Abstract
From a winter harvest of autumn-sown Italian ryegrass, long cut, short cut and pressed cake hay were prepared. The three hays were solely fed to goats equipped with rumen cannulae and the digestibility of nutrients, rumen fluid characteristics and in situ disappearance of dry matter were determined. The content of fibrous components increased during hay-making and the increased proportion was the highest in short cut hay and the lowest in pressed cake hay. The digestibility of pressed cake hay was similar to those of the other hays except for protein which was lower in pressed cake hay. The digestibilities of NDF and hemicellulose of short cut hay were significantly higher than those of long cut hay. Goats given pressed cake hay showed lower ruminal pH than those given short cut hay while maintaining less concentrations of volatile fatty acids after feeding. Ruminal degradation characteristics of dry matter revealed that short cut hay had less soluble fraction but higher rate of degradation compared with long cut hay. The pressing of macerated Italian ryegrass further decreased the soluble fraction but potential degradability was not lowered despite of the removal of highly digestible nutrients. The rate of degradation was similar between long cut and pressed cake hay. These results indicate that the chopping before hay-making would alter the characteristics of ruminal digestion of Italian ryegrass while not affecting the whole tract digestibility. Pressed cake hay was comparable to long cut hay in terms of digestibility and rate of degradation in the rumen.
