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Evaluating different methods of serum collection to detect failed transfer of passive immunity in newborn calves via
N Sonntag1, S Borchardt1, W Heuwieser1
1Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universität Berlin, Königsweg 65, 14163 Berlin, Germany.
Insights
Four serum collection methods accurately assess failed transfer of passive immunity (FTPI) in dairy calves using Brix refractometry. Clotted serum is comparable to centrifuged serum, but avoid refrigerated clotting due to hemolysis risk.
Area of Science:
- Veterinary Immunology
- Dairy Science
- Neonatal Calf Health
Background:
- Failed transfer of passive immunity (FTPI) in dairy calves is a significant concern, impacting calf health and survival.
- Accurate and accessible methods for assessing immunoglobulin G (IgG) levels are crucial for early FTPI detection.
- Brix refractometry offers a potentially rapid and cost-effective alternative to traditional laboratory analyses.
Purpose of the Study:
- To compare the accuracy of four serum collection and processing methods for assessing FTPI in dairy calves.
- To evaluate the correlation between Brix refractometry measurements and gold-standard radial immunodiffusion (RID) for IgG concentration.
- To determine the optimal serum collection method for reliable FTPI assessment in neonatal dairy calves.
Main Methods:
- Blood samples were collected from 321 newborn dairy calves.
- Serum was processed using four methods: centrifugation, filtration, room temperature clotting, and refrigerated temperature clotting.
- Total solids (TS) in % Brix and IgG concentrations via RID were measured for each serum type.
Main Results:
- All tested serum types (centrifuged, room temp clotted, refrigerated temp clotted, filtered) showed high correlations with IgG concentration via RID.
- Total solids measurements using Brix refractometry were highly correlated across all serum types compared to centrifuged serum.
- Clotted serum (both room and refrigerator temperatures) demonstrated accuracy comparable to centrifuged serum, while filtered serum was slightly less accurate.
Conclusions:
- All four serum collection methods are valid for detecting FTPI in dairy calves when appropriate Brix thresholds are used.
- Clotted serum offers accuracy comparable to centrifuged serum, making it a viable option.
- Refrigerated temperature clotting should be avoided due to potential hemolysis, which can affect results.
Abstract:
The objective of the study was to compare 4 different methods of serum collection to assess failed transfer of passive immunity (FTPI) in dairy calves. We hypothesized that centrifuged serum, filtered serum and clotted serum at room temperature, and clotted serum at refrigerator temperature measured with Brix refractometry would highly correlate with IgG concentration assessed by radial immunodiffusion (RID; gold standard) in centrifuged serum. Blood samples were collected from 321 newborn dairy calves. In centrifuged serum (r = 0.88), serum clotted at room temperature (20.2°C ± 6.47; r = 0.86), serum clotted at refrigerator temperature (7.6°C ± 0.91; r = 0.87), and filtered serum (r = 0.70), total solids (TS) in % Brix, and IgG concentrations measured with RID were highly correlated. Regarding the refractometry results among the different serum types, the TS results of serum clotted at room temperature, clotted at refrigerator temperature, and filtered serum showed high correlation coefficients compared with the TS results of centrifuged serum (r = 0.99, r = 0.98, and r = 0.89), respectively. The test characteristics of clotted serum were as accurate as centrifuged serum and generate comparable results. Filtered serum was slightly less accurate. All serum types are valid methods to detect an FTPI in dairy calves, if the specific Brix thresholds for each serum type are considered. Nevertheless, serum clotted at refrigerator temperature should not be the preferred method to avoid the risk of hemolysis.
