Authors : David E Anderson and Fernando Silviera
Abstract: To determine the variation of serum thyroid hormone concentration with age and gender for alpacas. 59 randomly selected alpacas. Alpacas were selected randomly and gender and age recorded. Age groups included < 6 months, 6 months to 2 years, 2 to 8 years, and > 8 years. Jugular venous blood samples were collected from all alpacas and serum separated. Serum samples were analyzed for thyroid hormone concentration including total T4, total T3, free T4, and free T3 by radioimmunoassay technique. Total T4 and T3 varied with age and gender. Females < 6 months old had significantly greater TT4 than all other groups. Females < 6 months old had significantly higher TT3 than all other groups. Males < 6 months old had significantly lower TT3 concentration than females < 6 months old, but greater than females > 6 months old. Free T4 and free T3 were similar among age and gender groups. Large variations in serum total thyroid hormone concentrations were reported for llamas and significant differences had been reported for gender but not for age. Concentrations of free T3 or T4 have not been published. This study showed an effect of age and gender on concentration of TT4 and TT3 but not FT4 or FT3 in alpacas. The 95 % confidence intervals provide an estimate of reference ranges for alpacas.
David E Anderson and Fernando Silviera , 2003. Effect of Age and Gender on Serum Concentration of Triiodothyronine and Tetraiodothyronine (Thyroxine) in Alpacas (Lama pacos) . Journal of Animal and Veterinary Advances, 2: 626-629.