Effect of various bale treatments on physical quality and chemical composition of rhodes grass (Chloris gayana) hay

The effect of harvest season (winter vs. summer), moisture content at baling and bale mass on hay physical quality and chemical composition of two varieties of Rhodes grass ( Chloris gayana ) was studied during bale storage. Three moisture levels (15–20%, 20–25%, 25–30%) and three bale masses (13 kg, 18 kg, 24 kg, at an equal volume) were tested in varieties Pioneer and Alimba - the most common cultivars in the Arabian Gulf region. Variety Alimba has a rougher texture with more stems and fewer leaves. This caused significantly higher water retention and consequently higher bale temperatures. In summer, bale temperatures of Alimba stored at 25–30% moisture content and 24 kg bale mass averaged 37.7°C compared with 28·2°C in variety Pioneer. Lowest dry-matter (DM) content was 793 g kg⁻¹ and was recorded in the winter cut of variety Alimba baled at the upper moisture level (25–30%), whereas the highest was that of variety Pioneer. Lowest crude protein content was that of variety Pioneer (61 g kg DM⁻¹). Prolonged heat build-up of some bales caused dark-brown discoloration, and, although colour variations were significant, they were not large. There was no contribution of bale mass to changes in DM content, indicating that the selected levels of bale mass in the experiment were lower than those expected to cause significant effects on hay chemical composition and nutritive value. In general, it is recommended to store Rhodes grass hay at moistures up to 30% and even higher in the summer season in the case of variety Alimba. Higher moisture contents at baling could preserve hay quality by minimizing shattering of leaves excessively dried under the prevailing hay-making conditions, especially in the variety Pioneer.     

Cell wall degrading enzymes for silage. 1. The fermentation of enzyme-treated ryegrass in laboratory silos

The effects of two commercial cellulase/hemicellulase enzymes derived from Trichoderma reesei on silage fermentation were investigated in three laboratory-scale experiments. In Experiment 1, perennial ryegrass ( Lolium perenne ) was treated with enzyme A at the rates of 0, 0·125, 0·250, 0·500 and 0·750 cm³ kg^-1. In Experiment 2, Italian ryegrass ( Lolium multiflorum ) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm³ kg^-1 and with 85% formic acid (3·5 cm³ kg^-1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm³ kg^-1) and with 0·200 and 0·400 cm³ kg^-1 enzyme B which also contained glucose oxidase. All silages were well preserved. In general enzyme treatment reduced pH and the contents of ammonia nitrogen, neutral detergent fibre and acid detergent fibre, whereas the contents of water-soluble carbohydrates, acetic acid, lactic acid and ethanol were increased.     

Some changes associated with the field drying of lucerne and timothy

Lucerne (approximately 10% flowering, 270 g dry matter kg⁻¹) and timothy (boot stage, 310 g dry matter kg⁻¹) were harvested and allowed to wilt for a period of 52·5 h. During the early stages of wilting of lucerne there were increases in the proportion of leaf material (dry weight basis), as well as increases in total available carbohydrate and water soluble carbohydrate concentrations. Approximately 50% of the leaf material in lucerne and in timothy was lost after a drying period of 52·5 h and after tedding and raking operations prior to baling of the hay. This resulted in considerable reduction in the protein content of both lucerne and timothy.     

Drying and physical characteristics of matted ryegrass

Fresh ryegrass and lucerne were macerated and compressed into thin mats over a 4-week period at two yield levels. The mats were left lo dry outside during the day. and inside overnight, and compared with unconditioned crops. Under a low swath yield of 4 t DM ha⁻¹, mats required 0·7-1·4 mm pan evaporation lo reach 70% moisture, suitable for wilted silage, compared with 1·8-3·8 mm pan evaporation for unconditioned crops. On an average non-rainy day. mats were ready to harvest as wilted silage after 2–5 h, whereas the unconditioned crop required between 6 h and 36 h of wilting. With a high swath yield of 8 t DM ha⁻¹, mats required 1·4-3·0 mm pan evaporation to reach 70% moisture compared with 2·4-5·1 mm for unconditioned windrows. Low-yield mats reached 20% moisture, suitable for hay, in 2 d of drying, after 4·5-5·3 mm of pan evaporation. The thickness and cohesion of the mats were measured to assess their sensitivity to mechanical handling. The effect of controlled rainfall on mats was also investigated. Since mat making was most effective in low-yield crops, it could become a useful complement to low-input, extensive forage production. Mat making could eliminate most silage effluent losses; it could re introduce haymaking of ryegrass as a viable system under certain circumstances.     

