Sulfur metabolism in ruminants. II. In vivo availability of various chemical forms of sulfur.

Lambs fed semipurified diets supplemented with DL-methionine, hydroxy analog of methionine, calcium sulfate, sodium sulfate or elemental sulfur gained faster, consumed more dry matter, and digested and retained greater weights of nitrogen and sulfur (P<.01) than lambs fed a sulfur deficient diet. Lambs fed a sulfur deficient diet had severe weight losses in 40 days and were removed from the experiment. Lambs fed hydroxy analog of methionine had more (P<.05) wool growth than lambs fed elemental sulfur (33.2 vs 27.1 mm). Apparent dry matter digestibilities ranged from 76.1 to 80.9% for the various treatments. When expressed as a percent of intake, apparent nitrogen digestibilities were not affected by sulfur treatments, however lambs fed sulfur from each of the supplemental sulfur sources retained higher percentages (P<.01) of the nitrogen consumed than control lambs. Sulfur supplementat ion also improved the utilization of digested nitrogen. With the exception of lambs fed elemental sulfur, those fed sulfur from each of the sulfur sources digested greater percentages (P<.01) of their dietary sulfur than lambs fed a diet with no added sulfur. However, the lambs fed elemental sulfur retained a higher (P<.01) percent of digested sulfur than those fed the other sulfur sources. Sulfur retentions of lambs supplemented with sulfur varied from 48.5 to 61.8% during the initial 20 days of feeding, but varied from 31.5 to 39.4% during the third 20-day period. The reduced variation among lambs fed the various sulfur sources and the decline in percentages of sulfur that were retained suggests that body saturation with sulfur may have occurred after the initial 20 days. (