Prediction of apparent digestibility and voluntary intake of hays fed to sheep: comparison between using fibre components, in vitro digestibility or characteristics of gas production or nylon bag degradation

Abstract

The study compared using chemical components (i.e. crude protein (CP), neutral- and acid-detergent fibre or lignin (NDF, ADF and ADL) g/kg dry matter (DM), the in vitro digestibility (Tilley and Terry, 1963), the in situ (nylon bag) DM degradation (g/100 g DM) and gas production (ml/200 mg DM) techniques to predict voluntary daily intake (g DM per kg M0.75) and in vivo apparent DM digestibility (DMD) of 10 graminaceous hays individually offered ad libitum to four Merino male sheep. Gas production or DM degradation were determined after 6, 12, 24, 48, 72 or 96 h incubation and their characteristics described using the equation p = a + b (1 – e-ct). Intake and in vivo DMD of the hays were variable and poorly related (r = 0·52; P > 0·05). The in situ DM degradation was significantly (Y < 0·05) related to in vivo apparent DMD at 48 to 96 h incubation (i = 0·76 to 0·75) and to intake at 24 to 96 h (r = 0·71 to 0·75) incubation. However, fibre components, the in vitro digestibility or gas production were either related to daily intake or in vivo apparent DMD, but not to both on the same occasion. Accurate prediction of intake (r = 0·90; P < 0·05) and in vivo apparent DMD (r = 0·88; P < 0·069) were achieved using NDF, ADF, ADL and CP in a multiple regression. Using the (a + b) and the rate (c) of in situ DM degradation, both in vivo apparent DMD (r = 0·77; P < 0·05) and intake (r = 0·83; P < 0·05) were predicted with accuracy. However, using the (a + b) and (c) of gas production, only intake was predicted accurately (r = 0·87; P < 0·01). The lower performance of the gas test was attributed to the small contribution to gas production and higher buffering capacity resulting from protein fermentation. When data of the graminaceous and other data from leguminous hays were combined, the most accurate prediction of both intake and apparent digestibility was by using characteristics of in situ DM degradation followed by those of gas production. The latter was more accurate than using chemical components or the in vitro digestibility. Addition of CP in the multiple regression improved the prediction of intake and in vivo apparent DMD from characteristics of gas production. It was concluded that despite the need to overcome the problem of protein fermentation in the gas test, accurate prediction of both intake and apparent digestibility can be achieved simply from the degradation characteristics of foods.

Effects of cladode age on biomass yield and nutritional value of intensively produced spineless cactus for ruminants

“…Therefore, the kinetic variables of its IVDMD suggest that spineless cactus could be good forage to ruminants. Linear regression analysis indicated that CP alone in the model gave a high prediction of IVDMD, results which are consistent with those reported by Khazaal et al (1995). The improvement in the prediction of IVDMD was evident when CP, NDF and ADF were included in the model.…”

Kecernaan in Sacco Hijauan Leguminosa Dan Hijauan Non- Leguminosa Dalam Rumen Sapi Peranakan Ongole

“…ADF di dalam pakan memberikan korelasi negatif terhadap degradasi masing-masing hijauan pakan. Tingginya kadar fraksi serat pada pakan, selain itu lignifikasi pada tahap lebih lanjut juga dapat mengurangi aktivitas degradasi pakan oleh mikrobia rumen, besarnya kandungan lignin tentu saja secara tidak langsung akan memperkecil laju degradasi fraksi potensial terdegradasi (Khazaal et al, 1995). Menurut Van Soest (1994), ADF memberikan pengaruh yang tinggi pada kecernaan hijauan berkisar antara 75-88% dan kandungan ADF pada pasture digunakan sebagai indeks untuk memprediksi tingkat Tabel 6.…”

In vitroParameters as Predictors of Metabolizable Energy Values of Roughages

“…This case is in accordance with the studies and revealed that there were high correlations between in uiuo ME values of roughages and cell wall components such as NDF and especially ADF (Alcicek et al, 1997). In the study, ADL with GP gave a very low R2 value of 0.61 as compared to 0.81 value of Khazaal et al (1995) …”