Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. I6 LUPIN GRAIN AS A SUPPLEMENT TO SHEEP GRAZING CEREAL STUBBLE J.B. ROWE* and J. FERGUSON SUMMARY Two experiments tested the use of lupin grain as a supplement for weaners grazing wheat stubble. The control groups in both trials received no supplement until liveweights dropped to 22 kg and then lupins were fed. In 1984 two lick-blocks were tested; the Rumevite 'Sheep and Cattle' block and the ICI 'Ultrapro 30' block. Liveweight changes of animals on the control (5 weeks), Rumevite block, ICI block (11 weeks) and lupin-fed (7 weeks) (200 q/head/d) t reatments were -40, -18, -8 and 40 q/d respectively. In the second experiment (1985) lupins were fed in three different ways to provide 150 q/head/d. These were: trailed twice weekly: trailed weekly; and spread throughout the paddock every four weeks. Liveweight was maintained throughout the trial with all treatments of 150 q/head/d. (Keywords: supplementary feeding, lupins, blocks, stubbles). INTRODUCTION The rainfall in the wheat/sheep areas of Western Australia is typically mediterranean with little or no rain expected over the 5 to 7 summer months. The main source of sheep feed during this period is cereal stubble. Initially the selective grazing of stubbles allows animals to utilise the spilt grain and leaf material which provides adequate nutrition for maintenance of weight in all classes of sheep (Purser 1983). After this initial stage supplementary feeding is required to prevent weight loss and mortality in weaners and may also be necessary for pregnant ewes. Traditionally cereal grain, or urea-based lick blocks have been widely used as a source of supplementary feed. Over the last five years the Western Australian production of lupins has increased from 55 to 553 thousand tonnes (M.L. Meaton pers. comm.). This makes it a major source of feed grain in this State. The objectives of the experiments of lupins as a source of supplementary effectiveness, cost and convenience of urea or protein in addition to a range reported here were to examine the use feed for weaners and to compare their feeding with lick-blocks which provide of minerals. MATERIALS AND METHODS Proc. Aust. Soc. Anim. Prod. Vol. 16 Experiment 2 (January to April 1985) Twelve paddocks (0.7 ha) were fenced off on an even section of wheat stubble on light sandy soil havinq yielded 1.6 t wheat/ha which had been grazed (8 ewes/ha) for 3 weeks post-harvest. Seven weaners were allocated to each paddock and treatments weze allocated at random (3 paddocks/treatment). There was a control treatment in which animals received no supplement and three treatments in which 150 q lupins/hd/d were fed out in different ways: trailed twice/week; trailed weekly; or spread over the paddock at 4 week intervals. The trial commenced 24 January and terminated 18 April. The control qroups received supplementary feed after 8 weeks and were qiven 250 q lupins/hd/d from 21 March to the end of the trial. This was fed weekly. General Animals were drenched aqainst internal parasites 3 weeks before the commencement of the experiments and were weiqhed weekly durinq the trial. Chanqes in liveweiqht were analysed by analysis of variance usinq paddock means on weeks 5 and 11 (1984) and weeks 4, 8 and 12 (1985). The amount of stubble on offer at the start and end of the trial was estimated by cuttinq 30 quadrats (0.3 m2) throuqhout the trial site. Samples of stubble were analysed for N and acid deterqent fibre. Where lupins were spread over the paddock the rate of consumption was measured through random samplinq (20 samples/paddock) with a quadrat on days 1, 4, 6, 8 and 15 after feedinq. Rainfall was recorded. RESULTS The liveweiqht chanqes of animals during the two trials are summarised in Figure 1 and Table 1. In both trials unsupplemented animals lost weiqht rapidly (-48 and -176 q/d in 1984, 1985 respectively) and qrew well when qiven lupins at the rate of 200 q/d (42 q/d) and 250 q/d (119 q/d) respectively. Supplementation with both the Rumevite and ICI blocks siqnificantly (P < 0.05) decreased liveweiqht loss but were not as effective as feedinq lupins (200 q/d) in improvinq enerqy balance. The intake of both blocks increased durinq the trial and was variable between weeks (mean coefficient of variance 39.2 and 70.2%) and between paddocks (46.4 and 28.0%) for ICI and Rumevite blocks respectively. The cost of the supplements were: ICI blocks 63.6b/kq feed: Rumevite blocks 46.7#/kq feed and lupins 15b/kq (i.e. lupins at $150/t). The price of lupins in 1985 was lOb/kq. In the 1985 trial there were no differences between the three ways of supplementinq the animals with 150 9 lupins/d and all reduced the rate of liveweiqht loss siqnificantly (P < 