An evaluation of ammonium sulphate as a potential NPN source for ruminants

Abstract

Experiments were undertaken to examine the comparative toxicity to sheep of ammonium sulphate and urea given as single doses and the value of ammonium sulphate fed alone or in combination with urea as a supplement to low nitrogen roughages. Ammonium sulphate dosing produced significantly lower mean blood ammonia levels than urea dosing. Fifteen grams of nitrogen as ammonium sulphate were tolerated as a single dose but the equivalent level of urea was toxic. lnappetance and ruminal stasis was noted when sheep fed a low nitrogen roughage (0.5 per cent nitrogen) received ammonium sulphate supplement as the sole non-protein nitrogen source. Ruminal stasis and inappetance may have been due to sulphide toxicity. Ammonium sulphate when used at lower levels in varying combinations with urea was well utilized as a nitrogen and sulphur source even when supplying 50 per cent of the supplemented nitrogen.

Studies on the sulfur metabolism of cows on protein-free and low-protein feed

“…A fairly large sulfate content in their feed may have caused too rapid a generation of sulfide in relation to its utilization for protein synthesis by the rumen microbes. Observations that the supplementation of feeds with sulfates can produce a depression in feed intake in cows and sheep (Elam 1975, Graham et al 1976 Puhdasrehun, jossa proteiini oli korvattu urealla ja ammoniumsuoloilla (0-rehu), sekä puhdistamattoman, runsaasti ureaa ja vähän proteiinia sisältävän rehun (ULP-rehu) vaikutusta lehmien rikkiaineenvaihduntaan on tutkittu määrittämällä eri rikkifraktioiden pitoisuuksia lannoista, virtsoista, maidoista, veristä ja pötsinesteistä. 0-rehussa rikki oli yksinomaan epäorgaani-sina sulfaatteina.…”