The Effect of Starchy Source Digestion on Alfalfa Hay Digestibility by in Vivo and in Vitro Methods

This study was conducted to evaluate the starchy feed effect (the wheat flour and the wheat starches grade1 and 2) on alfalfa hay digestibility using in vivo and in vitro methods. The in vivo experiment was achieved with 4 ruminally fistulated Makui sheep (BW, 43.20±1.2 kg) in a completely randomized design with a change over arrangement and the in vitro Telly and Terry experiment was conducted in a completely randomized design. In either experiment the DM and OM digestibility for mixed (starchy) rations was significantly higher than those of basal (alfalfa hay) ration, but the NDF digestibility of basal ration was higher than that of mixed ration. The rumen pH for alfalfa was the highest, and the lowest pH was obtained with the starch grade1 containing diet. The highest and the lowest correlation of regression equations were related to in vivo DM digestibility and the experimental mixed rations NDF digestibility, respectively. Results of this study showed that the starch grade 1 containing diet had a highest negative effect on the alfalfa hay fibre digestibility. Moreover, the regression equations may encompass better prediction of DM digestibility of mixed rations than that of the fibre digestibility.