Microbial community dynamics and their contributions to organic acid production during the early stage of the ensiling of Napier grass (Pennisetum purpureum)

The study aimed to disclose the microbial community dynamics and their contributions to organic acid production during the ensiling of Napier grass. Napier grass was harvested at the vegetative growth phase and ensiled for 30 days. Three silos were opened after 1, 2, 3, 5, 7, 14, and 30 days of ensiling respectively. The intensive fermentation was observed during the initial stage of ensiling, indicated by lower pH (<4.0) on d 2 of ensiling. Lactic acid (LA) was the primary fermentation product, although acetic acid (AA) concentration rapidly increased and LA/AA concentration gradually decreased after 3 days of ensiling. The ethanol concentration was already 11.8 g/kg DM on d 1 of ensiling and then remained stable until the end of ensiling. Lactococcus was the predominant genus during the initial 2 days of ensiling, and then, it was gradually replaced by Lactobacillus. The increase in ammonia nitrogen and butyric acid concentration after 7 days of ensiling was attributed to the growth of Clostridia, which is favored by the high moisture concentration in the Napier grass. The natural ensiling of Napier grass displayed LA-type fermentation and was dominated by the fermentation of Lactobacillus and Lactococcus. Lactobacillus is mainly responsible for the LA production during the ensiling of Napier grass.     

Soil water dynamics,herbage production and water use efficiency of three tropical grasses: Implications for use in a variable summer‐dominant rainfall environment,Australia

In the moist mid‐latitudes of eastern Australia, soil water dynamics, herbage production and water use efficiency (WUE) were monitored during 2006–2008, for five perennial pastures: digit grass (Digitaria eriantha), Rhodes grass (Chloris gayana), forest bluegrass (Bothriochloa bladhii), native grass (Bothriochloa macra and Rytidosperma bipartita dominant), lucerne (Medicago sativa); and two forage crops: oat (Avena fatua) and sorghum (Sorghum bicolor). Ground cover formed more quickly in Rhodes grass and lucerne (>70% ground cover in 120 and 175 days after sowing [DAS] respectively) than in forest bluegrass and digit grass (245 and 365 DAS respectively). Values of maximum extractable water (MEW) for Rhodes grass and lucerne were similar (180–242 mm), while values for digit grass and forest bluegrass (129–175 mm) were equal to or greater than those for native grass, and two annual forage crops (77–144 mm). Lucerne expressed the maximum root depth (1.46 m), while values for the tropical grasses (0.96–1.39 m) were greater than native grasses and forage crops (0.87–0.96 m). Native grasses (6.5–12 t DM/ha) had the lowest herbage production, which resulted in values of WUE that were significantly less than most other treatments (16–21 vs. 23–43 kg DM ha^?1 mm^?1). Digit grass (33–34 kg DM ha^?1 mm^?1) had higher WUE compared with the other tropical grasses (20–27 kg DM ha^?1 mm^?1). The data collected here suggest that a forage system comprising digit grass, lucerne and forage oat would provide high production and WUE in this environment.     

A comparison of the ensilage, in an anaerobic cabinet, of grass, either fresh or when thawed after deep freezing

The suitability of freezing a large amount of grass from a single harvest for use in a series of experiments to investigate silage fermentation and its manipulation was examined. Perennial ryegrass, harvested in late June, was ensiled in sterile polythene bags inside an anaerobic cabinet; some was also stored frozen at -20°C for up to nine months before ensiling in a similar manner. The course of fermentation was followed using not only conventional chemical and microbiological analyses, but also by measuring microbial metabolic activity in vitro. Freezing and thawing affected the chemical composition and the microbial populations on the grass, and there were differences in the changes occurring in thawed grass during ensilage, probably related to damage to plant cells and impaired microbial activity associated with freezing and thawing. For both the grasses and the silages made from them, it was clear that the number of microorganisms present was not a reliable guide to microbial metabolic activity. Although the fermentation of frozen-and-thawed grass did not simulate precisely the fermentation occurring with fresh grass, it is concluded that, when used judiciously, the ensilage of thawed grass can be a useful experimental tool, particularly in the initial screening of manipulants of fermentation.     

