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Evaluation of assays for determination of passive transfer status in neonatal llamas and alpacas

Dusty M. Weaver DVM, MS1, Jeff W. Tyler DVM, PhD, DACVIM2, Richard S. Marion DVM, MS3,4, Laurie M. Wallace DVM, MS, DACVIM, DABVP5,6, Jesse K. Nagy DVM7,8, and Julie M. Holle9
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  • 1 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.
  • | 2 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.
  • | 3 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.
  • | 4 Present address: Callaway County Veterinary Hospital, 5040 County Rd 306, Fulton, MO 65251.
  • | 5 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.
  • | 6 Present address: 222 Calvin Dr, Columbia, MO 65201.
  • | 7 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.
  • | 8 Present address:Rolling Hills Veterinary Hospital, 210 S Keene St, Columbia, MO 65201.
  • | 9 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.

Abstract

Objective—To evaluate several practice-adapted assays for determination of passive transfer status in crias.

Animals—24 llama and 9 alpaca crias.

Design—Prospective study.

Procedure—Serum IgG concentration was measured by use of a radial immunodiffusion assay when crias were 45 to 51 hours old. Results were compared with serum γ-glutamyltransferase (GGT) activity, serum total protein, albumin, globulin, and total solids concentrations, and results of commercially available and traditional sodium sulfite turbidity (SST) tests.

Results—Mean (± SD) serum IgG concentration was 1,762 ± 1,153 mg/dl. On the basis of a threshold value of 1,000 mg of IgG/dl at 48 hours of age, 5 of 33 (15.15%) crias had failure of passive transfer. Serum total solids, protein, and globulin concentrations were significantly associated with serum IgG concentration, whereas serum GGT activity and serum albumin concentration were not. Serum IgG concentrations were significantly different among crias with negative, 2+, and 3+ scores on the traditional SST test. Serum IgG concentrations were not significantly different between crias with negative and 100 mg/dl scores or 100 and 300 mg/dl scores on the commercially available SST test. However, all other comparisons between crias with different scores revealed significant differences. Sensitivity and specificity ranged between 0 and 1, depending on the test and endpoint selected.

Conclusion and Clinical Relevance—The commercially available SST test and determination of serum total protein and globulin concentrations are suitable methods for assessing passive transfer status in llama and alpaca crias. (J Am Vet Med Assoc 2000;216:559–563)

Abstract

Objective—To evaluate several practice-adapted assays for determination of passive transfer status in crias.

Animals—24 llama and 9 alpaca crias.

Design—Prospective study.

Procedure—Serum IgG concentration was measured by use of a radial immunodiffusion assay when crias were 45 to 51 hours old. Results were compared with serum γ-glutamyltransferase (GGT) activity, serum total protein, albumin, globulin, and total solids concentrations, and results of commercially available and traditional sodium sulfite turbidity (SST) tests.

Results—Mean (± SD) serum IgG concentration was 1,762 ± 1,153 mg/dl. On the basis of a threshold value of 1,000 mg of IgG/dl at 48 hours of age, 5 of 33 (15.15%) crias had failure of passive transfer. Serum total solids, protein, and globulin concentrations were significantly associated with serum IgG concentration, whereas serum GGT activity and serum albumin concentration were not. Serum IgG concentrations were significantly different among crias with negative, 2+, and 3+ scores on the traditional SST test. Serum IgG concentrations were not significantly different between crias with negative and 100 mg/dl scores or 100 and 300 mg/dl scores on the commercially available SST test. However, all other comparisons between crias with different scores revealed significant differences. Sensitivity and specificity ranged between 0 and 1, depending on the test and endpoint selected.

Conclusion and Clinical Relevance—The commercially available SST test and determination of serum total protein and globulin concentrations are suitable methods for assessing passive transfer status in llama and alpaca crias. (J Am Vet Med Assoc 2000;216:559–563)