Cell wall degrading enzymes for silage. 2. Aerobic stability of enzyme-treated laboratory silages

The effects of two commercial cellulase/hemicellulase enzymes derived from Trichoderma reesei on silage fermentation and aerobic stability were investigated in three laboratory-scale experiments. In Experiment 1, perennial ryegrass ( Lolium perenne ) was treated with enzyme A at the rates of 0. 0·125, 0·250, 0·500 and 0·750 cm³ kg^-1. In Experiment 2, Italian ryegrass ( Lolium multiflorum ) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm³ kg^-1 and with 85% formic acid (3·5 cm³ kg^-1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm³ kg^-1) and with 0·200 and 0·400 cm³ kg^-1 enzyme B which also contained glucose oxidase. All silages were well preserved. Aerobic deterioration was related to numbers of lactate assimilating yeasts. In Experiment 1, all silages were stable over a 4-day period. In Experiment 2, enzyme A treatment delayed the temperature rise compared with the untreated control ( P <0·05), whereas the formic acid-treated silage was stable. In Experiment 3, the temperature rise in the silage treated with the higher level of enzyme B occurred one day later than in the other silages ( P <0·05).     

The effect of addition of sugar and inoculation with two commercial inoculants on the fermentation of lucerne silage in laboratory silos

Lucerne (DM 236 g kg^-1, WSC 49 g (kg DM)^-1) was ensiled in test-tube silos with or without either glucose or fructose and with or without one of two commercial inoculants. The WSC content of the forage as ensiled was too low to obtain a well preserved untreated silage. By day 4 the pH values of the silages with added sugar or inoculant were significantly lower (P< 0·001) than the control silage. A satisfactory fermentation was attained only in the silages to which sugar and an inoculant had been added. These silages had a lower pH, more protein-N (P< 0·001), less ammonia-N (P<0·001), a faster increase in counts of lactic acid bacteria, and decrease in counts of coliforms than the other silages. Homo-fermentative lactic acid bacteria dominated the fermentation in the inoculated silages while leuconostocs dominated the early stages of fermentation in the control silages. The results indicate that if there is insufficient sugar in the original crop, then the bacteria in an inoculant will not be able to produce enough lactic acid to lower the pH to an acceptable level. This has important implications for the ensilage of lucerne and other highly buffered low sugar crops.     

Silage and milk production: a comparison between long, chopped and ground hays as supplements to silage of high digestibility

Grass silage made in May from S24 perennial ryegrass had a DM concentration of 262 g kg^-1 and an in vitro D-value of 0·698, and was given ad libitum to twelve Ayrshire cows in a 16-week feeding experiment. In addition supplements of hay with a mean in vitro D-value of 0·603 were offered in one of three forms—long, chopped (12·1 mm) or ground (0·80 modulus of fineness) and cubed—and of concentrates given at either 2 or 4 kg per 10 kg milk. Hay averaged 18·2% of total forage DM intake with mean daily intakes of 1·28, 1·22 and 2·26 kg DM per cow in the long, short and ground forms respectively. The highest daily intakes of forage, i.e. silage plus hay, occurred on the ground hay treatments, with values of 10·24 and 9·25 kg DM per cow on the 2 and 4 kg concentrate treatments respectively. The mean daily milk yields were 18·2,18·2 and 19·2 kg per cow on the long, short and ground hay treatments respectively but the increase in yield with the ground hay was only significant at the low level of concentrate intake. The hay treatments had small and non-significant effects on milk composition. It is concluded that ground hay was superior to either long or chopped hay as a supplement for silage, but the small advantages depended on the level of concentrate intake.     

Influence of growth stage and season on the energy value of fresh herbage. 2. Relationships between digestibility and metabolizable energy content and various laboratory measurements

