Serum IgG Concentrations after Intravenous Serum Transfusion in a Randomized Clinical Trial in Dairy Calves with Inadequate Transfer of Colostral Immunoglobulins
Corresponding author: Dr M. Chigerwe, BVSc, MPH, PhD, DACVIM, Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, One Shields Avenue, Davis, CA 95616; e-mail: firstname.lastname@example.org.
Background: Plasma transfusions have been used clinically in the management of neonates with failure of passive transfer. No studies have evaluated the effect of IV serum transfusions on serum IgG concentrations in dairy calves with inadequate transfer of passive immunity.
Hypothesis: A commercially available serum product will increase serum immunoglobulin concentration in calves with inadequate transfer of colostral immunoglobulins.
Animals: Thirty-two Jersey and Jersey-Holstein cross calves with inadequate colostral transfer of immunoglobulins (serum total protein <5.0 g/L).
Methods: Thirty-two calves were randomly assigned to either control (n = 15) or treated (n = 17) groups. Treated calves received 0.5 L of a pooled serum product IV. Serum IgG concentrations before and after serum transfusion were determined by radial immunodiffusion.
Results: Serum protein concentrations increased from time 0 to 72 hours in both control and transfused calves and the difference was significant between the control and treatment groups (P < .001). Mean pre- and posttreatment serum IgG concentrations in control and transfused calves did not differ significantly. Median serum IgG concentrations decreased from 0 to 72 hours by 70 mg/dL in control calves and increased over the same time interval in transfused calves by 210 mg/dL. The difference was significant between groups (P < .001). The percentage of calves that had failure of immunoglobulin transfer 72 hours after serum transfusion was 82.4%.
Conclusions and Clinical Importance: Serum administration at the dosage reported did not provide adequate serum IgG concentrations in neonatal calves with inadequate transfer of colostral immunoglobulins.
Despite understanding of passive transfer of colostral immunoglobulins, 35–40% of dairy calves in the United States have inadequate passive transfer of colostral immunoglobulins.1,2 Calves with inadequate transfer of colostral immunoglobulins have increased risk of mortality in the 1st 12 weeks of life,2–4 decreased rate of weight gain,5 and lower milk production in the 1st lactation and increased culling in their 1st lactation.6
Plasma has been recommended empirically as a prophylactic intervention in calves with inadequate transfer of colostral immunoglobulins.7,8 Previous studies reported that plasma transfusion increased calves' serum total immunoglobulin's concentrations, but was not protective in colostrum-deprived calves.9 Selim et al10 compared the efficacy of J5 Escherichia coli hyperimmune plasma and control bovine plasma as immunotherapy in neonatal colostrum-fed calves and concluded that the J5 hyperimmune plasma was not superior to control plasma or to no intervention. In the study by Selim et al,10 the passive transfer status of the calves before transfusion was not determined.
The objective of this study was to evaluate the ability of a commercially available serum product to increase serum IgG concentration in dairy calves with inadequate transfer of colostral immunoglobulins. No published studies have described serum IgG concentrations in calves after IV serum transfusions. We hypothesized that a commercially available serum product would significantly increase serum immunoglobulin concentration (serum IgG concentration ≥1,000 mg/dL) in calves with inadequate transfer of colostral immunoglobulins.
Materials and Methods
Jersey and Jersey-Holstein cross, 2–5-day-old heifer calves were identified and enrolled during the months of February to May 2007 from a pasture-based dairy farm in southern Missouri. The research study was approved by the University of Missouri-Columbia Animal Care and Use Committee. Biweekly ambulatory visits were made to this farm by 1 of the authors (M.C.). Cows on the farm calved on pasture. Recently calved cows were milked twice daily and colostrum collection from cows was performed twice daily after the milking of cows with milk suitable for sale. Calves were assumed to have suckled colostrum from their dams while on pasture. Calves were picked up from the pasture twice a day. Thereafter, calves were identified with plastic ear tags, weighed, and housed in groups of 10. Only those calves subjectively deemed not to have suckled colostrum by calf-rearing personnel were fed 2 L of colostrum by oroesophageal tubing.
In conjunction with biweekly farm visits, serum was collected by jugular venipucture from all 2–5-day-old calves and serum protein concentration determined by refractometry.a Calves with serum protein concentrations <5.0 g/dL were deemed to have inadequate transfer of colostral immunoglobulins and were enrolled in the study.2 Calves were then randomly assigned (coin toss) to either a control group (not receiving serum transfusion) or treatment group (receiving serum transfusion). Sample collection, weighing of calves, assignment of calves to groups, serum total protein determination, IV serum administration, and 72 hours follow-up serum sample collection were performed by 1 of the authors (M.C.). Only heifer calves were included in the study. Calves with missing values were excluded from the study.
