Comparison of single radial immunodiffusion and ELISA for the quantification of immunoglobulin G in bovine colostrum, milk and calf sera

Amanda Dunn,Catherine Duffy,Alan Gordon,Steven Morrison,Anastasio Argűello,Michael Welsh,Bernadette Earley

doi:10.1080/09712119.2017.1394860

Abstract

ABSTRACTThe overall objective was to compare immunoglobulin G (IgG) concentrations measured by single radial immunodiffusion (sRID) and ELISA-based methods in samples of bovine colostrum and transition milk from contrasting breed types (Limousin × Friesian (n = 10) and Holstein (n = 10)). Jugular blood samples were collected at 48 h post-birth from beef (n = 10) and dairy (n = 10) calves and sera harvested subsequent to colostrum consumption. Absolute colostrum IgG values determined by ELISA showed poor agreement with mean (SD) IgG values measured using sRID, fixed bias (sRID – ELISA) was 31.89 (±9.84) mg/mL; having wide limits of agreement (12.61–51.17) and a low concordance coefficient (0.26). The agreement between ELISA and sRID when measuring serum IgG was greater than that of colostrum, fixed bias (sRID – ELISA) was 12.36 (±6.60) mg/mL; having narrower limits of agreement (−0.58 to 25.30) and serum IgG concentrations had a greater concordance coefficient (0.44) between samples. Calf sera IgG measured using the indirect zinc sulphate turbidity test showed a strong correlation with the sRID and ELISA methods (P < .001), R2 = 0.78 and R2 = 0.77 respectively. Overall, the ELISA and sRID methodologies had a strong positive association with almost a twofold (1.8) difference between values; therefore, they provide diverse absolute values of IgG concentration.

Highlights

Immunoglobulin G (IgG) is the most abundant isotype found in bovine colostrum and represents over 75% of the total immunoglobulin (Ig) concentration (Korhonen et al 2000), and quality of colostrum is assessed with reference to the content of this specific Ig class
There was a positive correlation between the enzyme-linked immunosorbent assay (ELISA) and single radial immunodiffusion (sRID) methods; IgG concentration in first milking colostrum (R2 = 0.83; P < .001) and calf serum at 48 h postbirth (R2 = 0.97; P < .001)
The IgG values determined by sRID were approximately 1.8 times greater than the values produced using the ELISA method when assessing colostrum and calf sera IgG concentration

Summary

Introduction

Immunoglobulin G (IgG) is the most abundant isotype found in bovine colostrum and represents over 75% of the total immunoglobulin (Ig) concentration (Korhonen et al 2000), and quality of colostrum is assessed with reference to the content of this specific Ig class. Several studies have reported calves with FPT to be at greater risk of neonatal morbidity, pre-weaning morbidity and mortality compared to calves which achieved adequate passive transfer (APT) at 24 h (Donovan et al 1998; Tyler et al 1999; Godden et al 2009). FPT is a major problem in Ireland, with 56% of samples submitted by private veterinary practitioners and from dead calves submitted for post mortem returning values consistent with FPT (DAFM/AFBI 2015). It has been established by several researchers (Kehoe et al 2007; Morrill et al 2012; Conneely et al 2013) that colostrum quality is extremely variable between individual cows and herds. An Irish study looking at different genotypes of beef suckler cows have reported colostral IgG concentrations > 150 mg/mL from both Charolais and beef × dairy cross breeds; this is sufficient to provide APT to the calf providing the calf is supervised during the period after birth to ensure suckling occurs (McGee et al 2005)

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Conclusion