Doublecropped Temperate and Tropical Corn Silages for Growing Beef Steers

Abstract

Doublecropping corn (Zea mays L.) for silage will maximize forage production per acre in the Coastal Plain of the southeastern USA. The production and feeding value of doublecropped temperate and tropical corn hybrids were evaluated with growing beef steers. Temperate corn was harvested for silage on 20 July at 36.4% dry matter (DM) at 110 d after planting and the tropical corn at 23.8% DM on 11 November at 100 d after planting. The tropical corn produced 14% more DM/acre than did the temperate corn. Grain comprised 43.7% of the harvested DM in the temperate corn and 27.1% in the tropical corn. Ensiling fermentation characteristics of the two corn hybrids were typical of well-preserved silage. Tropical corn silage was 7.6% higher in crude protein (CP) but 20% lower in ether extract. Crude fiber, acid detergent fiber (ADF), and neutral detergent fiber (NDF) were 29%, 31%, and 20% greater, respectively, for tropical corn silage. Both silages were fed to 36 growing beef steer calves (average initial weight 500 Ib) during an 84-d feeding period. Apparent digestibilities of ADF, NDF, DM, and organic matter (OM) were all greater for the tropical corn silage diet. Total mean retention time of the particulate matter in the digestive tract was longer for steers fed the tropical corn silage. Steers fed the temperate corn silage diet consumed 16.9% more DM/d and gained 17.6% faster (P < 0.01) than steers fed tropical corn silage. However, DM required per unit of gain was similar for the two silage diets. Temperate and tropical corn hybrids can be successfully doublecropped and harvested for silage in the Coastal Plain of the USA to provide increased production per acre and promote expected animal body weight gains.