The serum productb was derived from healthy yearling cattle. The serum product used was evaluated for sterility by the manufacturer. Serum administration procedure was performed on the farm. Administration of 0.5 L (1 U) of the serum product as recommended by the manufacturer was performed via the jugular vein with an IV catheter. Infusion of the serum product was performed slowly (10 mL/kg/h) over the 1st 20 minutes. Monitoring for transfusion reactions included monitoring heart rate, respiratory rate, color of mucous membranes, and abnormal behavior. In the absence of an immediate transfusion reaction, the remainder of the serum was transfused over 30–40 minutes. In the presence of a serum transfusion reaction, transfusion was discontinued for 10 minutes and resumed at 5 mL/kg/h.
Serum was collected at 72 hours posttransfusion in the treatment and control groups. Serum was stored at −20°C until processing for serum IgG determinations. Serum IgG concentrations were measured by a radial immunodiffusion (RID) technique. RID plates to measure serum IgG concentration were be prepared by dissolving 1% agarosec in a sodium barbital bufferc containing 0.1% sodium azide.c Rabbit antibovine IgG (2%)c was added to the agarose solution. Eleven milliliters of the agarose solution was added to 10 cm Petri dishes. After the agarose solidified, 3 mm wells were cut in the agar. Serum samples were diluted 1 : 20 using barbital buffer and 5 μL of the diluted serum sample was inoculated in each well. The diameter of the zone of precipitation was recorded after 72 hours of incubation at 23°C. Sample IgG concentrations were determined by comparing the diameter of zones of precipitation with a standard curve generated using serial dilutions of a bovine IgG standard.c The regression equation generated in this manner accurately predicted inoculum IgG concentration (r2= 0.97). Bovine standard samples and study samples were analyzed on the RID plates prepared from the same reagents on the same day. After constructing the standard curve, diluted samples of the bovine standard were saved and analyzed again on every plate used for analyzing study samples to evaluate for RID plate-to-plate variation.
Descriptive statistics were calculated for serum IgG concentration, calf birth weight, and serum total protein concentration. Initially, calf age and weight at the time of enrollment in the study were compared between control and transfused calves using 1-way analysis of variance. The difference between each calf 's initial and posttransfusion serum protein and serum IgG concentrations was calculated. Thereafter, the difference in pre- and posttransfusion serum protein concentration was compared between groups using 1-way analysis of variance.d In those circumstances in which equality of variance or normality tests failed, the Kruskal-Wallis 1-way analysis of variance on ranks was performed.d In all statistical analysis, values of P < .05 were considered significant.
The serum IgG concentration of the serum product was 1,584 mg/dL. Assuming a plasma volume of 5%11 of calf body weight, mean calf weight of 34.4 kg, mean pretransfusion serum IgG concentration of 675 mg/dL, the anticipated increase in serum IgG concentration after transfusion with 0.5 L of the serum product was calculated as follows:
Thus, the mean anticipated serum IgG concentration after serum transfusion would be indicative of adequate transfer of immunoglobulins.
Initially, 38 calves were enrolled to the study. Six calves had missing calf birth weights and were excluded from the study. Of the enrolled 32 calves, 15 were controls and 17 calves received IV serum transfusions. Two calves had transfusion reactions characterized by increased respiratory and heart rate, shivering, and abnormal vocalization. Results of calf age and calf weight at enrollment in the study, serum total protein (pre- and posttreatment) concentration and serum IgG concentration (pre- and posttreatment) are summarized in Table 1. Mean ± SD of serum protein concentrations increased from time 0 to 72 hours in both control (0.38 ± 0.25 g/dL) and transfused calves (0.82 ± 0.35 g/dL) and the difference was significant between the groups (P < .001). Assuming a serum protein concentration of <5.2 g/dL12 is optimal for indicating adequate transfer of passive immunity, 11.8% (2/17) and 60% (9/15) of transfused and control calves had failure of passive immunity at 72 hours, respectively.
