Effects of urea and sulfur on performance of faunate and defaunate Ramlic lambs, and some rumen and blood parameters

This study was conducted to investigate effects of defaunation, and addition of urea and sulfur, in replacement of plant protein (PP) sources on levels of some blood and rumen parameters, and body weight (BW) gain in lambs. Forty male ramlic lambs, 2.70±0.30 months of age, and weighing approximately 16.44±0.41 kg were used. Lambs were divided into four groups as: faunate+control diet (FC); defaunate+control diet (DC); faunate+experimental diet (FE); and defaunate+experimental diet (DE). The control diet contained plant protein as a N source, whereas the experimental diet was supplemented with urea and sulfur, both at 3% of BW per day. The forage portion of the diet was 350 g of alfalfa hay per lamb per day. Diets were fed twice daily in equal amounts. Defaunation, or feeding a diet supplemented with urea and sulfur in place of plant protein sources, had no effect on BW gain. Ruminal pH and ammonia N concentrations were higher (P<0.001) with the experimental diet versus the control diet, while they were not affected by defaunation. Nitrate concentrations in rumen fluid were decreased by defaunation on days 30 (P<0.001) and 60 (P=0.04), but not affected with the experimental diet. There was a main effect interaction for the nitrite concentration in the rumen fluid on days 60 (P<0.001) and 90 (P=0.02). Protozoa disappeared from the rumen of lambs fed the experimental diet, whereas protozoa in the rumen contents of lambs fed the control diet were highest on day 30, but decreased thereafter. Plasma glucose and urea N levels were higher (P<0.001) in lambs fed the experimental diet. On day 30, there was a main effect interaction on blood methemoglobin levels. Methemoglobin level in the blood increased when lambs were fed the experimental diet on days 30 (P<0.001) and 60 (P=0.01). Performance of lambs fed a diet containing urea and sulfur as an N source in place of plant protein sources was not affected by defaunation.