Effect of swath treatment on water loss during field‐wilting and on feeding value of perennial ryegrass silage

Abstract

The effect of spreading mown perennial ryegrass (Lolium perenne) herbage over the total ground area on water loss during field‐wilting was compared with leaving herbage in swaths (three swaths put together into one, occupying 0·18 of ground area) in three experiments. Spread crops were not tedded during wilting but were rowed up immediately before harvest. In all experiments, conventional silage‐making equipment was used on a field scale. Feeding value was assessed with lactating dairy cows and growing heifers (Experiment 1) and sheep (Experiment 3). The periods of field wilting were 48 h (Experiment 1), 24 h (Experiment 2) and both 24 h and 48 h (Experiment 3). Spreading the crop was associated with larger increases in loss of water in all three experiments compared with leaving grass in swaths. Losses of dry matter (DM) during wilting were similar in Experiment 2 but were higher for the swathed crop wilted for 48 h than for 24 h in Experiment 3. Spreading resulted in restricted fermentations associated with higher crop DM contents at ensiling. In Experiment 1 the concentrations of DM, ash and water‐soluble carbohydrate in silage were higher (P < 0·001) for spreading the crop and the concentrations of crude protein and neutral‐detergent fibre were lower (P < 0·05) than for swathed material. In Experiment 3, spreading was associated with higher concentrations of water‐soluble carbohydrates and ethanol and lower concentrations of fermentation acids, ammonia‐N and neutralizing value in silage. Voluntary DM intake of silage by dairy cows and heifers was higher for spread than for swathed material (P < 0·05), but in Experiment 3 (sheep) there were no significant differences between treatments in voluntary intake of DM. The increased intake by dairy cows of silage from spread herbage was reflected in increased concentrations of milk fat (P < 0·01) and protein (P < 0·05) but not in milk yield (P > 0·05). It is concluded that spreading herbage during field wilting prior to ensiling accelerates water loss and has the potential to improve the feeding value of the ensiled product.

Effect of extent and rate of wilting on nitrogen components of grass silage

“…() who demonstrated that silage quality considerably influenced milk yield in high‐producing dairy cows only when the concentrate content of the diet was low; (ii) varying feed components (e.g. concentrate type, inclusion of maize or legume silage) within the ration; (iii) spreading the crop during wilting, as opposed to wilting in swaths, thus increasing the rate of moisture loss (Wilkinson et al ., ); (iv) partitioning of energy gained from increased DMI into live weight gain rather than milk (Gordon et al ., ; Kokkonen et al ., ); (v) the greater influence of dirt contamination in wetter silages, leading to higher butyric acid and ammonia production (McDonald et al ., ); (vi) silage management and type of silo, e.g. bunker silage is prone to warming after opening, particularly if grass is high in DM (Spiekers et al ., ); and (vii) other factors affecting nutritive value and fermentation characteristics, DMI and milk production.…”

Towards improved silage quality – A review

“…Such methods include crop spreading to expose the maximum surface area to solar radiation (Wilkinson et al 1999), and crop conditioning to reduce plant resistance to moisture loss (Savoie et al 1993;Frost and Binnie 1999). Wilkinson et al (1999) increased drying rate by spreading swaths during wilting. Such swaths reached a higher DM concentration by ensiling.…”

Characteristics of baled silage made from first and second harvests of wilted and severely wilted forages

“…Concentrations of water‐soluble carbohydrates (WSC) in perennial ryegrass range from 108 to 228 g kg −1 DM, depending on growth stage (Wait and Boyd, 1953; Wilson and Collins, 1980). Wilkinson et al. (1999) reported that WSC concentrations in silage made from tedded perennial ryegrass were significantly higher than that of silage made from swathed material.…”

“…Concentrations of water-soluble carbohydrates (WSC) in perennial ryegrass range from 108 to 228 g kg )1 DM, depending on growth stage (Wait and Boyd, 1953;Wilson and Collins, 1980). Wilkinson et al (1999) reported that WSC concentrations in silage made from tedded perennial ryegrass were significantly higher than that of silage made from swathed material. Low WSC concentrations in herbage promote heterofermentation relative to homofermentation (Davies et al, 1998) and conversion of lactic acid into acetic acid (Merry et al, 1995).…”