A simple isocratic h.p.1.c. technique was developed for the simultaneous quantitative analysis of lactic, formic, acetic, propionic, isobutyric, n-butyric and isovaleric acids in aqueous acid extracts of silage. An Aminex HPX-87H strong cation exchange resin column at 41"C, 0.0025~ H2S04 mobile phase and ultraviolet detector at 210 nm were utilised. Estimated recoveries of acids added to silage ranged from 98.2 to 103.5%.

Conditioning may greatly increase the drying rate of cut forage during the initial stages of drying. Such results may be particularly useful for silage systems (as opposed to haymaking). This study was conducted to determine the drying rate and losses in six field wilting trials on pure stands of alfalfa (Medicago sativa L.) and Italian ryegrass (Lolium multiflorum Lam.) when treated with different types of mower-conditioners (rubber rolls; plastic or steel flails). Drying was measured by calculating the water loss rate from two subsequent hourly weights of swath portions placed on trays. Dry matter (DM) losses were estimated on 1.2-m lengths of swaths immediately after cutting. The steel flail conditioner provided faster drying than the other conditioning types for both crops. The effect of the rubber roll conditioner was limited due to the swath structure, especially with forage surface densities higher than 0. 7 kg D M m -z. Tedding positively interacted with the conditioning treatment to increase the drying rate, especially when forage was conditioned with the rubber roll machine. Shatter losses from alfalfa were higher for the flail conditioner, ranging from 3.6 to 10.2%, and with greater loss of crude protein. The DM losses were always lower than 2.5% for Italian ryegrass. The most severe conditioning (steel flails) followed by tedding is appropriate for grass, as it significantly reduces the wilting time without affecting DM loss. However, a less severe conditioning (rubber rolls) without tedding is more appropriate for wilting alfalfa, to avoid excessive leaf and protein loss.

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