Prediction of nutritive value of rice straw, Ruzi grass and leuceana leaves, common feed for dairy cattle, using nylon bag Technique
1997
Boonlom Cheva-Isarakul(Chiang Mai University, Chiang Mai (Thailand). Faculty of Agriculture. Department of Animal Science) | Saowalak Yammuen-art(Chiang Mai University, Chiang Mai (Thailand). Faculty of Agriculture. Department of Animal Science) | Chantana Nuamnuan(Chiang Mai University, Chiang Mai (Thailand). Faculty of Agriculture. Department of Animal Science) | Kraisit Vasupen(Chiang Mai University, Chiang Mai (Thailand). Faculty of Agriculture. Department of Animal Science)
Nutritive value of 3 roughage commonly used as dairy feed in Thailand was evaluated using nylon bag technique. A total of 86 bags, 7x15 cm with a standard pore size of 40-60 mum was used. Approximately 2.5 g of air dry feed was put in each bag. The bags were incubated in the rumen of 4 fistulated cows (4 replicates) at 4, 8, 12, 24, 48, 72 and 96 hours. After withdrawn they were washed, oven dried and calculated using a NEWAY software program, in which A = washing loss or solubility (percent), A+B = potential degradability (percent), c = degradation rate (fraction/hr) and L = lag phase which is the time required before the insoluble material begins to disappear. Dry matter content of rice straw, ruzi grass and leuceana was 90.8, 20.3 and 29.7 percent, respectively. On dry matter basis, their organic matter contents were 85.9, 92.8 and 90.1 percent while their crude protein contents were 3.5, 5.2 and 22.4 percent. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) of the 3 feed were 82.4, 69.6, 42.6 percent and 56.4, 40.4 and 26.0 percent, respectively. Rice straw had lower solubility (A) and degradation rate (c) than ruzi grass and leuceana leaves (A = 10.0 vs 21.1 and 27.2 percent, c = 0.042 vs 0.061 and 0.108 fraction/hr). The potential degradability (A+B = 60.1 vs 71.5 and 73.2 percent) and lag time (L = 5.7 vs 3.6 and 2.6 hr) of rice straw were also the worst. When A, B and c values from nylon bag technique were used to predict dry matter intake (DMI). Digestible dry matter intake (DDMI) and growth rate according to the multiple regression proposed by Shem et al. (1995), the values were arther unreliable particularly fro rice straw. However they can be used to calculate an index value according to Orskov and Ryle (1990) which could be used for feed ranking. Leuceana leaves was the best followed by ruzi grass and rice straw respectively. Therefore nylon bag technique is considered as a good tool to evaluate feed quality.
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