Effect of Some Green‐crop‐drying Processes on the Digestibility and Voluntary Intake of Herbage by Sheep

Abstract

The effect of artificial drying under commercial conditionson the digestibility and voluntary intake of herbage by sheep was studied, using either van den Broek (900°C inlet temperature) or SwissCombi (1100°C inlet temperature) triple-pass drum-type driers. Organic-matter digestibility of chopped dried herbage was 8-3, 5-8 and 5-3% lower than that of fresh herbage in Experiments 1, 2 and 3, respectively. Packaging chopped dried grass into 'cobs' caused a further reduction in OM digestibility of up to 2-8%. Pre-milling plus packaging (i.e. 'pelleting') depressed OM digestibility of chopped dried grass by 5 to 6 percentage units. Digestibility of dried grass in its various physical forms was further reduced when offered ad lib.; the greatest fall (9-4%) occurred with pellets and the smallest fall (0 8-13%) with loose chopped material; cobs were intermediate at 4-3-7-0%.

Effect of rotary‐drum‐drier exit temperature and length of pre‐drying storage time on digestibility of dried grass cobs

“…It has been shown that comniercial production of dried grass cobs can lead to substantial reductions (8-6-9-6 percentage units) in organic matter (OM) digestibility when compared with the fresh crop (Marsh and Murdoch, 1975). In order to keep such reductions to a minimum, information on factors likely to affect digestibility during tbe drying process is required.…”