Abstract
Fattening and digestibility trials were conducted to evaluate growth performance, feed consumption, digestibility, and N balance in Najdi lambs fed diets supplemented with low quality date palm. In the fattening experiment, animals were randomly distributed into three groups, eight lambs each. The first group (C) was fed a control diet containing 50% Rhodes grass hay, 25% wheat bran and 25% ground barley grain. Two levels of date’s flesh of 10% (group D10) and 20% (group D20) were used to substitute the same levels from the concentrate part. In the digestibility trial, three animals from each group were housed separately in metabolism cages in order to collect feces and urine. Results of the fattening experiment revealed that replacing the concentrates with 10 or 20% date flesh was associated with a non-significant decrease in daily weight gain (148, 131 and 127
g/day for group C, D10 and D20, respectively). The respective feed intakes were significantly different (1167, 1028 and 877
g/day). The corresponding feed conversions (kg DM/kg gain) were 7.87, 7.82 and 6.92. In the digestibility trial, the digestibility of OM, CP, NFE, and CF decreased significantly as the date flesh in diets increased. The same pattern was recorded for TDN and DCP. Nitrogen balance decreased insignificantly in the diets containing date flesh compared to the control ration. From an economic point of view, diets supplemented with up to 20% dates could be used efficiently in feeding Najdi lambs without adverse effects on growth and digestion of nutrients.