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Evaluation of 5 methods for diagnosing failure of passive transfer in 160 Holstein calves
Author(s) -
Zakian Amir,
Nouri Mohammad,
Rasooli Aria,
Ghorbanpour Masoud,
Constable Peter D.,
MohammadSadegh Majid
Publication year - 2018
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/vcp.12603
Subject(s) - refractometry , refractometer , brix , biuret test , receiver operating characteristic , kappa , medicine , zoology , mathematics , chemistry , biology , food science , biochemistry , materials science , geometry , sugar , optoelectronics , urea , refractive index
Background Inadequate absorption of colostral IgG 1 is termed failure of transfer of passive immunity ( FTPI ). Dairy calves with FTPI have increased mortality and morbidity in their first 6 months of life. Objectives This study compared the clinical performance of 5 methods for diagnosing FTPI in Holstein calves. Methods An observational study was performed using 160 Holstein heifer calves. Serum was harvested at 48 hours of age, and FTPI was assessed using a digital Brix refractometer for total solids measurements, and digital refractometry and the biuret method to measure serum total protein ( STP ) concentrations. Serum gamma‐glutamyltransferase activity was measured with an automated analyzer, and serum IgG was measured with the zinc sulfate turbidity test and an enzyme‐linked immunosorbent assay. Diagnostic test performance was compared with that of the reference method ( FTPI defined as a serum total IgG concentration <10 g/L). Test performance was evaluated using the area under the receiver operating characteristic curve, the sensitivity, the specificity, and the positive likelihood ratio at the optimal test cut point, and by calculating the kappa coefficient. Results A serum digital Brix percentage of <7.8% and an STP concentration of <52 g/L measured using digital refractometry were the best methods to identify calves with FTPI . The STP concentration measured with digital refractometry was 0.1 g/L lower than that measured with the biuret method. Conclusions The digital Brix refractometer and the digital refractometer provide accurate and clinically useful methods for identifying dairy calves with FTPI . In this study, the excellent performance of the Brix refractometer was likely due to the use of a fixed sample volume (200 μL) and a uniform sample temperature at the time of measurement.