Evaluation of an ELISA and four on-farm tests to estimate colostrum quality for dairy cows.

The objectives of this study were to evaluate different analytical methods determine colostrum quality in dairy cattle, including one laboratory-based method (ELISA) and 4 on-farm tests. We hypothesized that the colostral immunoglobulin G (IgG) concentration using methods, i.e., ELISA (mg/mL), digital Brix refractometer (% Brix), colostrometer (specific gravity mg/mL), an outflow funnel (seconds), a lateral flow assay (mg/mL) highly correlated with reference method, radial immunodiffusion (RID; mg/mL) would generate comparable results. Colostrum samples collected from 209 Holstein Friesian cows on 2 commercial farms Germany. weight temperature measured. Test characteristics, such as optimum thresholds, sensitivity (Se), specificity (Sp), area under curve (AUC) determined receiver operating characteristic (ROC) analyses for each test.Out assessed by RID, 186 (89%) had high (≥50 mg IgG/mL), while 23 (11%) showed poor IgG concentrations less than 50 mg/mL. mean (±SD) was 101.3 ± 45.9 mg/mL range 6.0 244.3 IgG/mL. Pearson correlation coefficient between RID r = 0.78. In comparison coefficients tests were: 0.79 (digital refractometry), 0.58 (colostrometer: specific gravity), 0.61 corrected), 0.26 (outflow funnel) 0.43 (lateral assay), respectively. optimal threshold identify high-quality at 50.8 91.3%, 92.3%, AUC 0.94. For ranged 95.7% (Brix refractometry) 60.9% assay). Specificity 88.6% assay) 75.9% (colostrometer after correction). 0.93 0.73 funnel). Based AUC, (0.94) refractometry (0.93) can be considered accurate.In conclusion, is accurate assess quality. Regarding only adequate