In vitro fermentation patterns and methane production of sainfoin (Onobrychis viciifolia Scop.) hay with different condensed tannin contents

Sainfoin (Onobrychis viciifolia Scop.) is a perennial legume recently reappraised for some positive characteristics leading to highly satisfactory animal performance. Sainfoin’s characteristics may be partly explained by the presence of moderate levels of condensed tannins (CTs) able to protect dietary protein from microbial degradation in the rumen. Decreased CH₄ emissions have been reported for ruminants consuming CT‐containing forage. The aim of this study was to evaluate the effects of CT content on the in vitro fermentation characteristics and kinetics and methane production of four samples of O. viciifolia cut at different phenological stages. Sainfoin hays and one sample of alfalfa hay were incubated at 39°C in anaerobiosis using the in vitro gas production technique. The chemical composition, tannin content and fermentation characteristics and kinetics of sainfoin samples were significantly affected by phenological stage. After 48 h, the CH₄ production in sainfoin hays showed a tendency to increase with the advancement of phenological stage [from 38·6 to 49·8 mL g⁻¹ of degraded organic matter (OM)]. The best period to cut sainfoin for hay making is between early and late flowering, when the forage combines high OM digestibility, low CH₄ production and more efficient microbial fermentation.     

Effects of shredding on silage density and fermentation quality

The effects of shredding forages on the density and fermentation quality of the resulting silages were studied. Lucerne (Medicago sativa L.), red clover (Trifolium pratense L.), perennial ryegrass (Lolium perenne L.) and a grass–clover mixture were harvested and wilted indoors for 1–2 days. The dry‐matter content of the forages after wilting was 192 g/kg, 192 g/kg, 237 g/kg and 214 g/kg respectively. The forages were then either unprocessed or shredded once (1×) or four (4×) times using a novel laboratory shredder and were ensiled in laboratory‐scale silos. Fermentation was terminated after either 50 or 113 days of ensiling. Density and the fermentation weight losses of the silages were recorded. Initial density of the silages was considerably increased with increased intensity of shredding (p < 0.01). The initial density (DM basis) of the 4× shredded silages ranged from 177 to 236 kg DM/m³ whereas it was 124–163 kg DM/m³ in non‐shredded silages. The 4× shredded silages had the greatest fermentation weight loss at day 1 of ensiling (p < 0.01). Overall fermentation weight loss after 113 days of ensiling was reduced in the 4× shredded silages (p < 0.01). Shredding increased L‐lactate concentration and reduced pH of the silages (p < 0.01). The NH₃ concentrations were reduced by 25%–46% in 4× shredded silages and butyrate concentrations were reduced by 76%–97% in shredded silages in comparison to non‐shredded silages (p < 0.01). Shredding improved initial density and fermentation quality of silages while reducing overall fermentation weight losses.     

The choice of grass species to combat desertification in semi‐arid Kenyan rangelands is greatly influenced by their forage value for livestock

Livestock production is the main source of livelihood in the arid and semi‐arid lands in Africa. However, desertification characterized by vegetation degradation and soil erosion is a major threat to the sustainability of land‐based production systems. Native rangeland forage species Cenchrus ciliaris L. (Buffel grass/African foxtail grass), Eragrostis superba Peyr. (Maasai love grass) and Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass) have been used to combat desertification. The objectives of the study were to identify the best‐suited native grass species to combat desertification in a semi‐arid environment in Kenya and to identify the preferred grass species among the agropastoralists in the area. Percentage basal cover, plant densities and frequencies of the three grasses in pure stands and mixtures were estimated. Grass species preferences were through household survey and focus group discussion. Results showed a significant difference (P < 0·05) in plant densities and cover estimates: E. macrostachyus was ranked first; C. ciliaris and E. superba were ranked second and third respectively. The agropastoral farmers, however, preferred E. superba followed by C. ciliaris and E. macrostachyus, a reverse trend. These results suggest that the choice of grass species to combat desertification is influenced more by its contribution as a source of forage for livestock than its contribution for rehabilitation purposes.     

Tensile fracture properties of seven tropical grasses at different phenological stages

The intake of forage grasses by grazing ruminants is closely related to the mechanical fracture properties of grasses. The relationship between the tensile fracture properties of grasses and foraging behaviour is of particular importance in tropical reproductive swards composed of both stems and leaves. This study (i) quantified and compared the tensile fracture properties of stems and leaves of seven tropical grass species and (ii) provided insight into the underlying plant traits that explain differences in fracture properties between species. Fracture force, tensile strength, fracture energy and toughness of stems (in various phenological stages) and leaves were measured and compared among five introduced tropical grasses (Cenchrus ciliaris, Chloris gayana, Digitaria milanjiana, Megathyrsus maximus (syn. Panicum maximum), Setaria sphacelata) and two native tropical grasses (Setaria surgens and Dichanthium sericeum). Species differed significantly in fracture force and fracture energy, with stems and leaves of C. ciliaris and S. surgens requiring less force and energy to fracture and stems and leaves of M. maximus and S. sphacelata requiring more force and energy to fracture in comparison with the other species. Differences in tensile strength and toughness were less pronounced. The differences among species in fracture force and energy mainly resulted from differences in cross‐sectional area of plant parts rather than from differences in tensile strength and toughness.     

