Use of clinic refractometer at farm as a tool to estimate the IgG content in goat colostrum

Noemí Castro,Lenny Andrea Gómez-González,Bernadette Earley,Anastasio Argüello

doi:10.1080/09712119.2018.1546585

Abstract

ABSTRACTRefractometry has been proposed as a farm technique to estimate the IgG concentration in colostrum. In order to validate the method in goat colostrum using a clinical refractometer, 216 colostrum and milk samples were obtained from 54 dairy goats. Samples were evaluated for protein concentration using a clinical refractometer and IgG concentration was measured using a commercial ELISA. The r2 for the linear regression between refractometry value and IgG concentration measured by ELISA was 0.79, and the area under the receiver operating characteristics curve was 0.99. The proposed cut-off value using the clinical refractometer was 10 mg/mL. At this point, the sensitivity, specificity, negative predictive value, positive predictive value, Youden’s index and accuracy were 100%, 95.19%, 100%, 76.32%, 0.95% and 95.83%, respectively.

Highlights

Goat kids are hipogammaglobulinaemic at birth due to the special characteristic of the synepitheliochorial placenta that did not allow the IgG transport from the goat to the goat kid (Castro et al 2011)
In order to validate the method in goat colostrum using a clinical refractometer, 216 colostrum and milk samples were obtained from 54 dairy goats
The r2 for the linear regression between refractometry value and IgG concentration measured by ELISA was 0.79, and the area under the receiver operating characteristics curve was 0.99

Summary

Introduction

Goat kids are hipogammaglobulinaemic at birth due to the special characteristic of the synepitheliochorial placenta that did not allow the IgG transport from the goat to the goat kid (Castro et al 2011) This anatomical and physiological characteristic gives to colostrum an essential role in the neonate immunity. Due to all of these factors, the colostrum IgG concentration must be checked before to feed the animals in order to reduce the presence of Failure of Passive Transfer cases and assure a good health and growth in the ruminant neonates in the modern dairy farms. For the past 10 years, refractometry has been used for determining the IgG concentration in the colostrum in farms (Chigerwe et al, 2008; Quigley et al 2013) observing a significant correlation between Brix index and colostrum IgG concentration in dairy cows. As the literature is limited in reference to the use of clinical refractometer for measuring colostrum IgG in dairy goats, the present study was conducted

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