Urea-treated neem (Azadirachta indica A. juss) seed kernel cake as a protein supplement for lambs

The performance of 12 male and 12 female Mandya Merino lambs weighing between 5.4 and 12.4 kg was investigated by feeding neem seed kernel cake (NSKC) after treatment with 2.5% urea. Lambs of each sex were allotted randomly to concentrate mixture containing either 30% groundnut cake (GNC) or 33% urea-treated neem seed kernel cake (UTNSKC). Over a period of 182 days the concentrate mixtures fed, to meet 70% of the protein requirements of the lambs, were given with oat hay offered ad libitum. Replacement of GNC by UTNSKC in the concentrate mixture depressed (P < 0.001) the digestibility of dietary dry matter (DM) (69.9 vs. 63.3), crude protein (CP) (71.1 vs. 65.1) and gross energy (69.9 vs. 64.3). Digestibility of ether extract (70.5 vs. 77.6) was increased (P < 0.001) and therewas no effect on crude ®bre (41.6 vs. 43.8) digestibility, whereas the daily intake of DM (72.51 vs. 65.77 g/M) and GE (1.33 vs. 1.21 MJ/M) were higher (P < 0.05) in lambs fed UTNSKC, dietary differences had no effect on digestible energy intake and N retention. The rumen liquor from lambs fed UTNSKC had lower concentrations of total volatile fatty acids (P < 0.01), total N (P < 0.01) and ammonia N (P < 0.01) and depressed activities of cellulase (P < 0.05), protease (P < 0.01) and urease (P < 0.01) enzymes. Average daily gains were similar (P > 0.05) in lambs fed UTNSKC (74.0 g) and GNC (80.3 g). More DM (7.08 vs. 8.04 kg kgÿ1) and CP (1.10 vs. 1.23 kg kgÿ1) were required for growth on the ration containing UTNSKC. Feeding UTNSKC had no effect on blood pro®le, wool growth and carcass characteristics. Kidneys from animals fed UTNSKC were enlarged (P < 0.05) as compared to those fed GNC. Microcalculi were observed in all lambs fed UTNSKC. The results indicated that feeding UTNSKC depressed the digestibility of nutrients, which was attributed to the low activities of enzymes in the rumen. # 2000 Published by Elsevier Science B.V. All rights reserved.