Rice gluten meal as an alternative by-product feed for growing dairy calves

This experiment aimed at studying the nutritional characteristics and feeding value of rice gluten meal (RGM, a wet-milling by-product of rice) in growing dairy calves. RGM contained 464 g/kg of crude protein with 821 and 196 g/kg nitrogen (N) of borate-phosphate insoluble N and acid detergent insoluble N, respectively, which were higher (P < 0.05) than groundnut cake (GNC). In vitro gas production, organic matter digestibility and energy values were comparable between RGM and GNC. For in vivo trial, 18 Karan-Fries calves (6–12 months) were randomly assigned into three groups based on comparable body weight and age. The first group (GP-I) was fed concentrate mixture containing mainly GNC as protein source, whilst it was replaced by RGM up to 50 and 75 % on N basis, in second (GP-II) and third (GP-III) groups, respectively. Thus, RGM constituted 140 and 210 g/kg of concentrate mixture of GP-II and GP-III, respectively. In addition, all animals were offered chopped green maize and wheat straw for the whole experimental period of 90 days. Results revealed that there was no difference in intake and digestibility of nutrients, N balance, average daily gain (ADG) and feed efficiency among three groups. Nevertheless, RGM-based diets produced cost-effective ADG than GP-I. Furthermore, experimental calves did not differ in haematological variables like glucose, blood urea N, plasma proteins and non-esterified fatty acids. This study demonstrated that RGM could be incorporated successfully in the concentrate mixture, replacing 75 % of GNC without any discernable compromise in the performance of growing calves.