Effects of cottonseed meal and cereal grain supplements on intake and utilisation of alkali-treated wheat straw by cattle

Abstract

Effects of cottonseed meal and cereal grain supplements on intake and utilisation of alkali-treated wheat straw were studied with 45 Friesian heifers (250 kg liveweight) in individual pens. Responses were measured in terms of feed intake and growth rate over 60 days. The basal diet fed ad libitum was coarsely milled wheat straw which was alkali-treated, sprayed with a solution containing urea, sulfur, copper and cobalt and sprinkled with dicalcium phosphate. Animals were also fed 800 g/day of 1 of 5 supplements: cottonseed meal (CSM), whole barley (WB), cracked barley (CB), ammonia-treated whole barley (NB) and extruded barley (EB). Intakes of the basal diet did not differ significantly between groups. Digestible organic matter in dry matter (%) was 53.1, 51.7, 47.2, 47.7, and 48.7 with supplements CSM, CB, WB, NB and EB, respectively; values for CSM and CB were significantly higher than for the other supplements (P< 0.05). Liveweight gains were 891,761,639, 657 and 784 g/day with the respective supplements, and did not differ significantly between CSM, CB and EB. We concluded that CSM did not stimulate intake of roughage more than supplements of barley grain, and that growth of the cattle was limited primarily by intake of energy.