*Department of Veterinary Physiology, Harayana Agricultural University, Hisar125 004, India.
Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal132001, India
Online published on 5 January, 2012.
Ammoniation of rice straw was tried at two levels of urea (4 and 5 per cent) and 2 levels of moisture (30 and 40 per cent by weight). Twelve Karan Swiss, male, rumen fistulated calves (2-2½ yrs) were divided in three equal groups and fed rice straw either untreated (A) or 4 per cent urea + 40 per cent moisture treated and ensiled for 30 d (B) or 5 per cent urea + 30 per cent moisture treated and ensiled for 30 d (C). The concentrate mixture was provided to meet requirements. DM intake through roughage did not differ (P < 0.05) between groups but intake through concentrate mixture was significantly (P < 0.01) lower in groups B and C. The mean TVFA concentration (m mole/100 ml SRL) was 11.52 ± 0.43 (A), 14.00 ± 1.19 B and 13.56 ± 0.92 (C) (P < 0.05). In both the groups fed urea treated rice straw, the acetate declined (P < 0.01) while propionate increased (P < 0.05). TVFA production rates (moles/d) were 9.36 ± 0.37 (A), 12.01 ±0.12 (B) and 11.92 ± 0.38 (C) (P < 0.05). The digestibility co-efficient of different cell wall components were higher in groups fed urea treated rice straw.
