and PCV values were found in goats without an apparent parasitic infection, an occasional and a 21 degree of parasitic infection. Lower mean serum Cu concentrations were found in sheep without evidence of parasitic infections and in goats with both 11 and 41 degree of mixed infections. Twenty-five to 37% of parasitized sheep and goats had serum Cu (,0.5 mg L 21) and P (,40 mg L 21) Below Critical Levels (BCL). Conclusions The degree of mixed parasitic infections was somewhat related to the lowered Hb and PCV mean values and serum Cu concentrations more so in goats than in sheep from swayback prone farms. Both regular treatment for parasitism and mineral supplementation would impact positively on the growth, health and productivity of sheep and goats of Central Trinidad.