Publikationsdatenbank

Diagnosis of failure of passive transfer in dairy calves and procedures after calving to improve harvesting of high-quantity and high-quality colostrum (2021)

Art

Hochschulschrift

Autor

Sutter, Franziska (WE 19)

Quelle

Berlin, 2021 — 189 Seiten

Sprache

Englisch

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/31214

Kontakt

Tierklinik für Fortpflanzung

Königsweg 65
Haus 27
14163 Berlin
+49 30 838 62618
fortpflanzungsklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

The overall objectives of this thesis were (1) to evaluate a filter system to harvest plasma for identification of failure of passive transfer in newborn calves, (2) to evaluate 2 different treatment procedures after calving to improve harvesting of high-quantity and high-quality colostrum, and (3) to evaluate different analytical methods to assess failure of passive transfer in neonatal calves. To validate a filter system to harvest plasma for the assessment of failure of passive transfer (FPT) in neonatal calves, venous blood samples (serum and plasma) were withdrawn from 227 Holstein Friesian calves aged 1 to 7 d. Serum IgG concentrations were determined using a sandwich enzyme-linked immunosorbent assay (ELISA) (gold standard), and failure of passive transfer was defined as IgG concentrations below 10 mg/mL. Serum was obtained through centrifugation, and plasma was extracted either through centrifugation or a disposable filter system (2-Drop-Filter, Pharmadoc, Lübeck, Germany). To assess the total proteins (TP) and total solids (TS) in serum and plasma, a handheld optical refractometer (Euromex Holland, Arnhem, the Netherlands) and 2 digital Brix refractometers (device 1: HI 96801 digital refractometer, Hanna Instruments, Woonsocket, RI; device 2: Misco PA201, Misco, Solon, OH) were used. The optimal threshold for each device and each medium, i.e centrifuged serum, centrifuged plasma, and filtered plasma, was calculated using the receiver operating characteristic (ROC) curve analyses. The prevalence of failure of passive transfer in neonatal calves was 30% (67/227). The optimal threshold for the handheld optical refractometer using serum was 5.6 g/dL [sensitivity (Se) 70.1%; specificity (Sp) 80.0%; area under the curve (AUC) 0.85]. For centrifuged plasma, the optimal threshold was higher at 6.3 g/dL (Se 82.1%; Sp 68.1%; AUC 0.84), and for filtered plasma, the threshold was 6.0 g/dL (Se 56.7%; Sp 90.0%; AUC 0.80). The digital Brix refractometer (device 1: HI 96801) had the optimal threshold at 8.9% Brix using serum (Se 82.1%; Sp 63.8%; AUC 0.81), and at 9.4% Brix (Se 76.1%; Sp 73.7%; AUC 0.80) using centrifuged plasma, respectively. The device 2 (Misco PA201) determined the optimal threshold at 8.7% Brix (Se 74.6%; Sp 76.2%; AUC 0.83), 9.5% Brix (Se 80.6%; Sp 70.6%; AUC 0.83), and 9.2% Brix (Se 58.2%; Sp 87.5%; AUC 0.80) using serum, centrifuged plasma, and filtered plasma, respectively. All the three devices with the different media had comparable test characteristics to assess calves with FPT, based on the AUC determined with ROC curve analyses. Plasma samples (centrifuged and filtered plasma) revealed higher optimal thresholds to assess FPT compared with serum. Furthermore, the three different devices had comparable AUC irrespective of the used medium (centrifuged serum, centrifuged plasma, or filtered plasma). The results demonstrate that a filter system is suitable as a point-of-care analysis for FPT assessment, but further research is necessary. The aim of the second study was to evaluate two different treatment procedures at first milking after calving to increase colostrum quantity and to improve colostrum quality in dairy cows. We assumed that exogenous treatment with oxytocin or the presence of the calf at harvesting the first colostrum would lead to higher colostrum quantity and higher IgG concentrations. For the study, a total of 567 dairy cows were enrolled. For the final analyses, only 521 animals were considered and 46 dairy cows were excluded due to several reasons, such as lameness, bloody or mastitic colostrum, gestation length of less than 265 d, twin births and missing data. Three groups were built in which the cows were randomly assigned on a daily basis: (1) control group (CON; n = 177), (2) application of 20 IU of oxytocin i.m. (OXY; n = 163), and (3) presence of the calf (CA; n = 181) before and during milking. The milking of the first colostrum took place in a separate milking parlor. Dairy cows in the control and oxytocin group had no contact with their calves after calving. Three minutes before manual stimulation, the cows in the oxytocin group were injected with 20 IU of oxytocin i.m. into the neck region. Cows in the CA group got their calf presented three minutes before milking, whereby the calf was placed into a calf cart and located in front of the cow. Colostrum quantity (kg) was recorded and colostrum quality was determined by Brix refractometry and ELISA. To evaluate the data a generalized linear mixed model (GENLINMIXED) was constructed using SPSS (SPSS Inc., IBM, Ehningen, Germany). The mean colostrum quantity was 4.17 ± 0.30 kg (means ± SE). The treatment procedures and the harvesting time after calving did not affect colostrum quantity, but parity, calf birth weight, and