Effects of Dietary Sulfur Addition and Synovex-S Ear Implants on Feedlot Steers Fed an All-Concentrate Finishing Diet

Abstract

A series of three trials was conducted to study the effects of dietary sulfur addition and Synovex-S ear implants on feedlot steers fed an all-concentrate finishing diet. In trial 1, 48 beef steers were implanted with diethylstilbestrol (DES) and fed for 28 weeks an all-concentrate diet supplemented with either 0, 1.4, 4.2 or 9.8 g of sublimed sulfur per kilogram of diet. The 9.8 g-sulfur treatment was ended at 10 weeks because of low feed intakes and weight loss. Rate of gain was not different among treatments with 0, 1.4 and 4.2 g of sulfur, but feed:gain ratio was improved approximately 5.5% with both levels of sulfur supplementation. In trial 2, 48 beef steers and 16 dairy steers were fed for 28 weeks the same all-concentrate diet as in trial 1 supplemented with either 0 or 1.4 g of sulfur per kilogram of diet. The steers were stratified according to breed, and one-half of the steers in each breed-sulfur treatment group were implanted with Synovex-S implants. Among the implanted steers, sulfur supplementation improved the feed:gain ratio by 10%. Growth rate was 25% greater and feed:gain ratio was 11% less for Synovex-S implanted steers. Neither sulfur nor Synovex-S had consistent effects on carcass merit, ruminal pH, ammonia (NH₃), volatile fatty acids (VFA) and lactic acid, or on blood plasma NH₃, amino acids and lactic acid. In trial 3, eight ruminal fistulated beef steers in a replicated experiment were fed the same all-concentrate diet as in trial 1 supplemented with either 0, 1.4 or 4.2 g of sulfur per kilogram of diet. Steers were withheld from feed for 96 hr (restricted) and then refed as a means of causing ruminal lactic acid accumulation. Sulfur supplementation appeared to lower the peak accumulation of both D- and L+ lactic acid after feeding. Concurrent ruminal NH₃ and VFA data suggested a more optimal ruminal fermentation for the supplemental sulfur treatments; thus, part of the benefit from supplemental sulfur may be to reduce intermittent lactic acid accumulation in the rumen. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.