0.001). The sheep fed four weekly were siqnificantly (P < 0.05) liqhter than those fed weekly or twice/week at the end of the first four-week period but there were no differences between these groups by the eighth or twelfth weeks. The lupins spread over the paddocks for the sheep fed four-weekly (on 21/3/85) disappeared at a linear rate (2.94 kq/paddock/d, equivalent to 420 q/head/d) over the first eight days after feedinq. This rate decreased after day eiqht until day 15 when no more lupins were seen in the paddocks. In 1984 the quantity of stubble at the start of the trial (24 Feb.) was 3.98 t/ha (ADF 54%; N 0.35%) which was reduced to 1.60 t/ha (ADF 69%; N 0.26%) at the end of the trial. In 1985 3.26 t/ha dry matter (ADF 57%; N 0.34%) was on offer at January 24 compared with 1.34 t/ha (ADF 65%; N 0.29%) by the end of the trial. In neither year was there any rainfall in January. From February to April several showers resulted in a total of 47 mm in 1984 and 116 mm in 1985. Small quantities of qreen feed were seen for short periods followinq rain. 344 Proc. Aust. Soc. Anim. Prod. Vol. 16 Fig. 1. Liveweight changes with time of weaners grazing stubbles and given different supplements during trials in 1984 and 1985. 1984 trial: (0) control; (0) 200 g lupins/d; (A) ICI Ultra pro 30; (A Rumevite Sheep and Cattle Block. 1985 trial: (0) control; (0) 250 g lupins/d (fed weekly); (A) 150 g lupins/d (fed twice weekly); (A) 150 g lupins/d (fed weekly); (0) 150 g lupins/d (fed four-weekly). Bars show SED Table 1 Intake of supplements and liveweight change of weaners grazing cereal stubbles over summer 345 Proc. Aust. Soc. Anim. Prod. Vol. 16 DISCUSSION The 1984 trial indicated that lupin qrain was at least as effective and certainly more economical as a supplement than were two feed blocks, Rumevite 'Sheep and Cattle' and ICI 'Ultrapro 30' in decreasing the liveweiqht loss of weaners qrazinq cereal stubbles. The low labour inputs required for feedinq blocks compared with the standard practice of feedinq qrain twice weekly has been a major reason for farmers to use blocks. Lupins have more fibre and less starch than cereal grain and offer the potential of feedinq out larqer amounts . less frequently. The 1985 results indicate that although feedinq stock with lupins at intervals of four weeks produces a fluctuatinq liveweiqht the overall result is similar to that achieved with twice-weekly feedinq. It was also shown that weaners use lupins very efficiently even when scattered over a sandy paddock. The amount and pattern of rainfall in both years was typical for most of the sheep/wheat area of Western Australia. In order to compare the results of the two experiments a relationship between supplementary feed intake and liveweight chanqe was examined. In 1984 the liveweiqht chanqe of the block-fed animals was estimated by reqression over the 11 week period while those for the control and lupin-fed animals were measured in the same way over the first 5 and next 6 weeks respectively. In the 1985 experiment animals lost weight rapidly durinq the initial two weeks probably due to the introduction to experimental conditions and the change from pasture to stubble qrazinq. Liveweiqht change for all sheep given 150 q lupins/d was estimated by reqression from week 2 to week 12. Similarly liveweight chanqe of the control qroup was estimated between weeks 2 and 8 and of the weaners given 250 q lupins/d between weeks 8 and 12. There was a good relationship (R2 = 0.86) between intake of supplement (lupins or feed block)(X, q/d) and liveweiqht chanqe of weaners grazing stubbles (Y, q/d) qiven by the equation: Y = -62 + 0.56X. This indicates that both types of supplements studied were used by the animals with similar efficiency (1.8 9 supplement/q liveweight change). In both trials the final liveweiqht of all treatment groups was similar irrespective of how this was reached. The most economical way to achieve this end liveweight is to allow the animals to lose weight before feedinq an above-maintenance level of supplement for a relatively short period towards the end of summer. The danqers with this strateqy are that there may be severe sheep losses if rain falls when the animals are in poor condition and secondly wool qrowth and quality may decrease with the low plane of nutrition. Supplementary feeding programmes are therefore in part an insurance policy but also require an assessment of the increased value of production which may arise from improved nutrition. ACKNOWLEDGEMENTS The skilled and meticu lous technica 1 assistance of Messrs R.S. Seaward, B.J. Guer in and P J. Murray is q ratefully acknowledqed. REFERENCES PURSER, D.B. (1983). In 'Stubble Utilization'. Counci 1: W.A.) (Rural and Allied Industries 346