calving time had an influence on colostrum quantity. The lowest quantity of colostrum had cows in second parity (3.74 ± 0.37 kg). Whereas cows in parity 1 (4.75 ± 0.34 kg) and cows in parity 3 or greater (4.75 ± 0.38 kg) had higher colostrum quantities. Further, cows calving at night (22:00 until 06:00 h; 4.93 ± 0.37 kg) had the highest quantity of colostrum. Cows calving in the morning (06:00 until 14:00 h; 4.17 ± 0.38 kg) or afternoon (14:00 until 22:00 h; 4.14 ± 0.34 kg) had a reduced amount of colostrum. Forty-eight percent of the colostrum samples assessed by ELISA contained ≥ 50 mg IgG/mL (54.6 ± 2.80 mg IgG/mL). The treatment procedures had an effect on colostrum quality, as well as colostrum quantity, parity, calving time, harvesting time after calving, and the calving day during the week. The treatment procedures achieved on mean higher IgG concentrations in colostrum (OXY: 57.0 mg IgG/mL; CA: 56.0 mg IgG/mL) compared with the control group (50.7 mg IgG/mL). High colostrum quantity and a longer time lag between calving and milking decreased the colostrum quality. Cows in parity 3 or greater (64.6 ± 2.59 mg IgG/mL) had higher IgG concentrations compared with cows in parity 1 (48.5 ± 2.86 mg IgG/mL) and cows in parity 2 (50.7 ± 2.89 mg IgG/ mL). Calving at night resulted in greater IgG concentrations (60.4 ± 2.92 mg IgG/mL) compared to calving at the morning or afternoon time (51.9 ± 2.98 and 51.3 ± 2.71 mg IgG/mL). Calving on Sundays increased the colostrum quality (61.4 ± 3.70 mg IgG/mL). The treatment procedures and the harvesting time after calving had no effect on colostrum quality assessed by Brix refractometry. Nevertheless, a negative association was observed between colostrum quantity and quality as with ELISA testing. Cows in parity 3 or greater showed higher Brix readings (27.7 ± 0.26% Brix) compared with cows in parity 1 (25.3 ± 0.30% Brix) and cows in parity 2 (25.0 ± 0.32% Brix). The purpose of the third study was to evaluate different analytical methods [i.e., ELISA, capillary electrophoresis (CE), refractometry] and three different media (i.e., centrifuged serum, centrifuged plasma, filtered plasma) to assess FPT in neonatal calves. As gold standard, radial immunodiffusion (RID) was chosen, and as before, FPT was defined by serum IgG concentrations < 10 mg/mL. Blood samples were collected from Holstein Friesian calves (n = 216) aged 1 to 7 days, from two commercial dairy herds in Northeast Germany. Serum was gained through centrifugation, and plasma extraction was performed either through a filter system or through centrifugation, as in the first study. For plasma filtration a disposable plasma filter was used (2-Drop-Filter, Pharmadoc, Lübeck, Germany). The laboratory methods, RID, ELISA, and CE, determined the IgG concentration in serum samples. For refractometry, two refractometers were used, a handheld optical refractometer (RF.5612 Handheld refractometer, Euromex Holland, Arnhem, Netherlands), assessing the TP concentration in all three media, and a digital Brix refractometer (Misco PA201, Misco, Solon, OH), assessing the TS, respectively. The RID analysis showed a prevalence of FPT of 27% (59/216) and 73% (157/216) with successful passive transfer. The Pearson correlation coefficient between RID and CE in serum was r = 0.97, and between RID and ELISA, it was r = 0.90, respectively. In addition, a high correlation between CE and ELISA could be identified (r = 0.89). Refractometry results were highly correlated with RID using either centrifuged serum, centrifuged plasma, or filtered plasma (Brix refractometer: r = 0.84; r = 0.80; r = 0.78; handheld optical refractometer: r = 0.83; r = 0.81; r = 0.80). The test characteristics to identify calves with FPT (optimal thresholds, Se, Sp, positive predictive value [PPV], negative predictive value [NPV], and AUC) for all methods and the three different media were determined by ROC curve analyses by using RID as the reference value. In summary, all four different analytical methods were suitable to assess FPT (ELISA, CE, and two refractometry methods). The test accuracy within the direct laboratory methods and within the indirect on-farm devices was very good, as the 95% CI for AUC overlapped, regardless of the three different media (centrifuged serum and plasma, or filtered plasma). However, different cutoff values for each analytical method must be considered, in particular if different media were used. The results demonstrate again, as in the first study, that optimal thresholds using plasma were higher compared with serum. In conclusion, all methods can be used for the assessment of FPT, and serum and plasma samples can be used interchangeably if the different cutoff values are taken into consideration. Overall, this thesis shows that (1) a disposable plasma filter system is appropriate as a point-of-care system for FPT analysis, but further research is required, (2) exogenous oxytocin and the presence of the calf improve the IgG concentration in colostrum at the first milking, but do not have an influence on colostrum quantity, and (3) different analytical methods are suitable to assess FPT if different cutoff values are taken into account. These results have the potential to improve colostrum management and calf health on dairy farms.