Composition and utilization in sheep of unwilted and wilted silages prepared from seeding year red clover (Trifolium pratense L.) cut at two maturity stages

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Red clover (Trifolium pratense L.) cultivar Florex was seeded in May and cut at the vegetative stage on 5 August or at the 20% bloom stage on 25 August. The cut material was stored as unwilted silage or, after 26–30 h of field drying, as wilted silage. The silage types prepared from vegetative herbage were compared in the first feeding trial using 12 sheep per silage type. The silage types prepared from the 20% bloom stage herbage were compared in a second feeding trial using the 24 sheep from the first trial. Unwilted silage prepared from vegetative herbage contained less total-N and butyric acid, and more acid detergent fibre and ammonium-N than when this herbage was stored as wilted silage. Unwilted silage prepared from the 20% bloom stage herbage contained more total-N, soluble-N and ammonium-N and less propionic acid than wilted silage produced from herbage of the same maturity. All the silages contained low levels of volatile fatty acids and lactic acid due to restricted fermentation. Silage DM intake and digestibility in sheep were not affected by the type of silage produced within each stage of herbage maturity. Unwilted silage prepared from vegetative herbage provided lower intake, faecal excretion and retention of total-N in sheep than when this herbage was used as wilted silage. Silage types prepared from 20% bloom stage herbage showed no difference in total-N utilization in sheep. It was concluded that the seeding-year red clover harvested as unwilted or wilted silage in late August, can be used as a high quality buffer feed to meet forage shortfall due to severe winter kill. Key words: Red clover, silage, intake, digestibility, N retention