Evaluation of a cow-side immunoassay kit for assessing IgG concentration in colostrum.
OBJECTIVE
To determine sensitivity and specificity of a cow-side immunoassay kit for assessing IgG concentration in colostrum.


METHODS
Prospective study.


METHODS
76 dairy and 11 beef cows of various parities.


METHODS
Colostrum from first, second, and third milkings and milk samples were collected, and IgG concentration was determined by means of radial immunodiffusion. The immunoassay was performed according to the manufacturer's instructions, and sensitivity and specificity were calculated by comparing results of the immunoassay (positive vs negative) with results of immunodiffusion (< 50 g/L vs > or = 50 g/L).


RESULTS
135 colostrum or milk samples were collected. Mean +/- SD colostral IgG concentrations, determined by means of radial immunodiffusion for dairy and beef cows were 65.4 +/- 51.4 g/L and 114.8 +/- 42.7 g/L, respectively. Mean IgG concentrations for first-, second-, and third-milking colostrum samples and for milk samples were 92 +/- 49.0 g/L, 74.6 +/- 45.1 g/L, 47.5 +/- 32 g/L, and 6.8 +/- 3.8 g/L, respectively. Sensitivity of the immunoassay (ie, percentage of samples with IgG concentration < 50 g/L with a positive immunoassay result) was 93%, and specificity (ie, percentage of samples with IgG concentration > or = 50 g/L with a negative immunoassay result) was 76%.


CONCLUSIONS
Results suggested that the immunoassay kit was an acceptable cow-side test to identify colostrum samples with IgG concentrations < 50 g/L. The immunoassay kit should be useful in screening colostrum for adequate IgG concentration before feeding to calves or storage.
Chigerwe
Munashe
M
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
Dawes
Maisie E
ME
Tyler
Jeff W
JW
Middleton
John R
JR
Moore
Malantus P
MP
Nagy
Dusty M
DM
D000818:Animals; D002417:Cattle / Q000276:immunology* / Q000502:physiology; D003126:Colostrum / Q000276:immunology*; D005260:Female; D007118:Immunoassay / Q000379:methods / Q000592:standards / Q000662:veterinary*; D005779:Immunodiffusion / Q000379:methods / Q000662:veterinary; D007074:Immunoglobulin G / Q000032:analysis*; D007774:Lactation / Q000276:immunology; D008892:Milk / Q000276:immunology; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
D007074:Immunoglobulin G; D011933:Reagent Kits, Diagnostic