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
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)
Objective—To evaluate several practice-adapted
assays for determination of passive transfer status in
Animals—24 llama and 9 alpaca crias.
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
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