THE ESTIMATION OF FEED INTAKE BY SHEEP ON A SILAGE DIET

The results of nineteen digestibility trials with sheep on different silages have been reported. From these data and from the results of forty trials with sheep carried out by Watson (15) it has been shown that Lancaster's method of calculating feed intake (9) can be applied to silages when the crude protein content is within the range studied (9–24% of the dry matter). For silages in this category, no advantage has been found in taking the nitrogen content of the silage dry matter into account in calculating feed intake.
The digestibility of crude protein and Lancaster's'constant'have both been correlated with the crude protein content of the silage dry matter for the fifty-nine trials considered (r = 0.767 and r = 0.452 respectively). Although it has been found unnecessary to take the protein content of silage into account in calculating dry matter intake when feeds containing 9.24% crude protein in the dry matter are used, evidence is presented which indicates that this factor is of considerable importance when herbage of low protein content is fed. The equation, which has been derived from the silage data considered, has been found to be valid when compared with the results of trials with fresh herbage and well preserved hays of low protein content.
The results of this work indicate that Lancaster's method is a suitable one for estimating the feed intake of animals engaged in self feeding of silage, provided the silage has been well preserved.