Subabul leaf meal as a replacement of mustard cake in lamb diets

Abstract

A growth trial of 120 days duration was conducted on 16 crossbred lambs less than 6 months of age to study the replacement value of subabul leaf meal (SLM) for a costly and commonly used mustard cake (MSC). Lambs were divided into four groups (four lambs per group) that received a concentrate mixture providing 40% of the CP requirement. The remaining 60% was met through groundnut cake (GNC; T1), MSC (T2) and SLM to replace 50 (T3) or 75% (T4) of CP supplied by MSC. In addition, lambs consumed ad libitum a dried grass mixture. Dietary inclusion of SLM did not deleteriously affect nutrient or energy utilization. Intakes of DM, DCP and ME were similar among treatments, ranging from 69.7 to 78.7 g, 3.82 to 4.49 g and 149.1 to 151.8 kcal kg BW 0.75 day −1, respectively. Apparent digestibilities (%) of DM, OM, CP, EE, NDF, ADF and cellulose tended ( p>0.05) to be lower, but N balance (g day −1) tended ( p>0.05) to be increased by SLM. The intake and concentration of ME in the total diet ranged from 1256 to 1296 kcal day −1 and 1.88 to 2.15 kcal g −1, respectively and were comparable among treatments. Average daily gain (g) was similar among treatments (73, 65, 75 and 73 g day −1 for T1, T2, T3 and T4, respectively; Pooled SE, 8.72). However, feed cost per kg of weight gain for T4 was 19% less than for control diets (i.e. T1 and T2). Concentration of plasma protein and urea N in blood did not differ significantly among the treatments, but glucose concentration (mg dl −1) was lower ( p<0.05) for T1 (56.01) than for T2 (62.21), T3 (64.01) and T4 (61.59) treatments. It was concluded that SLM can safely and inexpensively replace part of MSC in growing lamb diets.