Digestion and nitrogen metabolism in beef cattle and in vitro rumen fermentation of autumn grass differing in fertilizer nitrogen application rate

Beef cattle partition dietary nitrogen (N) into meat or excrete it mainly in faeces and urine, which can contribute significantly to water and air pollution. The effects of two inorganic nitrogen (N) fertilizer application rates—15 (LN) or 80 (HN) kg N/ha—to Lolium perenne‐dominant swards in autumn, on herbage chemical composition, intake, digestion and N balance in beef cattle, and in vitro fermentation and methane production were studied. Four growing beef steers used in a 2 × 2 crossover design experiment were offered zero‐grazed grass harvested 21 days post‐N application between July and October. The same grasses were incubated in an eight‐vessel rumen simulation technique in a randomized complete block experiment. Grass dry‐matter (DM) concentration was 26 g/kg lower and crude protein (CP) concentration was 35 g/kg DM higher for HN compared to LN. There was no difference in herbage DM intake or in vivo DM digestibility between treatments. Nitrogen intake and the digestibility of N were higher for HN compared to LN. Total and urine N loss were 41 and 45 g/day greater, respectively, for HN compared to LN, but faecal N loss did not differ between treatments. The quantity of N retained and therefore N‐use efficiency did not differ between LN and HN (25% vs. 22%). In vitro rumen pH and ammonia‐N concentrations were higher for HN compared to LN, whereas volatile fatty acid concentrations and molar proportions did not differ between treatments. In vitro methane and total gas production were 0.9 mmol/day and 280 ml/day lower for HN than LN respectively. Under the particular conditions of this experiment, reducing fertilizer N application rate reduced total and urinary N excretion, which has potential environmental benefits; however, methane output measured in vitro was increased.     

Distribution and characterisation of fructan in wheat milling fractions

Structure and health effects of inulin-type fructans have been extensively studied, while less is known about the properties of the graminan-type fructans in wheat. Arabinoxylan (AX) is another important indigestible component in cereal grains, which may have beneficial health effects. In this study, the fructan content in milling fractions of two wheat cultivars was determined and related to ash, dietary fibre and AX contents. The molecular weight distribution of the fructans was analysed with HPAEC-PAD and MALDI-TOF MS using ¹H NMR and enzymatic hydrolysis for identification of fructans. The fructan content (g/100 g) ranged from 1.5 ± 0.2 in flour to 3.6 ± 0.5 in shorts and 3.7 ± 0.3 in bran. A correlation was found between fructan content and dietary fibre content (r = 0.93, P < 0.001), but with a smaller variation in fructan content between inner and outer parts of the grain. About 50% of the dietary fibre consisted of AX in all fractions. The fructans were found to have a DP of up to 19 with a similar molecular weight distribution in the different fractions.     

Divergent effects of defoliation intensity and frequency on tiller growth and production dynamics of Pascopyrum smithii and Hesperostipa comata

Rotational stocking theoretically enables regrazing of regrowth, but regrowth may be limited in xerophytic vegetation. We tested the hypothesis that regrowth would be slow and fixed in Hesperostipa comata (a caespitose, drought‐tolerant grass), while growth would be flexible in Pascopyrum smithii (a rhizomatous, less drought‐tolerant grass) under increasing defoliation and moisture, by assessing tiller growth rates, population dynamics and plant yield on marked plants in a Dry Mixed Grass prairie. Plots were clipped in late summer to simulate a deferred control, or intermittently during the growing season (May–August) at high intensity–low frequency (HILF), low intensity–high frequency (LIHF) or high intensity–high frequency and crossed with two water treatments (ambient and addition) in both a xeric upland and a mesic lowland. Growing season defoliation increased tiller growth rates of P. smithii in the upland, whereas HILF and LIHF reduced growth in the lowland. All defoliation regimes increased tiller growth for H. comata. Tiller populations of H. comata increased with frequent defoliation, while tiller populations of P. smithii decreased regardless of defoliation regime. Frequent defoliation, regardless of intensity, reduced yield relative to the deferred control for both grasses. While water addition consistently increased growth rates and reduced differences in tiller number among defoliation treatments, the regrowth of both grasses remained similar under varied defoliation with ambient moisture. High moisture conditions also promoted regrowth more in P. smithii compared to H. comata. In summary, neither grass species displayed an inherently fixed or flexible tiller or plant yield response in response to defoliation or moisture.     

