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with adequate and inadequate passive transfer of immunoglobulin G . Am J Vet Res 1993 ; 54 : 56 – 59 . 7 Rea DE Tyler JW Hancock DD , et al . Prediction of calf mortality by use of tests for passive
JE , Brooks TP . Immunoturbidimetric quantification of serum immunoglobulin G concentration in foals . Am J Vet Res 1990 ; 51 : 1211 – 1214 . 19. McCue PM . Evaluation of a turbidimetric immunoassay for measurement of plasma IgG
Shi J Zhou Y , et al. Detection of red blood cell-bound immunoglobulin G by flow cytometry and its application in the diagnosis of autoimmune hemolytic anemia . Int J Hematol 2001 ; 73 : 188 – 193 . 10.1007/BF02981936 16. Mangan KF Besa
A bsorption of maternal antibodies in neonatal calves is commonly evaluated by measuring immunoglobulin G (IgG) as it is the primary immunoglobulin in bovine colostrum. 1 Radial immunodiffusion assays (RID) are the reference test for measuring
Abstract
Objective—To evaluate precolostral hypogammaglobulinemia in neonatal llamas and alpacas, to determine when postcolostral peak serum IgG concentrations develop, to determine whether differences in postcolostral serum IgG concentrations between llamas and alpacas exist, and to determine postcolostral half-life of serum IgG in llamas and alpacas.
Design—Prospective observational study.
Animals—29 llama and 10 alpaca crias.
Procedure—Blood samples were collected prior to suckling and on days 1, 2, and 3 after parturition and analyzed for serum IgG concentration by use of a commercial radial immunodiffusion assay. Additional samples were collected on days 8, 13, and 18 from 8 crias to determine mean half-life of IgG.
Results—Llamas and alpacas are born severely hypogammaglobulinemic. Mean serum IgG concentrations for day-1, -2, and -3 samples for llamas were 1,578 mg/dl, 1,579 mg/dl, and 1,401 mg/dl, respectively, and for alpacas were 2,024 mg/dl, 1,806 mg/dl, and 1,669 mg/dl, respectively. Peak serum immunoglobulin concentration developed between days 1 and 2. Mean half-life of IgG for all crias was 15.7 days.
Conclusions and Clinical Relevance—Although increased mortality has been linked to failure of passive transfer, it is clearly possible to raise crias that have low serum immunoglobulin concentrations. Llamas and alpacas do not differ significantly with respect to immunoglobulin absorption or IgG concentration in neonates. The optimal sampling time for passive transfer status is between 1 and 2 days. (Am J Vet Res 2000;61:738–741)
Abstract
Objective—To determine the effects of dexamethasone on development of IgG subclass responses following vaccination of healthy horses.
Animals—11 mature Thoroughbreds.
Procedure—Horses received 2 IM injections at 2- week intervals of a vaccine containing inactivated infectious bovine rhinotracheitis, bovine viral diarrhea, and parainfluenza-3 viral antigens and were then randomly assigned to 2 groups. Six horses received dexamethasone (0.2 mg/kg of body weight, IM) twice weekly for 8 weeks starting the day of the first vaccination. Five control horses received an equivalent volume of saline (0.9% NaCl) solution. Antigen-specific serum IgG subclass titers were determined weekly after vaccination by use of an ELISA.
Results—Vaccination resulted in similar antigen-specific serum IgG(T) titers in dexamethasone-treated and control horses. In contrast, although control horses developed IgGa and IgGb responses after vaccination, corticosteroid administration completely inhibited these responses in treated horses.
Conclusions and Clinical Relevance—Cortico steroids can have profound effects on primary immune responses in horses and can significantly affect IgG responses to inactivated vaccines. Corticosteroid treatment regimens commonly used to treat diseases in horses may result induction of a nonprotective IgG subclass response, leaving treated horses susceptible to disease. Additionally, mechanisms regulating IgGa and IgGb responses appear to differ from those regulating IgG(T) responses. Further defining these mechanisms is a critical step in designing effective vaccines, and corticosteroid-induced immunomodulation may be a valuable tool for studying immune responses in horses. (Am J Vet Res 2000;61:1530–1533)
Abstract
Objective—To determine whether serum IgG concentrations in neonatal calves are adversely affected by short-term frozen storage of colostrum.
Design—Prospective study.
Sample Population—Experiment 1 consisted of 10 pairs of Holstein calves (n = 20) fed matched aliquots of either fresh (n = 10) or frozen and thawed (10) colostrum. In experiment 2, 26 Holstein calves were fed either fresh (n = 13) or frozen and thawed (n = 13) colostrum.
Procedure—Experiment 1 consisted of calves resulting from observed parturitions; calves were randomly assigned to treatment groups (fresh or frozen and thawed colostrum) in pairs. Calves were fed 4 L aliquots of colostrum via oroesophageal intubation at 3 hours of age. Serum IgG concentrations at 2 days of age were compared between the 2 groups by use of a paired t-test. Experiment 2 consisted of calves resulting from observed parturitions; calves were randomly assigned to treatment groups (fresh or frozen and thawed colostrum). Calves were fed 4 L aliquots of colostrum via oroesophageal intubation at 3 hours of age. Regression analysis was used to determine whether calf serum IgG concentration was a function of colostral IgG concentration and colostrum storage group.
Results—Significant differences were not observed between the 2 groups in experiment 1. No significant relationship was observed between colostrum storage group and serum IgG concentration in experiment 2. The model that best predicted serum IgG concentrations accounted for 20% of the variability in serum IgG concentration.
Conclusion and Clinical Relevance—Frozen colostrum is an adequate source of IgG for calves. (J Am Vet Med Assoc 2001;219:357–359)
Abstract
Objective—To determine the effects of intensive serial plasmapheresis on total plasma protein and total IgG concentrations in donor horses involved in a plasmapheresis program.
Animals—18 horses (13 mares and 5 geldings; 13 Belgians, 3 Percherons, 1 Standardbred, and 1 warmblood) ranging from 7 to 14 years of age (mean ± SD, 10 ± 3 years) and weighing 822 ± 128 kg.
Procedures—Horses from which 22 mL of plasma/kg of donor body weight was harvested at 14-day intervals for a minimum of 8 consecutive plasmapheresis donations were retrospectively selected for use in the evaluation. Automated plasmapheresis procedures were performed by use of 2 modified plasmapheresis instruments/donor horse. Plasma samples were obtained at each donation and used for determination of total protein and total IgG concentrations. Total plasma protein concentrations were determined via refractometry. A commercially available ELISA was used to determine total equine IgG concentrations.
Results—The 18 donor horses were used in 8 to 19 serial donations (mean ± SD, 13 ± 3 donations) during the study. Donor horses had significant decreases in both plasma protein and IgG concentrations over the study period.
Conclusions and Clinical Relevance—Serial plasmapheresis procedures caused significant decreases in both plasma protein and IgG concentrations in donor horses; however, decreases were not physiologically relevant. Performing plasmapheresis in horses in accordance with the evaluated automated plasmapheresis procedures did not result in a critical decrease in total plasma protein or total IgG concentrations.
1996 ; 79 : 886 – 889 . 10 Hopkins BA Quigley JD . Effects of method of colostrum feeding and colostrum supplementation on concentrations of immunoglobulin G in the serum of neonatal calves . J Dairy Sci 1997 ; 80 : 979 – 983 . 11
