Studies on the protein degradabilities of feedstuffs in Taiwan

The protein degradabilities of feedstuffs, roughages and by-products that are commonly used in ruminant rations, were measured by the in situ nylon bag method. ry dairy cows were fistulated in the rumen for the in situ nylon bag studies. Twenty-eight different feedstuff samples were placed in 4.5 × 6.5 cm nylon bags, and were then incubated in the rumen for different periods of time (0, 2, 4, 8, 12 and 24 h). Under 8% of rumen solid outflow rate, the percentages of the calculated protein degradability were: corn gluten meal, 8.8; feather meal, 29.1; soya pomace, 79.1; brewers grain, 37.1; distillers grain, 53.9; meat and bone meal, 51.9; wheat bran, 76.8; corn, 34.6, respectively. The size of nylon bag was changed to 10 × 20 cm, and the method of bag suspension was also changed, whilst the incubation period was extended two additional periods of 48 and 72 h in the second trial. The results of the protein degradabilities in 8% ruminal outflow rate were as follows: pangola hay. 38.6; soya pomace, 83.3; corn silage, 75.6; rice bran, 52.5; napier grass, 34.7; distillers grain, 60.1; brewers grain, 54.9; alfalfa hay, 71.8; fish meal, 37.5; soybean meal, 68.0; beancurd pomace, 61.7, respectively. All the degradabilities mentioned were uncorrected for influx microbial nitrogen. he smaller standard deviation of the crude protein disappearance rate in the large nylon bags (trial 2), it recommended the size of the nylon bags is 10 × 20 cm instead of 4.5 × 6.5 cm.