Digestibility, nitrogen metabolism, ingestive behavior and performance of feedlot goats fed high-concentrate diets with palm kernel cake

The aim of this study was to examine the effects of including palm kernel cake (0, 120, 240 or 360 g/kg) in highconcentrate diets for feedlot goats on digestibility, nitrogen metabolism, ingestive behavior and performance. Thirty-two non-pregnant, mixed-breed goats (average age: 1 year; initial body weight: 24.70 +/- 3.72 kg) were evaluated in a completely randomized experimental design. The intake of nutritional fractions responded quadratically (P<0.05) to dietary inclusion of palm kernel cake, whereas the digestibility coefficients of dry matter (P=0.010) and organic matter (P=0.006) decreased. Fecal (P<0.001) and urinary (P=0.005) excretions of nitrogen also decreased. Plasma gamma glutamyl transferase concentrations decreased (P=0.017), whereas a quadratic response was observed for the serum concentrations of alanine aminotransferase (P=0.017) and aspartate aminotransferase (P=0.003). Daily weight gain also responded quadratically (P=0.013), with maximum gain estimated at the palm kernel cake inclusion level of 107.7 g/kg. Palm kernel cake inclusion levels of up to 107.7 g/kg are recommended for high-concentrate diets for feedlot goats, as they improve production performance and do not compromise metabolic or behavior parameters.