Evaluation of nutritional value of total mixed rations for dairy cows using near infrared reflectance spectroscopy (NIRS)

Abstract

V nalogi smo se osredotočili na ocenjevanje vsebnosti hranil v enolončnicah za krave molznice z metodo bližnje infrardeče refleksijske spektroskopije. Želeli smo preveriti ali ima ta fizikalna metoda potencial za ocenjevanje tovrstnih mešanic krme. Enolončnice smo pripravili v laboratoriju iz posušenih vzorcev krme. Hranilne vrednosti enolončnic smo prikazali v preglednicah. Na podlagi zmešanih enolončnic smo s pomočjo računalniškega programa WinISI izdelali napovedne enačbe. Napovedno moč teh enačb smo preverili z validacijskimi enolončnicami, rezultate skeniranja pa smo prikazali grafično ter v preglednicah. Parametri umeritvenih enačb za sestavine krme (surove beljakovine, surova vlaknina, surovi pepel, surove maščobe) in energijsko vrednost (presnovljiva energija, neto energija za laktacijo ) so bili odlični (R2>0,99), validacija z neodvisnim validacijskim setom vzorcev pa je pokazala, da so enačbe premalo robustne. Predlagali smo, da bi bilo treba napovedne enačbe izboljšati z večjim številom med seboj bolj raznolikih enolončnic.Our focus in this thesis was evaluation of nutritional value of mixed rations for dairy cows using near infrared reflectance spectroscopy. Our goal was to establish if this physical method has a potential to evaluate composition of mixed rations. The mixed rations were prepared in a laboratory using dried feed samples. The nutritional values of mixed ratios were presented in tables. The predictive equations were developed by the use of WinISI computer program. We have tested the accuracy of predictive equations using validation sample set. The results were presented in tabels and gaphically. Parameters of calibration equations for feed ingredients (crude protein, crude fiber, raw ash, raw fats) and energy value (metabolizable energy, net energy for lactation) were excellent (R2> 0.99), however, validation with an independent validation set of samples showed that equations are not robust enough. It was suggested that the predictive equations should be improved with a greater number of more variable mixed ratios

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