This study was amid to investigate animal response to replacement 15% of concentrate feed mixture (CFM) with ground mesquite pods without and with 4% Polyethylene glycol (PEG) 4000 in invitro and invivo experiments. In vitro rumen gas production values at 24h were 58.67, 55.0 and 61.67 ml/400mg for CFM1, CFM2 (15% mesquite pods) and CFM3(15% mesquite pods + 4%PEG4000) respectively. Dry matter digestibility (DMD %) was 63.58, 64.50 and 66.65% for CFM1, CFM2 and CFM3, respectively. In vivo experiment was done using 15 growing goat kids (10.49±1.29 Kg) which were randomly divided into three groups. Group one (G1) was fed on concentrate feed mixture (CFM) and pasture (desert grass, Panicumtidrgium), group two (G2) was fed on CFM with 15% ground mesquite pods and pasture and group three (G3) was fed on with 15% ground mesquite pods plus 4% PEG 4000. Using PEG 4000 in G3 resulted in increasing intake from pasture by 19.45 and 30.51% from pasture intake in G1 and G2, respectively. Digestibility coefficients were very close to each other’s. Values of NDF and ADF digestibility tended to increase in mesquite pods groups (G2 and G3) compared to control group (G1). Also, TDN% values were 74.46, 77.69 and 77.68% for G1, G2, and G3, respectively. Using PEG 4000 (G3) with mesquite pods had the best values over all groups in average daily gain (60.13 g/day),body weight gain (9.02 Kg) and final body weight (19.5 Kg).Serum parameters were under normal range of healthy goats. In general, using mesquite pods decreased feed cost per day by about 21% from control diet and PEG group as well.
