Short communication Growth performance of faunated and defaunated Malpura weaner lambs

An experiment was conducted to study the effect of presence or absence of rumen ciliate protozoa on nutrient intake, its utilization, rate of body weight gain and feed conversion ef®ciency of lambs in post-weaning phase of growth. Forty ®ve weaned Malpura lambs, divided into three equal groups (G1, G2 and G3) were either defaunated by periodic dosing of sodium lauryl sulfate at the rate of 8 g/100 kg body weight (G1) or defaunated and refaunated (G2) or maintained faunated (G3). The lambs were fed for 90 days on 50:50 pala (Zizyphus nummularia) leaf and concentrate based complete feed. With care and segregation the defaunated lambs were maintained free of rumen protozoa for 47 days after which Entodinomorphid appeared while Holotrichs were not detected. The total and differential protozoa count was similar in refaunated and faunated lambs and the residual toxic effect of sodium lauryl sulfate if any was not detected. Even with similar dry matter intake in the three groups, body weight gain and feed conversion ef®ciency were higher in defaunated lambs. The digestibilities of cell and cell wall contents were generally poor in defaunated lambs while intake of digestible protein and energy were similar in the three groups. The lambs in the three groups were in positive nitrogen balance while percent N retention was higher in defaunated than in refaunated and faunated lambs. It was concluded from the study that with similar dry matter intake and plane of nutrition, the growth performance and feed conversion ef®ciency were better in defaunated than refaunated and faunated lambs. In spite of reduced digestibility of neutral detergent ®bre, acid detergent ®bre and cellulose, the metabolise energy availability for body synthetic activity was probably higher in defaunated lambs as evident from the observed production traits. # 2000 Elsevier Science B.V. All rights reserved.