Abstract:
4A THE EFFECT OF GRAIN FEEDING ON GROWTH RATES AND CARCASE ATTRIBUTES OF GRAZING STEERS IN CENTRAL QUEENSLAND M. JEFFERY*, T. JAMES*, I. LOXTON** In order to take advantage of the increasing demand for beef from developing Asian markets, Australian beef producers need to increase both the number and proportion of carcases meeting specific market requirements. The Japanese and Korean markets have specific requirements for carcase weight, carcase fat depth, dentition and carcase fat colour, with these requirements expected to become even more stringent. In many finishing areas of Queensland, up to 30% of animals fail to meet target liveweights for premium markets by winter. Producers are then faced with the decision of holding these animals longer on pasture, in some cases up to 12 months, selling them in an unfinished condition, or increasing nutritional inputs to overcome pasture quality deficiencies caused by frosts or dry conditions. In this experiment, the effects of feeding a grain ration on growth and carcase attributes were studied in grazing steers that were unsuitable for the Korean grass-fed market by winter. Feeding a grain ration to steers grazing frosted sown grass pastures decreased the time required for animals to reach liveweights suitable for the Korean market, compared to steers grazing pastures only. Carcase weights of the P - Turnoff 1 group were lower than desired because of delays at slaughter. Average daily gains were increased by up to OSkg/hd/day due to grain feeding. Rump fat depth increased with carcase weight in the P treatment as expected, but not in the P+G treatment. All treatment steers achieved the required minimum fat depth (7mm), however seven % of I steers had insufficient (<7mm) fat depth to meet Korean market specifications. Short term grain f&ing had no influence on subcutaneous rump fat depth. Feeding grain to steers in the paddock for 60 days failed to improt.*: (whiten) intermuscular fat colour, however feeding for an additional 28 days improved intermuscular fat colour. There was little difference in the proportion of AUSMEAT intermuscular fat colour scores < 5 betwen I and P - Turnoff 1 and P - Turnoff 2 and P+G at Turnoff 1, however, P+ G had noticeably more carcases (79%) with fat scores <5 at 88 days (Turnoff 2). This experiment has shown that ftzding a grain ration to steers entering the winter period when pasture quality declines, will increase growth rates and decrease the time required to ensure market suitability. Extended periods of grain feeding may also improve (whiten) intermuscular fat colour. The financial support of the Meat Research Corporation and the assistance of Queensland Department of Primary Hndustries staff is gratefully acknowltiged. rlr ++ Queensland Dcpartrnznt of Primary Industries, Brigalow Rexarch Station, M .S. 586, Tht=edort= Q 4719. Quztmsland Departnxnt of Primary Intlustrks, PO Box 6014, Rockhampton Q 4700.
