Impact of sulfur levels and sources for goats

Scope and method of study. The purposes of this study were to determine the dietary requirement for sulfur (S) by young and adult Angora goats, to determine if supplemental methionine in drinking water will increase the post-ruminal supply of methionine and enhance mohair growth, and to determine if S deficiency alters the amino acid composition of ruminal bacteria. A total of 87 goats were used in these studies. Goats received supplemental dietary S either as sodium sulfate or as DL-methionine in the drinking water or in feed. Sulfur adequacy was assessed by measuring mohair production, feed intake, plasma amino acids, bacterial S-amino acid concentrations, and ruminal parameters. Effects of supplemental S were evaluated at two different stages of growth (growing or adult Angora goats). Effects of supplemental S on ruminal bacteria was assessed with two different goat breeds (Angora and Alpine).;Findings and conclusions. When S was below.15% of dietary dry matter, mohair production was increased dramatically when S was supplemented in either the inorganic (sulfate) or the organic (methionine) form. Based on plasma methionine responses, a substantial proportion of supplemental methionine either in water or feed escaped ruminal destruction. For maximum mohair production, the optimal dietary S concentration was.18% for adults and.26% for young goats. As dietary S concentration was increased from.18 to.26% of diet dry matter, bacterial cystine concentration was not constant but increased indicating that specific deficiencies can alter amino acid composition of the mixed population of bacteria in the rumen. No mohair response to supplemental methionine was detected when dietary S exceeded.26%. Results can be interpreted to suggest that although S-amino acid supply can limit production of mohair, most if not all of this need for S-amino acids can be met by bacterial synthesis in the rumen provided an adequate amount of S is available from the diet.