Autumn grazing of finishing lambs on annual lupine (Lupinus angustifolius) under subarctic conditions
|Ólafur Guđmundsson, Sveinn Runólfsson||Búnađarfélag Íslands, Bćndaskólinn á Hvanneyri, Rannsóknastofnun landbúnađarins, Rannsóknastöđ Skógrćktar ríkisins, Tilraunastöđ háskólans í meinafrćđi, Veiđimálastofnun||1988||Reykjavík|
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The use of annual lupine was first studied in Iceland around 1900. However, due to a high content of alkaloids it was not suitable for animal feeding. A research program to test the suitability of annual lupines for Icelandic conditions was reinstituted in 1979. The trials indicated a great potential for annual lupines in Iceland as animal feed despite low summer temperatures. Further research with '°N has substantiated the ability of Rhizobium strains to function under these conditions. Lupinus angustifolius cv. Uniharvest from West Germany, which was the best commercially available variety of the 12 tested, was selected for two grazing trials. The lupine was seeded in May. The weather conditions during May through September were exceptionally cold in both years (8.6 and 8.4 °C with a ten year average of 9.0 °C), whereas the precipitation was 87 mm below the ten year average of 456 mm in the first year and 275 mm above average in the second year. Twin lambs of the Iceland breed were grazed on the lupine for 4 to 5 weeks in the fall. Control groups were grazed on kale and barley/ryegrass aftermath (experiment I) and on fertilized hayfield aftermath (experiment II) for the same period. The lambs in expt. I were 107 days old and weighed 31.6 kg and in expt. 11 115 days old and weighed 38.0 kg at the initiation of the trials. The lambs had been grazed on aftermath for two weeks prior to the experiments. Blood samples were collected at the beginning and the end of each trial. Higher hematocrit and lower urea levels were found in samples from lambs on the lupine than from the control lambs in expt. I. Urea, phosphorus and magnesium were higher and MCHC and glucose lower in samples from lambs on the lupine in expt. II. Lamb gains in all groups were excellent. During expt. I the lambs on both treatments gained over 450 g per day. In expt. II the lambs on lupine made less gain the first two weeks, needing some time for adjustment, but between 27 September and 14 October lambs on the lupine gained on the average 412 g per day compared to 167 g per day on the aftermath. The results indicate that lupine can play an important role in extending the period of rapid lamb growth late into the autumn.
Key words: Lupine, subarctic, grazing, growth, lambs, blood.
Haustbeit lamba á einćra fóđurlúpínu (Lupinus angustifolius) viđ íslenskar ađstćđur
Fyrstu rannsóknir međ einćra lúpínu voru gerđar hér á landi nálćgt síđustu aldamótum. Hátt innihald af alkalóíđum gerđi ţćr ónothćfar handa búfé. Ţetta, ásamt auknu frambođi af tilbúnum áburđi um miđbik aldarinnar gerđi ţađ ađ verkum ađ tilraunum var hćtt međ einćra lúpínu. Tilraunir međ mismunandi stofna af svo til alkalóíđlausum (sćtum) lúpínum, voru hafnar aftur áriđ 1979. Ţrátt fyrir lágan sumarhita á ţessum árum lofuđu niđurstöđurnar góđu. Frekari rannsóknir međ 15N hafa leitt í ljós töluverđa starfsemi rótarbaktería viđ hérlendar ađstćđur.
Af ţeim 12 stofnum sem prófađir voru, reyndist afbrigđiđ Uniharvest (Lupinus angustifolius) frá Vestur-Ţýskalandi best af ţeim tegundum sem fáanlegar voru á almennum markađi. Ţađ var ţví valiđ í ţćr haustbeitartilraunir sem hér er skýrt frá. Tilraunirnar voru gerđar tvö haust. Lúpínunni var sáđ í maí. Sumrin frá maí fram í september, voru bćđi mjög köld ( 8,6 °C og 8,4 °C). Úrkoma á sama tíma fyrra sumariđ, var 369 mm, en 731 mm ţađ seinna.
Lömbunum var beitt á lúpínu í 4 til 5 vikur. Samanburđarhópum, međ sambćrilegum lömbum, var beitt á kál og há af blöndu af byggi og rýgresi fyrra áriđ (1. tilraun) og á áborna há seinna áriđ (2. tilraun). Lömbin í fyrri tilrauninni voru ađ međaltali 107 daga gömul viđ upphaf tilraunarinnar og vógu 31,6 kg á fćti.
Lömbin í seinni tilrauninni voru aftur á móti 115 daga gömul og vógu 38,0 kg á fćti í upphafi. Lömbin höfđu veriđ á há í um ţađ bil tvćr vikur áđur en ţau voru sett í tilraunina.
Blóđsýni voru tekin viđ upphaf og lok tilraunanna. Hematókrít var hćrra og ţvagefni lćgra í sýnum lamba á lúpínunni í fyrri tilrauninni heldur en hjá samanburđarlömbunum. Hćrra ţvagefni, fosfór og magníum ásamt lćgra innihaldi af MCHC og glúkósa var í blóđi lamba á lúpínunni heldur en á hánni í seinni tilrauninni.
Öll lömbin ţrifust mjög vel. Bćđi lömbin á lúpínunni og samanburđarlömbin ţyngdust yfir 450 g á dag í fyrri tilrauninni.
Lupine research was initiated in Iceland around 1900 (Helgason, 1902). In the following years several studies were conducted on the cultivation of lupines (Jónsson, 1939). With increased availability of artifical fertilizers and also probably due to a high content of alkaloids in the cultivars tried, the interest in lupine declined and by the middle of the century the research had ceased.
In 1945 a perennial lupine, Lupinus nootkatensis, that originated in Alaska was established in Iceland (Einarsson, 1981), though it had been tried as early as 1910 (Helgason, 1911). This lupine is a very hardy species, producing a great amount of biomass during the summer. Unfortunately it is unsuitable as animal feed because of its high alkaloid content (Arnalds and Guđmundsson, 1980). However, its high rate of production created interest in trying other varieties of lupine, especially the sweet cultivars developed originally in Germany around 1930. These varieties have spread to various countries of the world and are now especially popular in Australia, Poland and the USSR (Williams, 1984).
In 1979 a research program was initiated. Twelve cultivars of two varieties were tested, with the intention of selecting the most productive one for use as autumn green feed for fattening livestock and for milk production. Two of the best cultivars turned out to be Lupinus luteus cv. Ventus from Poland and Lupinus angustifolius cv.
Uniharvest from West Germany (Arnalds and Bjarnason, 1981) but only the latter was commercially available at the time. Uniharvest was therefore selected for further research on autumn grazing of lambs.