Effect of protected urea feeding on ciliated rumen protozoa population of lambs

Abstract

Twelve male Hampshire Down lambs, average weight 29,37 kg (3,89 kg) and 6 months old, were used in a trial with 4 handlings, using Andropogon grass hay, soy meal and (GPS) at different rates. 18 g of protected urea were added to handlings B and C. Protein levels were given at 100% of NRC requirements (A and B rations) and at 70% (C and D rations). Ruminal fluid samples were obtained at the last day of the trial, one hour after the feeding of animals. Urea stimulated the division of entodimomorphic ciliates (handlings B and C, p ≤ 0,01). Average values for ciliates were 49,54 and 39.02 x 10³ ml^-1 respectively for handlings with and without urea. Results show that included quantities of 18 g of protected urea failed to induce metabolic disorder in animals.