and apoptosis in dairy cattle

OBJECTIVE

To determine effects of infection with bovine leukosis virus (BLV) on lymphocyte proliferation and apoptosis in dairy cattle.

ANIMALS

27 adult Holstein cows.

PROCEDURES

Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood from lactating Holstein cows seronegative for BLV (n = 9 cows), seropositive for BLV and aleukemic (aleukemic; 9), and seropositive for BLV and persistently lymphocytotic (PL; 9). Isolated PBMCs were assayed for mitogen-induced proliferation and were analyzed by means of flow cytometry. The PBMCs from a subset of each group were assayed for apoptosis, caspase-9 activity, and expression of selected genes related to apoptosis.

RESULTS

PL cows had significantly higher total lymphocyte counts and significantly lower proportions of T-lymphocyte populations than did BLV-negative and aleukemic cows. Both groups of BLV-infected cows had significantly higher proportions of B cells and major histocompatibility complex II-expressing cells than did BLV-negative cows. Proliferation with concanavalin A was significantly lower for PL cows, compared with proliferation for BLV-negative cows. Pokeweed mitogen-induced proliferation was significantly higher for aleukemic and PL cows than for BLV-negative cows. Gene expression of apoptosis-inhibitory proteins BCL2 and BCL2L1 was significantly higher for aleukemic cows and expression of BCL2 was significantly higher for PL cows than for BLV-negative cows.

CONCLUSIONS AND CLINICAL RELEVANCE

Cattle infected with BLV had marked changes in PBMC populations accompanied by alterations in proliferation and apoptosis mechanisms. Because the relative distribution and function of lymphocyte populations are critical for immune competence, additional studies are needed to investigate the ability of BLV-infected cattle to respond to infectious challenge.

Reference Intervals for Total Protein Concentration, Serum Protein Fractions, and Albumin/Globulin Ratios in Clinically Healthy Dairy Cows

The aim of the current study was to evaluate total serum protein concentration measured by the biuret reaction as well as albumin and globulin protein fractions determined by agarose gel electrophoresis. These data were used to establish reference intervals in dairy cows of different ages. Blood was collected from 111 clinically healthy Modicana dairy cows by means of jugular venipuncture. Reference intervals (mean ± standard deviation) were determined for total protein (67.54 ± 11.53 g/l), albumin (31.86 ± 4.60 g/l), α1-globulin (5.77 ± 2.20 g/l), α2-globulin (5.84 ± 1.90 g/l), β-globulin (7.46 ± 1.94 g/l), and γ-globulin (16.73 ± 4.54 g/l) concentrations as well as for albumin/globulin (A/G) ratio (0.88 ± 0.43). Values from 2-, 3-, 4-, 5-, and 6-year-old cows were compared statistically. One-way analysis of variance showed age-related differences for α-globulin and β-globulin fractions only. The results of the current study provide reference intervals for total protein concentration as well as albumin and globulin protein fractions in 2- to 6-year-old dairy cows.