EFFECT OF LOW-TEMPERATURE STORAGE ON THE HEMOLYTIC COMPLEMENT OF CATTLE AND SHEEP

Sera from cattle and sheep stored at -70, -20 and -10-degrees-C were e xamined for haemolytic complement at Days 0, 37, 54, 86, 133 and 245. The decline in complement followed a similar trend, both by classical pathway (CPW) and alternative pathway (APW) assay methods. Both cattle and sheep sera retained 80% of their complement activity till Day 245 at -70-degrees-C whereas at -20-degrees-C cattle sera had lost 67% an d sheep sera 80% of the activity. At -10-degrees-C the decline in comp lement levels was, in general, similar to -20-degrees-C. The complemen t level of sheep sera declined more rapidly than that of cattle. For r eliable results, it is suggested that sera of cattle and sheep should be assayed for complement within 4-5 months at -70-degrees-C and withi n a month at -20 or -10-degrees-C.