Ostertagia infection and neutrophil function in cobalt-deficient and cobalt-supplemented cattle

Young cattle maintained on cobalt-deficient diets had significantly impaired neutrophil function as compared with cobalt-supplemented controls. Experimental infection with Ostertagia ostertagi larvae in cobalt-deficient and cobalt-sufficient animals resulted in reduced liveweight gains in both groups. However, the prepatent period was shorter, worm egg output greater, and plasma pepsinogen levels lower in cobalt-deficient calves. The total worm burdens in all animals at slaughter were low but the possibility of impaired immunity to infection in cobalt-deficient cattle is discussed.