Mass density of oat hay and lucerne hay as a feed evaluation characteristic

Author: F.J. van der Merwe and A.I. van Niekerk
Year: 1980
Issue: 2
Volume: 10
Page: 197 - 202

In the course of studies designed for evaluation of locally produce forages, significant differences (P ≤0,05) in voluntary intakes of lucerne hay and oat hay by sheep, were found. These differences could be partly explained by differences observed in protein content, digestibility and even palatability. However, when the dynamics of the digesta of the 2 feeds in the digestive tract of sheep were considered, it became apparent that there were important differences in space filling capacity and rate of fermentation. In further studies, the mass densities of samples of the 2 feeds, milled through different sized hammer mill screens, were determined. These varied from 0,097 g per cm3 in oat hay milled through the 32 mm screen, to 0,333 g per cm3 in lucerne hay milled through the 3 mm scene. These densities were then related to the voluntary intakes of the different physical forms of the two feeds by sheep. It was found, for example, that the intake of lucerne, hay and oat hay milled through the same screen, were, respectively, 80,3 and 41,8 g per kg W0.75 per day, while the volume intakes were 426 and 437 cm3 per kg W0.75 per day, respectively. It was concluded that space occupying characteristics of milled forages may have more important effects on voluntary intake than some of the other attributes usually taken into·consideration.

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