Effects of increasing supplementation levels of rice bran on milk production and fatty acid composition of milk in Saanen dairy goats

Abstract

In this study, the effects of four dietary supplementation levels of rice bran (RB) on milk yield and composition were examined in Saanen dairy goats. Four goats (initial bodyweight, 55.0 ± 7.1 kg) and four 21-day periods were used in a 4 × 4 Latin-square design. The diets contained 0, 5, 10, and 20% DM of RB, but were otherwise formulated to be 10.7 MJ metabolisable energy/kg and 18.8% crude protein/kg DM. Goats consumed the greatest amount of DM feed concentrate when fed the 5% RB diet (P < 0.01); however, DM forage intake was not significantly different between diets. Total DM intake of the 5% RB diet was significantly higher than that of the control diet (P < 0.05). Milk yield was the lowest from goats fed the 20% RB (P < 0.01). The protein concentration of milk was significantly lower in goats fed the control and 5% RB diets than in those fed the 10 and 20% RB diets (P < 0.01). However, milk protein production was not significantly different between diets. The concentration of fat in milk increased as the supplementation level of RB increased, although fat production did not differ between diets. The addition of RB increased the concentration of long-chain fatty acids (C16 and C18) in goat milk. No significant difference was found in milk lactose concentration between diets. Overall, the results indicate that RB supplements of up to 10% have no adverse effects on DM intake and milk production in dairy goats.