Full-fat rice bran
In dairy cows, full-fat rice bran has been recommended as a source of fat (Nornberg et al., 2004). However, beef cattle and finishing cows supplemented with full-fat rice bran do not perform as well as animals supplemented with maize, soybean hulls or wheat bran (Gadberry et al., 2007; Osmari et al., 2008).
Heifers fed maize or soybeans hulls as energy-based supplements gained more body weight than heifers fed rice bran, but this product had no effect on calf birth and weaning body weight (Sanson et al., 2003).
In steers, full-fat rice bran has proved to increase DM intake when supplementing hay-based diets, green forage-based diets or sugarcane bagasse-based diets (Pal et al., 2004; Toburan et al., 1990; Alvarez et al., 1978). However, at low inclusion levels it had no effect on carcass yield or carcass weight (Goncalves et al., 2007).
Defatted rice bran
In dairy cows, a mixture of defatted rice bran and molasses sustained the same milk yield as maize concentrate (Chaudhary et al., 2001).
Defatted rice, fed as a supplement to grazing cows or cows fed on hay-based diets, improved hay DM digestibility, hay NDF digestibility and total diet DM digestibility. The cows increased their body weight, milk yield and milk fat content (Gadberry et al., 2006; Buaphan et al., 2006).
However, when defatted rice bran was compared to other brans, such as maize bran or wheat bran, it gave the poorest results: lowest milk yield and lowest digestible OM intake (Gadberry et al., 2006; Tahir et al., 2002; Singh et al., 2000).
Defatted rice bran increased energy intake and fibre digestibility in steers (Zhao et al., 1996), suggesting that fat content is detrimental to NDF digestibility (Gadberry et al., 2007). Calves supplemented with defatted rice bran gained more body weight than non-supplemented calves. In other studies, defatted rice bran gave similar body weight gain to wheat middlings but lower than those obtained with maize or full-fat rice bran (Gadberry et al., 2007).
In sheep, supplementing basal diets with full-fat rice bran seems to have positive effects. However, recommended inclusion levels vary from less than 20% to more than 40% depending on the basal diet (Nega et al., 2009; Tabeidian et al., 2009; Salinas-Chavira et al., 2008; Orden et al., 2000a; Orden et al., 2000b; Rivero et al., 2004).
In lactating goats, substitution of wheat bran with rice polishings (25%) reduced the feed cost of goat rations (Dutta et al., 2006).