This paper gives details of a study which has examined the effect of herbage growth type and season on the relationships of digestible organic matter in the dry matter (DOMD) and metabolizable energy (ME) contents measured in vivo to various laboratory measurements including three in vitro estimates of DOMD based on rumen fluid pepsin (RFP), pepsin cellulase (PC) or neutral detergent cellulase (NCD). Seventy herbages harvested over two years and comprising 32 spring primary growths, 14 summer regrowths and 24 autumn growths were used.
For DOMD in vivo , significantly different regression relationships were required for spring and autumn-harvested herbage. Equations based on PC were:
Spring herbage: DOMD (g kg^-1 DM) = 436 + 0·501 PC (g kg^-1 DM) ²= 76·7%; r.s.d. = 25·4
Autumn herbage: DOMD (g kg^-1 DM) = 594 + 0·195 PC (g kg^-1 DM) ²= 15·5%; r.s.d. = 23·1
For autumn herbages there were no significant relationships with ME. As with DOMD in vivo the PC method was shown to provide the most accurate relationship with ME concentration of spring herbage. The relationship was:
ME (MJ kg^-1 DM) = 6·16 + 0·0094 PC (g kg^-1 DM) ²= 69·8%; r.s.d. = 0·57
For both DOMD and ME the relationships for spring herbage based on PC were the only ones which did not differ significantly from those of an earlier study.
It is concluded that even where significant relationships for summer and autumn herbages were developed, the predictors accounted for substantially less of the variability than in spring herbages. This appeared to be largely due to reduced range in the DOMD and ME content in summer and autumn herbages.     

Effects of formic acid on silage fermentation, digestibility, intake and performance of young cattle

Data from twenty-two comparisons carried out at ADAS Experimental Husbandary Farms are used to compare untreated and formic acid-treated silages. Additive treatment led to an improved fermentation in some crops, particularly those of low DM concentration (<262 g kg^-1). Where this occurred there were associated benefits in silage digestibility (+0·234 units), intake (+16%) and the growth rate of young cattle (+0·28 kg d^-1). Where the fermentation of the untreated silage was good, both digestibility and animal performance associated with treated and untreated silages were similar. It is suggested that the justification for using formic acid in a commercial situation is thus restricted to occasions where the untreated crop would be liable to develop a clostridial fermentation. These may be when crops contain less than 35 g water-soluble carbohydrate kg^-1.     

A COMPARISON OF NUTRIENT LOSSES IN BALED HAY MADE FROM FORAGE-HARVESTED, CRIMPED OR TEDDED SWARDS WITH THOSE IN BARN-DRYING

Two experiments were conducted to study the effect on nutrient loss and feeding value of making hay by different means, using a barn-drier, a forage-harvester, a crimper and conventional tedding. Both forage-harvesting and crimping of the herbage significantly increased the rate of drying, compared with tedding alone. In Exp. 2 this effect enabled the crimped and forage-harvested hays to be baled for storage 3 days earlier than the tedded hay. The use of the forage-harvester significantly reduced the yield of herbage compared with conventional mowing. Nutrient losses from cutting until storage were highest for the forage-harvested hays, the loss of dry matter between cutting and storage in the forage-harvested hays being 39·9 and 19·3%, respectively, in Expt 1 and 2 with corresponding losses in the conventionally made hays of 7·1% and 9·3%. Crimping the hay resulted in higher nutrient losses than tedding. In Expt 2 there was a loss of dry matter of 17·5% in the conventionally made hay during an 18-week storage period, compared with 3·6% in barn-dried hay, 10·8% in forage-harvested hay and 8·8% in crimped hay.
In Expt 2, in which digestibility determinations were made, conservation decreased the total digestible nutrients and starch equivalent in all treatments. The use of the barn-drier gave the most efficient conservation of total digestible nutrients, followed by the crimped, forage-harvested and conventional treatments in that order. The starch equivalent values of hays made from the same sward were 43·0 when barn-dried, 39·8 when crimped, 38·6 after forage-harvesting and 31·6 after tedding.     

The effect of propionic acid on the storage losses of hay

Storage losses in moist hay treated with propionic acid were compared with those occurring in untreated moist hay in two experiments and with field-cured hay in three experiments. Dry matter losses in treated hays ranged from 41 to 8.6% and from 1.7 to 12.6% in untreated hays. Digestible organic matter losses in both treated and untreated hays were generally greater than dry matter losses. Only in one experiment did propionic acid application significantly reduce nutrient losses in moist hays. Nutrient losses, and water-soluble carbohydrate losses in particular, were shown to be correlated with maximum and cumulative bale temperatures during storage in two of the experiments. The rise in hale temperatures during storage was reduced in all three experiments, to a greater or lesser extent, by application of the additive. Loss of propionic acid from the hay during and after application was very large. In the three experiments 86.2, 85.3 and 85.6% of the acid applied was lost by the end of the storage period. Acid distribution studies indicated that variation in acid concentration within bales was as great as between bales. It was concluded that more research is needed into applicator design and position on the baler and into alternative application methods if the benefits of propionic acid as a moist hay preservative are to be fully exploited.     

