Studies on High Intakes of Various Sulphate Salts and Sulphuric Acid in Sheep: 2. Effects on the Absorption, Excretion and Retention of Sulphur

Results are presented of a series of balance trials on sulphur in sheep which were fed pelletted grass meal alone or supplemented with either sodium sulphate, sodium bisulphate, ammonium bisulphate, ammonium sulphate or sulphuric acid, each in amounts equivalent to 1% sulphur in the feed dry matter. The diets were fed ad lib for 12 days and then at a constant restricted intake for 11 days. On the grass meal alone, which contained 0.45% sulphur, the amount of sulphur excreted in the urine was slightly higher than in the faeces. The faecal output of sulphur was related to the dry matter intake at about 0.22 g per 100 g feed. The absorption and excretion of sulphur were almost similar for the different supplements. Faecal excretion was not substantially increased by any of them except on the first 2 days, indicating that the additional sulphur was almost completely absorbed. The absorbed sulphur was very rapidly excreted mainly as sulphate-sulphur in the urine. There was a slight negative balance of sulphur on the control diet but a positive balance of 8 to 18% of intake on the supplemented diets. Urinary excretion of sulphur decreased to the same level as on the control diet within 2 days of withdrawal of the supplements.