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Sixty six compound feeds, given as supplements in feeding experiments with dairy and fattening cattle, were studied. It concerned 41 different formulations involving 22 raw materials. The rumen degradation kinetics (soluble, potentially degradable and undegradable fraction and the degradation rate) of organic matter (OM), crude protein (CP), starch and NDF as well as the digestibility of rumen escape protein in the intestines (EPdi) were measured with four cannulated cows. The fermentable organic matter based either on in vitro digestible OM (FOMdom) or on in situ data (FOMis), the fractions of protein (EP) and starch (ESTA) escaping the rumen, the true protein digestible in the small intestine (DVE) and the degraded protein balance in the rumen (OEB) were calculated according to the Dutch protein evaluation system. The mean values and standard deviations were: 636 +/- 37 g/kg DM FOMdom, 649 +/- 47 g/kg DM FOMis, 0.346 +/- 0.077 EP, 0.900 +/- 0.037 EPdi, 0.167 +/- 0.050 ESTA, 115 +/- 23 g/kg DM DVE and 20 +/- 27 g/kg DM OEB. The FOMis gave overestimated values for starchy feeds. The use of ingredient data from the Dutch feed tables were fairly reliable for calculating the above attributes for the compound feeds; the square root of the mean squared residual (measured-table) amounted to 32, 57, 8 and 10 g/kg for, respectively, FOMdom, FOMis, DVE and OEB and to 0.046, 0.026 and 0.027 for, respectively EP, EPdi and ESTA. If the ingredient composition is not known, determination of the washable fractions of OM, CP and starch is a simple and rapid method, which combined with one or more chemical parameters could give a good prediction of the in situ values. In the case of FOM and EP also a fairly good prediction could be obtained by in vitro incubation in respectively fungal enzymes or a buffer solution. The use of NIRS also resulted in an acceptable prediction accuracy for FOMdom, EPdi, DVE and OEB. (C) 2003 Elsevier Science B.V. All rights reserved.
|Translated title of the contribution||Rumen degradation characteristics of nutrients in maize silages and evaluation of laboratory measurements and NIRS as predictors|
|Journal||Animal Feed Science and Technology|
|Number of pages||14|
|Publication status||Published - 25-Oct-2002|