Identification,ecological evaluation and phylogenetic analysis of non‐symbiotic endophytic fungi colonizing timothy grass and perennial ryegrass grown in adjacent plots

Non‐systemic endophytes coexist with grasses and produce positive or negative effects for the host. In agricultural grasses, endophytes such as Epichloë spp. (formerly: Neotyphodium spp.) enhance the biometric parameters and agricultural value of grass biomass and seeds. Some endophytic fungi produce active substances that exert a negative influence on grass‐fed livestock. There is a general scarcity of studies investigating other endophytic fungi, the species composition of fungal communities, fungal species capable of colonizing different grasses and endophyte transfer between grass taxa. This study aims to fill in the existing knowledge gap by describing the relationships between fungal species and grass species. Timothy grass (Phleum pratense L.) is more readily colonized by endophytic fungi than perennial ryegrass (Lolium perenne L.), and the ratio of fungi isolated from the above species was determined at 3:1. Ecological indicators, especially diversity, were also higher in the fungal community colonizing timothy grass. The vast majority of the isolated fungi were ascomycetes. In addition, two Basidiomycota isolates and three Oomycota isolates (Phythium acanthicum) were also obtained from timothy grass. The most prevalent fungal species were Alternaria alternata, Microdochium bolleyi and Epicoccum nigrum. An analysis of minisatellite DNA regions revealed high levels of genetic polymorphism in A. alternata, whereas the remaining isolates were characterized by low levels of genetic variation or genetic homogeneity. The transfer of endophytic fungi between grass species was determined, which was one of the most important observations made in the study. The Sørensen–Dice coefficient reached 50%, which indicates that all fungal species isolated from perennial ryegrass are capable of colonizing timothy grass.     

Changes in soil organic carbon pools in a long‐term trial with perennial fodder crops in acid soils of north‐east India

Efficient estimation of soil organic carbon (SOC) is vital for understanding and monitoring the effect of perennial fodder crops in conserving SOC. In subtropical regions, there is limited information on SOC accumulation and its allocation into different pools under long‐term grasses and legumes. Therefore, we investigated the dynamics of SOC in a 20‐year‐old field trial with seven perennial grass species and a legume in a Typic Paleudalf soil under subtropical climate in north‐east India by analysing oxidizable organic C (C_oc) and its fractions of very labile (C_VL), labile (C_L), less labile (C_LL) and non‐labile (C_NL), microbial biomass C (C_mic) and mineralizable C (C_min). Growing perennial fodder crops increased SOC in the 0–0.60 m soil depth from 19.9%–39.6% compared with the conventional cultivation with maize (Zea mays). The relative efficacy of the fodder species to SOC accumulation was Setaria sphacelata = Brachieria rosenesis > Panicum maximum cv. Makunia = Arachis pintoi > Panicum maximum cv. Hamil > Paspalam conjugalum = Pennisetum purpureum > Thysanolaena maxima. Among the analysed fractions, C_VL, C_L, C_LL and C_mic were influenced most by the fodder crops and the active pools (C_VL+C_L) constituted 71.6% of the SOC. The results indicate that under the tested subtropical climate, soil under perennial grasses and legumes conserves organic C and that most of the SOC is in labile pools of short residence time.     

Potential of the indigenous desert grasses of the Arabian Peninsula for forage production in a water‐scarce region

Indigenous perennial grasses are widely distributed in the Arabian Peninsula. Their survival under limited rainfall and grazing suggests a potential role as grassland species and for rehabilitation of degraded rangelands. Forage productivity, seed production and water‐use efficiency (WUE) was determined over 2 years for four indigenous grasses: buffel grass (Cenchrus ciliaris L.), dakhna (Coelachyrum piercei Benth.), da’ay (Lasiurus scindicus Henr.) and tuman (Panicum turgidum Forssk.) together with one exotic species, rhodes grass (Chloris gayana Kunth) in the central region of the United Arab Emirates. Three irrigation treatments were used: R1 (1858–6758 m³ ha^?1 year^?1), R2 (929–3379 m³ ha^?1 year^?1) and R3 (464–1689 m³ ha^?1 year^?1). Buffel grass had the highest dry‐matter (DM) yield under all irrigation treatments. The average DM yield of buffel grass was 14·6 and 15·1 t ha^?1 in the 2 years which was significantly higher than that for the other grasses with dakhna having the lowest DM yields. The WUE of 0·7 and 0·8 kg DM m^?3 in the 2 years for buffel grass was significantly greater than for the other grasses. Buffel grass showed the highest increase in WUE in both years when the irrigation was reduced from treatment R1 to R3. The results suggest that the desert grasses of the Arabian Peninsula, such as buffel grass, could be useful grass species in reducing the use of scarce irrigation water provided that seed production can be increased.     

