| Popis: |
My thesis is focused on possible improvement of prediction of net energy lactation (NEL) and net energy fattening (NEV) concentrations by organic matter digestibility (OMD) which is determined by the laboratory method ELOS suitable for routine operations. This should improve current practice when the determination coefficients are taken from the stock-feeding tables. This method of OMD in vitro determination with ANKOM DaisyII Incubator allows serial digestion of more samples in one batch in the fermentation vessel en bloc which significantly decreases laboriousness of operation, filtration is not necessary anymore, and alternatively inoculum can be chosen according to the laboratory potential (rumen juice -- buffer, resp. clean cellulases). Prediction accuracy, when the cellulase preparations made in the Czech Republic with balanced cellulolytic and other activities were used in this experiment, proved to be sufficiently accurate and fully applicable for practical use within a wide range of grass samples. The accuracy of determination of OMD in vitro by ELOS method within values usual for grasses in technical maturity (grazing, conservation), i.e. 60 -- 80, demonstrates results which are practically identical (+-2.43 OMD units) to the Tilley, Terry (1963) method. Specific differences in growth rhythm of 7 tested grasses were stated (P 0.01), and the difference in heading of the earliest grasses (Fl - Hy 'Hykor', FA 'Kora' -- table 5) and late grass (LP 'Kentaur' -- table 5) was 3 weeks. The OMD value decrease is in the average of species, 7 dates of sample collection, two sites and two harvest years 4.44 units, decrease of NEL and NEV values by 0.42 MJ.kg-1 dry matter per week. |
