Effect of supplementation containing polyethylene glycol (PEG)-6000 on intake, rumen fermentation pattern and growth in kids fed foliage of Prosopis cineraria

A study was designed to assess the effect of replacing groundnut cake (GNC) in a compounded feed mixture (CFM) with 50 g kg−1 DM of polyethylene glycol-6000 (PEG-6000) on performance of kids fed tannin-containing foliage of Prosopis cineraria. Thirty Kutchi weaner kids of similar body weight (10.31 ± 0.11 kg) and age (90 days) were divided into three homogeneous groups (HP, LP and LP-PEG). They were supplemented with 100 (first month), 150 (second month) and 200 g per day (third month) of CFM before being allocated to the range. Kids in HP received a standard CFM with groundnut cake; LP received CFM in which GNC was replaced with cereal grains and LP-PEG received CFM in which the cake was substituted with 50 g kg−1 DM of PEG-6000. All the kids were grazed as a flock from 08:00 to 17:00 h on a 35 ha plot of native range of India. From April to June they were fed freshly cut leaves of P. cineraria in the range. On DM basis P. cineraria leaves contained 159.2 g kg−1 crude protein (CP), 567.2 g kg−1 neutral detergent fibre (NDF), 360.0 g kg−1 acid detergent fibre (ADF) and 188.6 g kg−1 acid detergent lignin (ADL). CP digestibility was higher (P = 0.004) in HP (0.541) and LP-PEG (0.530) compared to LP (0.444). Digestible crude protein (DCP) (g per day) and metabolisable energy intakes (MJ per day) in HP, LP and LP-PEG were 84.4, 61.06 and 85.56; 12.76, 12.55 and 14.89, respectively (P = 0.004 and 0.025). Blood haemoglobin (Hb) level (g dl−1) was higher (P = 0.001) in LP-PEG (12.3) compared to HP (9.12) and LP (8.96). A similar trend was found in blood urea nitrogen (BUN; P = 0.008). Rumen ammonia N (mg dl−1) and total volatile fatty acid (mg dl−1) concentrations were higher (P < 0.05) in LP-PEG (7.34; 8.26) compared to HP (4.95; 7.12) and LP (4.27; 6.49). After 3 months of experimental period, body weight gain in HP and LP-PEG was similar (7.69 kg) and higher (P < 0.05) compared to LP (6.57 kg). These results indicate the possibility of substituting conventional high protein CFM with low protein CFM containing PEG-6000 in kids fed tannin rich foliage of P. cineraria. © 2003 Published by Elsevier B.V.