Table 1. Mean ± SD for different variables for control calves and calves transfused with serum.
|Calf age at enrollment (days)||3.3 ± 1.0a||3.6 ± 1.0a|
|Calf weight at enrollment (kg)||34.6 ± 7.92a||34.4 ± 7.54a|
|Mean pretreatment serum total protein (g/L)||4.72 ± 0.16a||4.65 ± 0.26a|
|Mean posttreatment serum total protein (g/L)||5.10 ± 0.27a||5.47 ± 0.27b|
|Mean pretreatment serum IgG concentration (mg/dL)||845 ± 375a||675 ± 476a|
|Mean posttreatment serum IgG concentration (mg/dL)||774 ± 361a||740 ± 386a|
The difference between time 0 and 72 hours serum IgG concentration was not normally distributed. Median serum IgG concentrations decreased from 0 to 72 hours by 70 mg/dL in control calves and increased over the same time interval in transfused calves by 210 mg/dL. The difference was significant between the groups (P < .001). Assuming a serum IgG concentration of < 1,000 mg/dL13 indicates failure of passive transfer of colostral immunoglobulins, 82.4% (14/17) and 73.3% (11/15) of transfused and control calves had failure of immunoglobulin transfer at 72 hours, respectively.
The proportion of calves with failure of immunoglobulin transfer after serum transfusion still was significantly high after transfusion. Mean serum IgG concentration after transfusion was lower than the anticipated concentration. Results of this study show that 0.5 L of the serum product administered IV to relatively small Jersey and Jersey cross calves (mean weight, 34.4 kg) increased serum IgG concentrations, but the increase was insufficient to achieve adequate transfer of immunoglobulins. Several reasons are possible for failure of the serum product to significantly increase serum IgG concentration (serum IgG concentration ≥1,000 mg/dL). The volume or IgG concentration of the administered serum may have been insufficient. Half life of maternal colostral immunoglobulins is 20 days in calves.14 Although unknown, the half life of immunoglobulins administered in serum may be shorter than IgG acquired by ingestion of colostrum. Immunoglobulin concentration in control calves decreased significantly after 72 hours, suggesting catabolism and or resecretion of colostral maternal immunoglobulins. Reported plasma volume estimates in calves vary.11,15,16 The anticipated increase in serum IgG concentration after transfusion is affected by the estimate of plasma volume utilized. For example, using a 9% plasma volume estimate, the anticipated serum immunoglobulin concentration would be 930 mg/dL, which is indicative of failure of passive immunity. Thus, at plasma estimates of 9%, 1 U of serum as recommended by the manufacturer is not sufficient to achieve adequate passive immunity. Although the anticipated serum IgG concentration would be indicative of passive immunity using 5% as the plasma volume estimate in this study, the results indicate that serum administered at the recommended dosage by the manufacturer is insufficient to achieve adequate passive immunity.
Although IV serum transfusion for calves with failure of transfer of colostral immunoglobulins can be performed in clinical settings, the procedure is less likely to be performed by producers because of expertise, equipment, and monitoring required. Only 0.5 L of the serum product was used in this study based on the anticipated increase in serum IgG concentration and cost of the product. The results presented here only evaluated the ability of the serum product to increase serum IgG concentrations. To the authors' knowledge, no studies have evaluated the effect of IV serum administration on morbidity and mortality in dairy calves with inadequate passive transfer of colostral immunoglobulins. Morbidity and mortality in this group of calves could not be evaluated because of lack of follow-up (ie, the farm contracted rearing of the calves to different farms). A study evaluating the serum product in decreasing morbidity and mortality when sufficient volume of serum has been transfused in calves with inadequate transfer of colostral immunoglobulins is required. Only serum immunoglobulin G concentration was evaluated in the serum product and calves. Evaluation of other immunoglobulin classes (IgM and IgA) in the serum product and in calves should be considered in future studies. The concentrations of IgM and IgA in calf serum after transfusion with the serum product is anticipated to be higher compared with calves fed colostrum. The predominant immunoglobulin (85–95%) in colostrum is IgG whereas IgM and IgA constitute 7 and 3%, respectively.17 Thus, the total serum immunoglobulin concentration after serum transfusion would be higher than reported in this study. For additional studies, we recommend transfusion of a minimum of 2–3 U (1–1.5 L) of the serum product depending on calf size, followed by evaluation of morbidity and mortality in control and transfused groups.
aTS Meter, Leica, Buffalo, NY
bColorado Serum Company, Denver, CO
cSigma Chemical Co, St Louis, MO
dSigma Stat 2.03, Ashburn, VA
This research was supported in part by the American College of Veterinary Internal Medicine Foundation Grant and the University of Missouri Agricultural Experiment. Station. The authors thank Kevin Vanderpoel and Lynda Bean for their technical assistance.