Effect of Methionine Supplementation Posterior to the Rumen on Nitrogen Utilization and Sulfur Balance of Steers on a High Roughage Ration

The effect of post ruminal methionine, dietary methionine or dietary sulfur (S) supplementation on nitrogen retention and S excretion was determined by using three Holstein steers fitted with abomasal cannula in a 3 × 3 Latin square design. The basal diet was fed ad libitum and consisted of ground timothy hay and concentrate in a 5:1 ratio. The diet contained 12% crude protein with urea contributing about 40% of the total nitrogen. Elemental S (0.05%) or methionine (0.22%) was added to the diet while a similar quantity of methionine was infused into the abomasum. Abomasal infused methionine compared with supplemental dietary S or methionine resulted in a 16.6 and 23.9% increase in percent of absorbed nitrogen retained, which was not statistically significant (probability approximately 0.25). Sulfur intake and apparent S digestibility was similar for all treatments; however, urinary S concentration tended to be lower for the elemental S treatment (probability approximately 0.10). Sulfur retention was higher (P < 0.05) with supplementary elemental S than when a similar amount of S was consumed or infused in the form of methionine.