Feed analyses and mineral contents of lupins associated with lupinosis of sheep in Western Australia

Abstract

Lupin components from 25 experimental paddocks in the Gingin-Dandaragan area were analysed for standard feed components and trace elements in 1961 and 1962-63. Lupinosis had occurred in all the experimental paddocks. Much of this area is deficient in trace elements and lupinosis appeared in 1948 soon after copper-ore topdressing was introduced and the use of superphosphate greatly expanded. The analyses were related to soil types, past dressings of copper and zinc, and compared with general lupin analyses in the district. Protein and calcium in the leaf and seed and calcium to phosphorus ratios in the leaf were high. Cobalt was often below the critical range for sheep health, iron was very high (815-2400 p.p.m. in leaves), organic sulphate was low (mean 0.2 per cent) and manganese was high (mean 326 p.p.m. in leaves). Molybdenum varied widely and was related to past copper and zinc topdressing. It was high in lupin seed where copper-ore topdressings were applied. Copper was marginal for sheep health (3-6 p.p.m.) in leaf and seed and deficient in stems and in associated grasses. Copper was lower and molybdenum higher on paddocks where lupinosis was severe.