Silage and milk production: comparisons between hays of different digestibilities as silage supplements

In three separate feeding experiments using a total of thirty individually-housed Ayrshire cows three silages made from perennial ryegrass were given ad libitum together with supplements of four different hays in the long form. The in vitro D-values of the silages ranged from 0·298 to 0·283, and the hays from 0·280 to 0·200. The daily intake of hay DM varied from 0·2 to 4·2 kg per cow and was given either without or with a daily maximum of 2·2 kg concentrate DM containing 379–527 g CP per kg DM. On average, 1 kg hay DM decreased silage intake by 0·24 kg DM with a range of 0·21–1·20 kg. The hay supplements had only small and non-significant effects on total DM intake, milk yield and milk composition, but increased the daily intake of drinking water. In three behavioural studies, the eating and ruminating times expressed as min per kg DM did not differ significantly between the various supplement treatments. It is concluded that hay has only a marginal value as a supplement for grass silage, although the hay could serve as a useful 'buffer' feed if the amount of silage was limited.     

Fibrolytic enzymes and a ferulic acid esterase‐producing bacterial additive applied to alfalfa hay at baling: effects on fibre digestibility,chemical composition and conservation characteristics

This study evaluated the effect of two fibrolytic enzyme products, applied at baling, on the chemical composition and digestibility of alfalfa hay. Three replicate bales of alfalfa hay (82% dry matter) were produced with the application of one of five treatments including an untreated control and one of two fibrolytic enzyme products (DYC and ECO), either applied alone or in combination with a ferulic acid esterase‐producing bacterial additive. The enzyme products were applied on the basis of endoglucanase activity. The neutral detergent fibre (NDF) concentration and accumulated temperature after storage of hay produced using DYC‐ or ECO‐based treatments were greater (P < 0·05) than untreated hay, except for hay bales produced using ECO alone. Bales produced using ECO‐based treatments had a greater (P < 0·05) in vitro NDF digestibility compared with untreated bales. The application of fibrolytic enzymes at baling may potentially improve NDF digestibility without negatively affecting chemical composition or increasing aerobic deterioration. However, the effects of fibrolytic enzymes varied depending on the product applied. Combining ferulic acid esterase‐producing bacterial additives with fibrolytic enzymes did not improve the nutritive value of hay after storage.     

Influence of bacterial inoculant and substrate addition to lucerne ensiled at different dry matter contents

Field-wilted lucerne was chopped with a forage harvester at 33 ± 1·5, 43 ± 2·0 and 54 ± 1·8% dry matter, treated and ensiled in laboratory silos during four cuttings in each of two years. Treatments were control (C), sugar addition at 2% of fresh weight (S), inoculum applied at 3 × 10⁵ bacteria g⁻¹ herbage (I), and sugar and inoculum combined (IS). Duplicate silos were opened and analysed after 1, 2, 3, (4 or 5), 7, 14 and 60 d of fermentation. The initial rate of proteolysis of lucerne protein decreased with increasing dry matter (DM) content of the lucerne, and was not influenced by the year, cutting or silage treatment. Inoculation increased ( P <0·05) the rate of pH decline for all silage dry matters, and shortened the lag time prior to pH decline with 33 and 43% dry matter silages. Sugar addition had no effect on rate of pH decline or lag time. Inoculation and sugar addition both lowered final pH, acetic acid, ammonia (NH₃), free amino acids (FAA) and soluble non-protein N (NPN) in silages ( P <0·01) and increased lactic acid content with 33 and 43% dry matter silages. Only inoculation was beneficial at 54% DM with no difference between I and IS. The influence of forage characteristics (epiphytic lactic acid bacteria, buffer capacity and sugar:buffer capacity ratio) on treatment effectiveness varied with dry matter content.     

