Effect of temperature on the sodium sulphite precipitation test for assessment of goat serum immunoglobulin

Total serum immunoglobulin concentrations of apparently normal indigenous goats were estimated by a sodium sulphite precipitation test which utilized 3 concentrations of the salt (i.e. 14%, 16%, 18%). A total of 210 goat serum samples comprising five phenotypically different breeds were examined. Immunoglobulin precipitation was greatly influenced by the incubation temperature. Using different concentrations of the sodium sulphite salt solution, serum samples incubated at either 4°C or 38°C consistently gave clear and rapid precipitation reaction in all samples with immunoglobulin concentrations of over 15 mg/ml.

Tests carried out at normal tropical room temperature (28°–30°C) gave inconsistent results and only 52% gave clear precipitation. Neither breed nor sex had any statistically significant effect on either the precipitation rate or the immunoglobulin values (P < 0.05).

It was concluded that this test if performed at either 4°C or 38°C can be used under field conditions to evaluate immune status of neonatal goats in the tropics.