Contribution of Medicago sativa to the productivity and nutritive value of forage in semi‐arid grassland pastures

The inclusion of legumes in semi‐arid native grasslands may promote the productivity and nutritive value of forage. This study was designed to assess the effect of legumes (the introduced legume Medicago sativa or the native legume Dalea purpurea) and soil P fertility (addition of 0, 50, or 200 P₂O₅ kg/ha at seeding) on the dry matter and nutrient content of native grasses mixtures, compared with the commonly used introduced forage grass Bromus biebersteinii grown with M. sativa. Plant harvests were performed in September 2008, July 2009 and September 2009. Plants nutrient content, δ¹⁵N value and dry matter were analysed. Results show that the M. sativa enhanced the N and P concentrations of native grass mixtures early in the summer, as well as the N concentration in Bouteloua gracilis in late summer of the driest year, 2009. The higher AM fungal diversity promoted by M. sativa was positively correlated with the dry matter and nitrogen uptake of M. sativa and with the P concentration of native grasses, in early summer. Overall, this study shows that M. sativa promoted beneficial AM fungal taxa and improved forage production in the semi‐arid prairies.     

Impacts of dormancy‐regulating chemicals on innate and salinity‐induced dormancy of four forage grasses native to Arabian deserts

The effects of dormancy‐regulating chemicals (DRCs) on alleviating innate and salinity‐induced dormancy (SID) were assessed in seeds of four perennial forage grasses (Pennisetum divisum, Sporobolus spicatus, Coelachyrum brevifolium and Centropodia forsskalii). These grasses have the potential to be used for restoration or rehabilitation of degraded rangelands of the Arabian Gulf deserts. The four species showed various levels of innate dormancy. Germination of seeds stored for 2 months was not enhanced by any of the five studied DRCs in both C. brevifolium and P. divisum, but significantly improved by thiourea, fusicoccin and gibberellic acid (GA) in C. forsskalii and by thiourea, fusicoccin and nitrate in S. spicatus. Salinity had a significant negative effect on all the studied grasses. Sporobolus spicatus was more tolerant to salinity, compared with the other species. The effect of DRCs on alleviating SID depended on species. Whereas DRCs had little effect on alleviating SID in C. forsskalii and P. divisum, they greatly alleviated it in S. spicatus and C. brevifolium. Partial alleviation was observed by fusicoccin in C. brevifolium and by GA, kinetin and thiourea in C. forsskalii. Nitrate, fusicoccin and GA resulted in a complete alleviation in S. spicatus seeds in 200 mm NaCl.     

The presence and location ofErwinia carotovora subsp.carotovora (Jones) Bergey et al. in the gut of adultDrosophila melanogaster (Meigen)

The potato blackleg bacteriumErwinia carotovora subsp.carotovora (Jones) Bergey et al. was found in feces and regurgitated material obtained from surface sterilized adult fruit flies,Drosophila melanogaster (Meigen), that had fed for five hours on nutrient agar cultures of the bacterium. The highest levels of bacteria were obtained from fecal material and it is likely that this is the source of most of the inoculum carried by these vectors. The bacteria were found to be present in the foregut, midgut, and hindgut ofD. melanogaster. The largest number of bacteria were in the foregut with the population level decreasing as distance down the digestive tract increased. It is probable that the association between the vector and the bacterium is accidental. The probability that the insect aids survival of the bacterium by protecting it from adverse environmental conditions is suggested.     

