THE EFFECT OF PYROMELLITIC DIIMIDE UPON THE RUMEN FERMENTATION OF SHEEP FED A FORAGE DIET

Pyromellitic diimide (PMDI) was added at the rate of 0, 50, 100, 200 and 400 mg kg-1 DM day-1 to a diet of chaffed lucerne hay fed to groups of three sheep at hourly intervals. PMDI addition had no effect upon apparent digestibility, or upon the rate of degradation or potential degradability of DM in the rumen. The rumen acetate: propionate ratio was substantially lowered by PMDI, with the minimum effective concentration being 100 mg kg-1 DM day-1. Protozoa numbers per ml rumen fluid increased at this concentration, but decreased at the higher dietary PMDI concentrations. The rumen ammonia concentration linearly decreased with increasing dietary PMDI concentration. It was concluded that PMDI was an effective rumen fermentation modifier for sheep fed a dried forage diet, and should be further evaluated with sheep fed fresh perennial ryegrass/white clover pasture grown in the autumn/winter period. © 1990.