Mineral Metabolism and Skeletal Development of Lambs Affected by Trichostrongylus colubriformis

The effects of an injection of Trichostrongylus colubriformis on skeletal development and utilization of calcium, phosphorus and magnesium in growing lambs has been examined in 2 experiments using animals initially reared free of gut parasites. In experiment 1, 18 lambs each infected with 40,000 larvae were compared with 6 uninfected control animals. Eight of the infected lambs, whose growth was severely retarded, showed a poor utilization of phosphorus which was apparent 3 weeks after infection and subsequently became more pronounced. The utilization of dietary calcium and magnesium was only slightly adversely affected. The interference with phosporus metabolism led to a severe lack of bone mineralization and certain bone deformities and abnormalities. Concentrations of serum albumin and phosphorus were also depressed. In experiment 2, 16 out of 20 worm-free lambs were each infected with 40,000 larvae of T. colubriformis and 12 of these animals were given extra phosphorus or cholecalciferol or both nutrients. The results were inconclusive in confirming the importance of phosphorus deficiency in infected lambs and in showing that it may be obviated by increasing the amount of phosphorus supplied to the animal.