1998 Volume 44 Issue 3 Pages 248-254
Three experiments carried out to study effects of characteristics of feed and animal condition on voluntary intake. The voluntary feed intake measured as dry matter intake (DMI) with four dairy cows fed timothy hays ad libitum. The digestibility of chemical compositions of the timothy hays obtained from total collection method with sheep. The rate of degradation of fiber in the tureen was calculated from in vitro method. Mean daily DMI and DMI per metabolic body weight of four timothy hays ranged from 6.5 to 9.1 kg/day, from 56.9 to 78.8 g/kg^<0.75>, respectively. The daily DMI of timothy hays by dairy cows was closely related with organic b fraction (Ob), sum of organic cellular contents and organic a fraction (OCC+Oa), and acid detergent lignin (ADL). The daily DMI can predict from following regression equations; DMI=-0.18×Ob+19.5 (r=0.993), DMI=-0.50×ADL+12.1 (r=0.997), DMI=0.19×(OCC+0a)-1.6 (r=0.993). In addition, the daily DMI of timothy hays by dairy cows was closely related with retention time in the tureen, digestibility of each chemical compositions of the timothy hays and rate of degradation of fiber in the tureen. Similar values were observed in DMI per metabolic body weight. From those result it was cleared that each factor examined in this study effect on voluntary feed intake.