Impact of Pediococcus pentosaceus and Pichia anomala in combination with chitinase on the preservation of high‐moisture alfalfa hay

This study assessed the effects of applying Pediococcus pentosaceus (PED) or Pichia anomala (PIC) in combination with chitinase (CH) on the conservation characteristics and rumen digestibility of large round‐bale high‐moisture alfalfa hay (HMH). Alfalfa was wilted in the field to 23%–27% moisture and baled without (Control) or with PED + CH, PIC + CH and propionic acid (PA). The study was repeated yearly from 2012 to 2014. The PED + CH‐treated HMH had the numerically lowest high degree day (bale internal temperature >30°C) in all 3 years, which was less (p < .05) than Control HMH and PA in 2012. Treatments had no effect on pH, but mixed effects on chemical and microbial compositions across 3 years. The PED + CH treatment had the highest water‐soluble carbohydrate (WSC) content (p < .05) in 2012 and 2014, whereas PA treatment had the lowest (p < .05) WSC in these years. Total bacteria were decreased (p < .001) by PIC + CH and PED + CH in 2012 only. The PED + CH treatment had greater (p < .01) soluble fraction of dry matter (DM) than Control HMH and PA in both 2012 and 2014, but treatments did not affect the potential degradable fraction of DM. The PED + CH and PIC + CH treatments increased (p < .01) in situ neutral detergent fibre digestibility after 6, 24 and 96 hr of ruminal incubation in 2012 but not in 2014. Combinations of P. pentosaceus or P. anomala with chitinase have potential as high‐moisture hay inoculants to reduce microbial spoilage and to increase fibre digestibility.     

The influence of weather on the effectiveness of mechanical and chemical conditioning on drying rate of lucerne hay

Field drying experiments in summer and winter compared the drying rate of lucerne hay cut with a rotary disc mower and mower-conditioner, with or without 300 1 ha⁻¹ of 2% aqueous potassium carbonate solution sprayed at cutting. Local farm practice was followed in cutting, raking and drying. Statistical analysis showed significant treatment differences in both summer and winter experiments. Mechanical-cum-chemical conditioning treatment provided the greatest field drying rate, followed by chemical conditioning alone, mechanical conditioning alone and non-conditioned luceme, respectively. The effectiveness of mechanical and chemical conditioning treatments was greater in summer than in winter. Under good S.E. Queensland summer conditions, mechanical-cum-chemical conditioning would allow hay to be cut and baled on the same day, but at least 4 days were required under cool winter weather conditions.     

Fermentation and nutritive value of Zea mays and lucerne forage ensiled with added rolled barley

The effect of adding rolled barley on the ensiling characteristics and nutritive value of lucerne and corn ( Zea mays ) forage was studied using 19-1 plastic mini-silos. Other factors evaluated with lucerne were the effect of wilting and added lactic acid bacteria. Rolled barley was added at rates of 0, 50, 100 and 150gkg⁻¹ (wet weight) to lucerne or corn forage. Lucerne was ensiled at 170–330 g kg⁻¹ dry matter (DM) and lactic acid bacteria were applied at 10⁵g⁻¹ wet forage. Addition of rolled barley consistently improved the fermentation of lucerne by lowering the pH and decreasing the concentration of acetate and ammonia nitrogen. Wilting of lucerne had variable effects on fermentation in two experiments. The addition of lactic acid bacteria improved fermentation by decreasing the concentrations of acetate and ammonia nitrogen, improved the nutritive value by increasing the in vitro dry matter digestibility (IVDMD), and was associated with decreased amounts of lactic acid. Corn was ensiled at 250 g kg⁻¹ DM, and added rolled barley had little effect on the fermentation of corn silage. The digestibility of all silages determined in vitro was improved by the addition of rolled barley.     

Comparison of lucerne silage and ventilated hay in maize silage-based rations for dairy cows for the production of milk destined for Grana cheese