In vitro fermentation kinetics and end-products of cereal arabinoxylans and (1,3;1,4)-β-glucans by porcine faeces

Purified and semi-purified polysaccharides characteristic of cereals were fermented in vitro with a pig faecal inoculum, using the cumulative gas production technique, to examine the kinetics and end-products of fermentation after 48 h. It was shown that arabinoxylan and mixed linkage (1,3;1,4) β-glucan were rapidly fermented if soluble, while less soluble substrates (insoluble arabinoxylan, maize and wheat starch granules, and bacterial cellulose) were more slowly fermented. Relevant monosaccharides were fermented at very similar rates to soluble polymeric arabinoxylan and β-glucan, showing that depolymerisation was not a limiting step, in contrast to some previous studies. Bacterial cellulose is shown to be a useful model substrate for fermentation of plant cellulose which is difficult to obtain without harsh chemical treatments. Fermentation end-products were related to kinetics, with slow carbohydrate fermentation resulting in increased protein fermentation. Ratios of short-chain fatty acid products were similar for all arabinoxylan and β-glucan substrates.     

Mice find endophyte‐infected seed of tall fescue unpalatable – implications for the aviation industry

Bird strike is a significant problem for the aviation industry, caused in part by the attractiveness of the grass surrounding airports to birds. Endophyte‐infected grasses such as Avanex^® have been shown to reduce bird populations at airports through the production of secondary metabolites. These metabolites are unpalatable to herbivorous, omnivorous and granivorous birds and are known to reduce insect densities, thereby making the sown areas less attractive to insectivorous birds. Raptors also provide a bird‐strike threat which could be reduced by controlling mouse populations around airports. In this study, the effect of endophyte‐infected seed on mouse feeding behaviour has been investigated. By performing a choice trial offering diets containing endophyte‐infected and endophyte‐free tall fescue seed, it was shown that endophyte‐infected seed was less palatable to mice (P < 0·001 in a 14‐d trial). Furthermore, when diet positions were reversed, mouse feeding behaviour was modified to again select endophyte‐free material (P < 0·001 over a further 14 d). This result shows that endophyte‐infected grasses could not only be used in the control of bird populations but they also have the potential to control mouse populations which in turn would decrease the number of raptors. This use of endophyte‐infected grasses in areas surrounding airport runways shows great promise for the aviation industry.     

Economic comparison of forage production from annual crops, perennial pasture and native grassland in the alpine region of the Qinghai-Tibetan Plateau, China

Economic costs and benefits for different grassland production systems were analysed. Comparisons included one native grassland (alpine meadow dominated by sedges) system, four perennial monocultures of smooth bromegrass (Bromus inermis Leyss, SB), Siberian wild ryegrass (Elymus sibricus Linn., SW), drooping wild ryegrass (Elymus nutans Griseb, DW) and crested wheatgrass (Agropyron cristatum Gaertn., CW), three mixtures of these grasses (SB + DW, SB + SW + CW and SB + SW + DW + CW), and two annual monocultures of forage oats (FO) and annual ryegrass (Lolium annual, AR) in the alpine grasslands of Qinghai‐Tibet, China. Perennial grass monocultures of SW and DW and perennial grass mixtures of SB + SW + DW + CW and SB + SW + CW had higher forage yields, total revenues, output:input ratios and net profits than native grassland. These grasses and mixtures can be used to reseed native grassland and improve degraded grassland in the alpine region of the Qinghai‐Tibetan Plateau. Perennial grass mixtures can replace FO for more sustainable agricultural production systems as they are comparable in economic value and superior in ecological value to FO.     

Fructan,sucrose and related enzyme activities are preserved in timothy (Phleum pratense L.) during wilting

Timothy (Phleum pratense L.) is an important forage grass used for pasture, hay and silage in regions with cool and humid growth seasons. Harvesting conditions could reduce its nutritive value, particularly with extended wilting periods. To understand how daytime or night‐time wilting influences the nutritive value of timothy, this study investigated the metabolism of non‐structural carbohydrates, including fructan and starch, together with total soluble protein and amino acid patterns in timothy plants harvested at two maturity stages (heading and anthesis) and wilted under controlled conditions for 24 h at two temperatures (15°C, 20°C) and two light regimes (darkness, light) by simulating different wilting management practices. Correlation analysis with the whole dataset showed that soluble protein, glucose and starch contents declined in plant tissues concomitantly with water loss, while amino acid, sucrose and fructose contents increased. Transient increase in amino acid content suggests that the decrease in protein content was due to proteolysis during wilting. Sucrose and fructose contents generally increased in plant tissues harvested at anthesis and wilted in light whereas they were unaffected in plants wilted in darkness. Fructan content remained stable. Fructan exohydrolase (FEH) and soluble acid invertase (INV) activities were well preserved during the first 12 h of wilting and might facilitate the fermentation process at the beginning of ensiling by supplying fructose from fructans and hexoses from sucrose to the fermentive bacteria.