Comparison of two methods for fibre contents determination in forages | Primerjava dveh metod za določanje vsebnosti vlaknine v voluminozni krmi

Inglés. In 76 samples of Italian ryegrass, perennial ryegrass, timothy and red clover, harvested in different morphological stages, the crude fibre (CF) content was determined according to the method of Naumann and Bassler (1976) and neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) were determined according to the methods of Goering and Van Soest (1970). CF, NDF, ADF and ADL contents of the same samples were also determined with the use of filter bags and labelled as CFFB, NDFFB, ADFFB and ADLFB. In contrast to grasses, where the differences between NDF and NDFFB, ADF in ADFFB and ADL in ADLFB were small (in average the largest difference was 20 g kg–1 DM between ADF and ADFFB in perennial ryegrass), the differences between NDF and NDFFB, ADF and ADFFB, ADL and ADLFB contents in red clover were large (in average 46, 66 and 35 g kg–1 DM, respectively). The differences between CF and CFFB contents in grasses and red clover were not so large (in average teh largest difference was 17 g kg–1 DM in red clover). If the samples of red clover were rinsed with acetone before NDFFB, ADFFB and ADLFB contents determination (acNDFFB, acADFFB and acADLFB) the differences between them and NDF, ADF and ADL contents greatly diminished (in average to 15, 17 and 5 g kg–1 DM, respectively). The accuracy of the relationship between CF, NDF, ADF and ADL contents and fibre contents determined with the filter bags was measured with the coefficient of determination (R2) in standard error of the estimate (SEE). The best predictions for CF (R2 = 0.89, SEE = 1.73), NDF (R2 = 0.98, SEE = 1.73), ADF (R2 = 0.90, SEE = 1.73) and ADL (R2 = 0.69, SEE = 1.73) contents were those which contained as a single dependent variable CFFB, NDFFB, ADFFB and ADLFB of grasses and CFFB, acNDFFB, acADFFB and acADLFB of red clover. Results showed that the filter bag method is convenient for the determination of the CF, NDF and ADF contents, but is less suitable for the determination of ADF content.

Esloveno. V 76 vzorcih mnogocvetne ljuljke, trpežne ljuljke, mačjega repa in črne detelje, košenih v različnih fazah morfološkega razvoja, smo določili vsebnost surove vlaknine (SV) po metodi Naumann in Bassler (1976) ter vsebnosti v nevtralnem detergentu netopne vlaknine (NDV), v kislem detergentu netopne vlaknine (KDV) in v kislem detergentu netopnega lignina (KDL) po metodi Goering in Van Soest (1970). Vsebnosti SV, NDV, KDV in KDL v teh vzorcih smo določili tudi s pomočjo filtrskih vrečk in jih označili kot SVFV, NDVFV, KDVFV in KDLFV. Za razliko od trav, kjer so bile razlike med vsebnostmi NDV in NDVFV, KDV in KDVFV ter KDL in KDLFV majhne (v povprečju največ 20 g kg–1 SS med vsebnostma KDV in KDVFV pri trpežni ljuljki), smo pri črni detelji ugotovili velike razlike med vsebnostmi NDV in NDVFV (v povprečju 46 g kg–1 SS), KDV in KDVFV (v povprečju 66 g kg–1 SS) ter KDL in KDLFV (v povprečju 35 g kg–1 SS). Med vsebnostmi SV in SVFV tako pri travah kot pri detelji tako velikih razlik ni bilo (v povprečju je bila največja razlika 17 g kg–1 SS pri črni detelji). Če smo vzorce črne detelje pred določanjem vsebnosti NDVFV, KDVFV in KDLFV sprali z acetonom (acNDVFV, acKDVFV in acKDLFV), smo ugotovili, da se razlike v vsebnosti med njimi in vsebnostmi NDV, KDV in KDL močno zmanjšajo (v povprečju na 15, 17 oz. 5 g kg–1 SS). Stopnjo povezanosti med vsebnostmi SV, NDV, KDV in KDL ter vsebnostmi vlaknine v vzorcih, ki smo jih določili s pomočjo filtrskih vrečk, smo ugotavljali s koeficientom determinacije (R2) in standardno napako ocene (SEE). Najboljše ocene vsebnosti SV (R2 = 0,89, SEE = 1,73), NDV (R2 = 0,98, SEE = 1,73), KDV (R2 = 0,90, SEE = 1,73) in KDL (R2 = 0,69, SEE = 1,73) smo dosegli, ko smo v enačbe kot posamezne odvisne spremenljivke vključili SVFV, NDVFV, KDVFV in KDLFV trav ter SVFV, acNDVFV, acKDVFV in acKDLFV detelj. Rezultati so pokazali, da je metoda s filtrskimi vrečkami je primerna za določanje vsebnosti SV, NDV in KDV, ne pa tudi za določanje vsebnosti KDL.