Three experiments were carried out to study the effects of feeding lucerne silage (wilted to give different dry-matter (DM) contents) and ventilated hay to dairy cows on milk production, milk quality, milk-renneting properties, clostridial spore content and the quality of cheese prepared from the milk. The lucerne, cut at vegetative or early-bud stages of maturity, was harvested from alternate windrows and conserved as silage or artificially dried hay. The lucerne was wilted until it reached different DM contents of 550, 360 and 432 g kg^–1 in the three experiments, harvested, chopped with a self-loading forage wagon and ensiled in low and narrow clamps made up of transferable prefabricated walls. The organic acid content, pH, yeast and mould counts of the lucerne silage suggested that there was no aerobic deterioration. In each experiment, fifty Italian Friesian lactating cows were divided into two groups and fed two maize silage-based rations for 6 weeks, which only differed in the lucerne forage [silage (S) vs. ventilated hay (H)], in a cross-over experimental design. The lucerne in the rations represented 35%, 23% and 24% of the DM of the rations for the three experiments. The microbiological profiles of the ration were influenced more by the maize silage than by the lucerne silage. Individual daily DM intakes were similar for the two treatments in Experiments 1 and 3 (on average 18·7 kg in Experiment 1 and 20·3 kg in Experiment 3) and slightly lower for S cows in comparison to H cows in Experiment 2 (18·0 vs. 19·0 kg). Milk yields of S and H cows were 21·0 and 20·8, 20·0 and 20·6 (P < 0·01), and 28·4 and 27·9 kg d^–1 in Experiments 1, 2 and 3 respectively. Milk composition was similar for all the experiments for the two treatments, except that the protein content was lower and the fat content was higher in the silage treatment than in the hay. The renneting properties and microbiology of the milk were not influenced by the introduction of lucerne silage into the rations, although the season in which it was consumed had a greater effect on the microbiological content, in terms of standard bacterial counts, proteolytic, coli and lactic acid bacteria, and clostridia spores. The clostridial spore counts were always very low (< 400 per litre), thus fulfilling the requirements for top-quality milk for Grana cheese production. In the third experiment, the quality of Grana Padano cheese produced was examined, and no differences between treatments were observed after 12 months of maturation. These results show that lucerne silage can be included in the ration of dairy cows instead of ventilated lucerne hay, which is considered to be the top-quality hay available for the production of milk destined for Grana cheese, without any negative effects on milk and cheese quality.     

The chemical composition, digestibility and energy value of fermented and urea-treated whole crop wheat harvested at three stages of maturity

The metabolizable energy (ME) content, digestibility in vivo and chemical composition of fermented and urea-treated whole crop wheat (WCW) forage harvested were measured at different maturities. Over 2 years, twenty-four wheat forages (cv. Slepjner, Hussar and Cadenza) were harvested at 376, 516 and 632 g dry matter (DM) kg⁻¹ in Year 1 and 341, 467 and 544 g DM kg⁻¹ in Year 2 (Cuts 1, 2 and 3 respectively). Forages were conserved in 200−-ι barrels with or without a formic acid-based additive and with urea in Cuts 2 and 3 (20 or 40 g kg⁻¹ DM). Chemical compositions, digestibility in vivo and energy losses in faeces, urine and methane were measured in wethers fed 12 g DM kg⁻¹ live weight. Respective ranges in pH, crude protein, water-soluble carbohydrates, starch and neutral detergent fibre plus amylase (NDFA) contents were 3·8–8·5, 89–394, 2–43, 23–424 and 306–655 g kg⁻¹ DM. ME content, digestible organic matter content (DOMD) and digestibilities of starch and NDFA ranged between 8·4 and 15·7 MJ kg⁻¹ DM, 558 and 708 g kg⁻¹ DM, 0·901 and 0·999 and 0·362 and 0·693 respectively. Predicted methane energy losses were poorly correlated with measured values ( r ² < 0·45) in both years, but this accounted for less than 0.1 MJ ME kg⁻¹ DM. Significant ( P < 0.05) effects of maturity on the ME/DOMD ratio were observed and ascribed to differences in the extent of fermentation. Therefore, treatment application and maturity exert considerable influence on the ME content of WCW.     

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

First and second harvests of lucerne (Medicago sativa L.), perennial ryegrass (Lolium perenne L.) and a lucerne–perennial ryegrass mixture [80 or 144 g kg^?1 dry matter (DM) of ryegrass] at the first and second harvests were cut and conditioned, wilted to 500 or 700 g DM kg^?1 then baled and stretch‐wrapped for silage on the same dates. Lucerne bales were denser (411 kg m^?3) than bales of perennial ryegrass (331 kg m^?3) (P < 0·05). After an 8‐month storage period, silage made from high DM‐content forage had a higher concentration of neutral‐detergent fibre (NDF) and was less digestible than that made from low DM‐content forage. Daily DM intakes by beef steers, when the silages of the second harvest were fed ad libitum, were 31·2, 31·2 and 22·3 g kg^?1 live weight for lucerne, lucerne–perennial ryegrass mixture and perennial ryegrass silages, respectively (P < 0·01), when the herbage had been wilted to 500 g kg^?1. In vivo digestibility of NDF in the lucerne–perennial ryegrass mixture silage (0·587) was significantly lower than that of perennial ryegrass silage (0·763) but higher than lucerne silage (0·518). Higher intakes of baled lucerne silage tended to offset its lower digestibility values. Lucerne–perennial ryegrass mixture silage had a higher DM and NDF digestibility than lucerne silage, indicating perhaps the presence of associative effects.