Acute phase proteins as indicators of calf herd health

The potential for using acute phase proteins (APPs) in the assessment of herd health was studied by examining the levels of serum haptoglobin, serum amyloid A (SAA) and plasma fibrinogen in relation to clinical findings and leukocyte counts in calves. Two groups of calves from conventional dairy farms were studied. The animals were examined 10 times during the first six weeks after introduction into a new environment. Haptoglobin, SAA and fibrinogen were analysed and weight gain, disease symptoms and treatments were recorded. Analysis of antibodies against viral infections was performed. An acute phase reaction (APR) score was established at each sampling by combining the APP results and total leukocyte counts. The health status differed between the two groups, although no manipulation of health had been performed, except that the group with a higher incidence of disease had a concurrent experimental infection with lungworm as part of another study. In the group with a higher incidence of disease, the mean weight gain was significantly lower, and the number of sampling days with elevated serum concentrations of APPs, and the mean maximum concentrations of haptoglobin and fibrinogen were significantly higher compared to the healthier group. The APR score was significantly higher at days 4 and 8 of the study in the group with a higher incidence of disease. The results indicate that measurement of APPs could be a useful tool for evaluation of health in calf herds.     

The use of receiver operating characteristic (ROC) analysis to assess the diagnostic value of serum amyloid A, haptoglobin and fibrinogen in traumatic reticuloperitonitis in cattle

Acute phase proteins (APPs) such as serum amyloid A (SAA), haptoglobin (Hp), and plasma fibrinogen (Fb) are diagnostic and prognostic biomarkers. This study determined the pattern of SAA in traumatic reticuloperitonitis (TRP) in cows, and compared the findings with Hp, and plasma Fb concentrations in the differential diagnosis of TRP using receiver operating characteristic (ROC) analysis. Blood samples were collected from 89 cows: 53 cases of TRP, 16 animals with other internal disorders and 20 healthy controls.SAA and Hp had a similar pattern and magnitude of changes in TRP. Using the ROC method, the optimal cut-off for the diagnosis of TRP was 68 μg/mL for SAA and 0.74 g/L for Hp, with 100% sensitivity and 86.1% specificity; either of these parameters may therefore be used as a sensitive and relatively specific tool for the differential diagnosis of TRP in cattle. The diagnostic accuracy of plasma Fb was significantly lower than either SAA or Hp (P < 0.01). The combined use of these APPs (whilst aware of their conditional interdependence) may not provide any additional diagnostic information than can be obtained using either SAA or Hp alone.     

Serum Amyloid A and Haptoglobin Concentrations and Liver Fat Percentage in Lactating Dairy Cows with Abomasal Displacement

Background: There has been increased interest in measuring the serum concentration of acute phase reactants such as serum amyloid A [SAA] and haptoglobin [haptoglobin] in periparturient cattle in order to provide a method for detecting the presence of inflammation or bacterial infection.
Objectives: To determine whether [SAA] and [haptoglobin] are increased in cows with displaced abomasum as compared with healthy dairy cows.
Animals: Fifty-four adult dairy cows in early lactation that had left displaced abomasum (LDA, n = 34), right displaced abomasum or abomasal volvulus (RDA/AV, n = 11), or were healthy on physical examination (control, n = 9).
Materials and Methods: Inflammatory diseases or bacterial infections such as mastitis, metritis, or pneumonia were not clinically apparent in any animal. Jugular venous blood was obtained from all cows and analyzed. Liver samples were obtained by biopsy in cattle with abomasal displacement.
Results: [SAA] and [haptoglobin] concentrations were increased in cows with LDA or RDA/AV as compared with healthy controls. Cows with displaced abomasum had mild to moderate hepatic lipidosis, based on liver fat percentages of 9.3 ± 5.3% (mean ± SD, LDA) and 10.8 ± 7.7% (RDA/AV). [SAA] and [haptoglobin] were most strongly associated with liver fat percentage, r _s=+0.55 ( P < .0001) and r _s=+0.42 ( P = .0041), respectively.
Conclusions and Clinical Importance: An increase in [SAA] or [haptoglobin] in postparturient dairy cows with LDA or RDA/AV is not specific for inflammation or bacterial infection. An increase in [SAA] or [haptoglobin] may indicate the presence of hepatic lipidosis in cattle with abomasal displacement.     

A Comparison of Elevated Blood Parameter Values in a Population of Thoroughbred Racehorses

In racing Thoroughbred horses, blood cell counts and key biochemistry parameters are used to monitor horse health during training. The most common measure is total white blood cell (WBC) count, usually coupled with estimates of the relative abundance of the five main types of WBC. However, WBC can go down and up when challenged, making interpretation difficult. In contrast, a large majority of health issues that impact training should trigger an inflammatory response. In this study, we test the potential for two inflammatory biomarkers, fibrinogen and serum amyloid A (SAA), to provide more reliable indicators of health issues across a large sample of horses in training. We find that although WBC and other cell counts are generally correlated with each other and other biochemistry parameters across their full range of values, fibrinogen and SAA exhibit the greatest concordance among the top 15% of values. Moreover, horses with the top WBC values do not overlap significantly with those having the top fibrinogen and SAA values. Because most horses are healthy, these patterns suggest that natural variation in cell counts and biochemistry largely occlude values that might indicate health issues. In contrast, the subset of unusual horses with elevated levels of both fibrinogen and SAA are strongly suggestive of the expected handful of animals with minor, undetected issues. We conclude that fibrinogen and SAA have excellent potential as biomarkers and are likely to be more informative about conditions relevant to horses in training compared with the widely used WBC.     

