Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 141 PRODUCTION FEEDING OF WEANER LAMBS C.H. DAVIS* A series of experiments was conducted to examine the use of grainbased diets for intensively feeding weaner lambs. The lambs had mean initial live weights of between 20 and 26 kg and the experiments terminated with final live weights of 32 to 36 kg. Diets were fed ad Zibitwn to groups of 8 to 117 lambs, either daily in troughs, or from a selffeeder placed in yards devoid of forage. All lambs could eat simultaneously from the troughs; the yards provided at least 2 m2 lamb? Initially, whole grain plus mineral additives were examined, because these diets could be easily fed with equipment generally available on wheat/sheep farms. Addition of 1.5 per cent sodium chloride increased liveweight gain by 44 per cent and there was no additional advantage of supplementing the wheat grain with sodium buffer salts (Saville et al. 1973). Wheat plus sodium chloride was then compared with a diet consisting of '7'4 per cent wheat, 6 per cent meat meal and 20 per cent hammermilled lucerne hay. #Liveweight gains from the grain/roughage diet were 2.2 times greater than from wheat plus sodium chloride. The optimum ratio of grain to roughage was determined by feeding lambs diets of various ratios, based on either sorghum or oats, and made iso-nitrogenous with meat meal. The highest rate of liveweight gain and food conversion efficiency was obtained with a concentrate-to-roughage ratio of between 70130 and 60140. It would be difficult and/or expensive for a'producer to prepare these diets, with the roughage and grain hammermilled and mixed with other components, without specialised machinery. The effect of grinding or dry rolling the wheat in a 70 concentrate/30 roughage diet was tested in an extensive experiment, involving 265 lambs; there was no advantage. This was confirmed in another experiment with whole or dry rolled maize, sorghum, oats, wheat and barley-based diets. Hay was presented separately from grain in two ways - as bales, in a hay rack, or milled, in a self-feeder. This was compared with 30 per cent hay milled and mixed with 70 per cent wheat and fed by self-feeder (File 1976). Lamb liveweight gain was similar, irrespective of the method of feeding hay, but the lambs spilt and wasted some hay in the racks, in this case 32 per cent. If this could be tolerated, it would be simpler to feed hay from racks. Unde r c ommercial condit 'ions a producer could expec t cro ssbred lambs of 25 t0 35 kg to gain 200 G day- 1 with a feed intake 0 f 12 00 g. FILE, G.C. (1976). Proc. Aust. Soc. Anim. Prod. 11 : 437. SAVILLE, D.G., DAVIS, C.H., WILLATS, H.G., and McENES, P. (1973). Aust. J. exp. Agric. Anim. Husb. 13 : 22. * Drought Research Unit, Veterinary Research Station, Glenfiel&.NSW 2167. 141,