Evaluation of in sacco Ruminal Degradation Profiles of Raw and Steamed Maize Cob and Their Effects in Replacing Maize Bran in Diets

Abstract

The degradation experiment was conducted using three healthy bulls fitted with permanent rumen canulas of 40 mm diameter. The bulls were fed cowpea husk ad libitum as the basal diet and supplemented with 500 g/day of a mixture of maize bran, cotton seed cake, and minerals in the ratio of 59:40:1 respectively. Three (3) gram of each sample was replicated two times and put into six (6) different nylon bags, inserted via permanent ruminal canula and left in the rumen for each incubation time: 3, 9, 12, 18, 24, 36 and 48 hours. The bags containing undigested residues were removed from the rumen after each incubation time and thoroughly washed under running tap water until the washing water was clear. The differences in weights of dry matter in the nylon bags before and after rumen incubation represented materials degraded in the rumen. Dry matter disappearance (washing loss) was determined by soaking three bags of each sample in warm water at about 40°C for 30 minutes. The bags were removed and washed under running tap water for some minutes. When the water became clear, the samples were dried in the oven at 65°C for 48 hours. The actual percentage of dry matter disappearance was then calculated. After compounding the diets, the raw and steam-treated maize cobs with 10% cotton seed cake across levels, there were increased rumen degradations (40.11 to 57.42%) at 48 hours incubation. The maize cob when incorporated with other feeds, can replace more expensive maize bran up to 50% with resultant high rumen degradation without health hazard to the animals.