Effect of molasses supplementation and copper, cobalt and anthelmintic therapy on weight gain of beef yearling steers grazing improved pastures in a wet tropical environment

Abstract

The effects of copper, cobalt and anthelmintic therapy on weight gain and serum copper values were measured in 240 Brahman cross yearling steers half of which were supplemented with a molasses, meat meal, urea, monoammonium phosphate mixture. Cattle grazed fertilized grass-legume pasture in a wet tropical area of north Queensland. Similar weight gains were observed in the non-supplemented groups treated with copper and cobalt as in the non-treated control group. In groups that received the molasses supplement, those treated with copper and cobalt gained significantly more weight than the non-treated control group. There was also a highly significant interaction between treatments with both copper and cobalt and supplementation. Supplementation did not reduce the effect of nematode parasitism on weight gain. Supplemented animals treated each three weeks with levamisole had a 10.2 kg greater weight gain response over the 132 days treatment period than similarly treated non-supplemented animals. Supplemented animals grew faster than non-supplemented animals only during the cool dry late winter and early spring corresponding to the period when pasture quality and availability were lowest. Serum copper values of all groups were within the range of values for healthy cattle.