Passive transfer of colostral immunoglobulin G in neonatal Ilamas and alpacas

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 conce ntrations 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 collecte d 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 se rum IgG concentrations for day-1, -2, and -3 samples for llamas were 1,578 mg/dl, 1,579 mg/dl, and 7,401 mg/dl, respectively, and for alpacas were 2,0 24 mg/dl, 1,806 mg/dl, and 1,669 mg/dl, respectively. Peak serum immunoglob ulin concentration developed between days 1 and 2. Mean half-life of IgG fo r all crias was 15.7 days. Conclusions and Clinical Relevance-Although increased mortality has been li nked to failure of passive transfer, it is clearly possible to raise crias that have low serum immunoglobulin concentrations. Llamas and alpacas do no t differ significantly with respect to immunoglobulin absorption or IgG con centration in neonates. The optimal sampling time for passive transfer stat us is between 1 and 2 days.