Evaluation of a Brix refractometer to estimate serum immunoglobulin G concentration in neonatal dairy calves

Abstract

The objective of this study was to evaluate the utility of a digital Brix refractometer for the assessment of success of passive transfer of maternal immunoglobulin compared with the measurement of serum total protein (STP) by refractometry. Blood samples (n = 400) were collected from calves at 3 to 6d of age. Serum IgG concentration was determined by radial immunodiffusion (RID), and STP and percentage Brix (%Brix) were determined using a digital refractometer. The mean IgG concentration was 24.1g/L [standard deviation (SD) ± 10.0] with a range from 2.1 to 59.1g/L. The mean STP concentration was 6.0 g/dL (SD ± 0.8) with a range from 4.4 to 8.8 g/dL. The mean %Brix concentration was 9.2% (SD ± 0.9) with a range of 7.3 to 12.4%. Brix percentage was highly correlated with IgG (r = 0.93). Test characteristics were calculated to assess failure of passive transfer (FPT; serum IgG <10 g/L). The sensitivity and specificity of STP at 5.5 g/dL were 76.3 and 94.4%, respectively. A receiver operating characteristic curve was created to plot the true positive rate against the false positive rate for consecutive %Brix values. The optimal combination of sensitivity (88.9%) and specificity (88.9%) was at 8.4% Brix. Serum total protein was also positively correlated with %Brix (r = 1.00) and IgG (r = 0.93). Dairy producers can successfully monitor their colostrum management and the overall success of passive transfer using a digital Brix refractometer to estimate IgG concentration of colostrum and calf serum.

Brix Refractometry of Colostrum from Primiparous Dairy Cows and New-Born Calf Blood Serum in the Evaluation of Failure of Passive Transfer

“…Its advantages were previously described by Wallace et al [42] who reported that the results of refractometry from centrifuge-and noncentrifugeharvested sources of serum were highly correlated so producers can conduct this test on-farm without the need of a centrifuge. Similar to results of Deelen et al [41], our results showed that % Brix highly correlated with the concentration of serum IgG, when all calves where considered, independently of the serum IgG concentration. This result undoubtedly showed that Brix refractometry can be used for assessing FPT.…”

“…This result undoubtedly showed that Brix refractometry can be used for assessing FPT. Also, similar to Deelen et al [41] we found a correlation between % Brix and total serum proteins when all sera were included in the calculation. However, when we analyzed sera of calves with FPT (<10 g/L IgG) we did not fi nd a signifi cant correlation between % Brix and the concentration of total serum proteins.…”

“…Knowing that the Brix refractometer can be used to measure IgG concentrations in the calf serum [41] we have investigated further options for its application on our farms. Its advantages were previously described by Wallace et al [42] who reported that the results of refractometry from centrifuge-and noncentrifugeharvested sources of serum were highly correlated so producers can conduct this test on-farm without the need of a centrifuge.…”

Quantification of bovine immunoglobulin G using transmission and attenuated total reflectance infrared spectroscopy

“…In comparison, these values are higher than those reported previously for counterpart TIR-based assays for equid IgG 21,32 and camelid IgG levels, 3 and for the ATR-IR method described for canine IgG concentrations. 40 Furthermore, the correlation coefficients between IgG concentrations predicted by both IR spectroscopic methods and the reference RID IgG assay were higher than those reported for refractometry, 9,28 similar to those of near-IR spectroscopy, 52 but lower than the value reported for automated turbidimetric immunoassay. 1 The level of agreement between results from the 2 IR spectroscopic methods and the RID assay for detecting FPTI was high, as assessed using kappa statistics (Table 2).…”

A survey of dairy calf management practices in some producing regions in Brazil

“…A way to evaluate the efficiency of the supply of colostrum R. Bras. Zootec., 44(10): [361][362][363][364][365][366][367][368][369][370]2015 is by monitoring the serum protein of newborns by using a refractometer of brix or of protein (Deelen et al, 2014). These tools have a very low cost, even though 98% of producers did not monitor the serum protein.…”