Selected Biochemical Indicators of Equine Rhabdomyolysis in Arabian Horses: Acute Phase Proteins and Trace Elements

Although creatine kinase (CK), aspartate transaminase (AST), cytokines, and oxidative stress parameters were shown to be useful biomarkers for diagnosis of equine rhabdomyolysis, additional biomarkers of the disease may be of interest to indicate prognosis of the disease. Therefore, the present study investigated acute phase proteins and trace elements as additional biomarkers of ER. Sixty male horses (4-6 years old) of 2 equal groups were used. Horses of the first group were clinically healthy and served as a control group, whereas horses of the second group were ER-diseased animals. Harvested sera were used for estimation of the activities of CK, AST, lactate dehydrogenase (LDH), serum amyloid A (SAA), haptoglobin (Hp), ceruloplasmin (Cp), copper, iron, and zinc, whereas plasma samples were used for determination of fibrinogen. The present findings revealed a significant (P ≤ .05) increase in values of CK, AST, and LDH in diseased horses compared to those in control values. In addition, a significant (P ≤ .05) increase in SAA (162.6 ± 5.32 mg/L), Hp (3.6 ± 0.54 g/L), Cp (39.32 ± 2.31 mg/L), and copper (28.36 ± 1.23 μmol/L) along with a significant (P ≤ .05) reduction in levels of iron (9.32 ± 0.23 μmol/L) and zinc (8.65 ± 1.02 μmol/L) was recorded in diseased horses compare to that in controls (11.3 ± 2.2 mg/L, 0.8 ± 0.2 g/L, 24.23 ± 1.32 mg/L, 18.41 ± 1.03 μmol/L, and 14.2 ± 0.42 μmol/L, respectively). In conclusion, SAA, Hp, Cp, copper, and zinc were useful prognostic biomarkers for the diagnosis of ER in Arabian horses.     

Analytical validation of commercially available methods for acute phase proteins quantification in pigs

The aim of this study was to validate commercially available methods for porcine haptoglobin (Hp), C-reactive protein (CRP), serum amyloid A (SAA) and major acute phase protein (Pig-MAP) determinations. Intra and inter assay coefficients of variation (CVs) were lower than 20% in all cases with exception of inter assay CVs for CRP and Pig-MAP assays with samples of low acute phase proteins concentration, and for SAA assay at any acute phase proteins concentration. All methods showed good linearity and detection limits were low enough to detect APPs levels in healthy animals. Hp and SAA were very affected by haemolysis. Lipaemia influenced mainly on SAA determination. Over 15-fold increase was observed in CRP and SAA concentrations after artificially induced inflammation by a single subcutaneous dose of turpentine, whereas Hp and Pig-MAP increased less than 5-fold.     

Acute phase proteins assessment for an early selection of treatments in growing calves suffering from bronchopneumonia under field conditions

Blood samples were taken from calves with respiratory disease the first day of examination for determination of the serum concentration of haptoglobin, fibrinogen, alpha-2- and gamma-globulins, and albumin. A clinical examination was performed daily for the duration of the disease. The animals were retrospectively classified in two categories: those animals requiring no treatment or antibiotics alone (group A), and antibiotics associated to anti-inflammatory drugs (group B). The serum proteins were tested in order to check whether they were able to distinguish, on the first day of clinical examination, between calves requiring anti-inflammatory treatment (group B) or not (group A). About 80% of calves were properly classified in both groups by the combined use of the two serum proteins haptoglobin and fibrinogen: these two proteins, and especially haptoglobin, were useful for the identification of calves requiring an anti-inflammatory treatment.     

Renal amyloidosis in cattle with inflammatory diseases

BACKGROUND: The association of inflammatory diseases such as traumatic reticuloperitonitis (TRP), mastitis, metritis, and pododermatitis with renal amyloidosis in cattle is poorly described. HYPOTHESIS: Serum amyloid A (SAA) levels are elevated during inflammatory diseases, and renal amyloidosis is formed as a complication. ANIMALS: This study was conducted with 82 crossbred cattle with mastitis (n = 18 cows), metritis (n = 11 cows), TRP (n = 30 cows), and pododermatitis (n = 23 : 15 cows and 8 beef cattle). Ten clinically healthy cows served as controls. Methods: Hematological, urinary, and blood parameters, including SAA, were measured by an automated procedure provided with trade kits. Determination of amyloidal structures was made by histopathological examination of renal biopsy specimens. RESULTS: At the end of this trial, amyloidosis was detected in 5 cows displaying typical nephrotic syndrome, with hypoproteinemia and proteinuria in combination with polyuria and weight loss. Furthermore, it was observed that cows with renal amyloidosis had significantly higher (P < .01) total leukocyte counts, serum and urine enzyme activities, and urea and creatinine concentrations, with lower serum total protein concentrations, when compared with animals without renal amyloidosis. CONCLUSIONS AND CLINICAL IMPORTANCE: The incidence of AA amyloidosis in cattle in this study suggests that cattle with mastitis, metritis, and pododermatitis have a high prevalence of systemic amyloidosis in response to inflammation.