Effects of Lactobacillus buchneri isolated from tropical maize silage on fermentation and aerobic stability of maize and sugarcane silages

This study was aimed to perform a screening of Lactobacillus buchneri strains from maize silage and use them as inoculant in maize and sugarcane silages. In all, 151 lactic acid bacteria (LAB) strains were isolated from whole‐plant maize silage, and their identification was based on the sequence analysis of 16S rDNA. In total, 15 strains were categorized to the L. buchneri group and eight of these were selected based on growth rate and fermentation pattern. The selected strains were evaluated on fermentation and aerobic stability of maize and sugarcane silages. For maize, the inoculated silages had lower pH and higher LAB population, but lower acetic acid concentration in comparison with the untreated control silage. For sugarcane silage, the strains 56.1, 56.4 and 40788 resulted in highest dry‐matter (DM) content and lowest DM losses. However, only the strain 40788 showed lowest counts of yeasts and moulds. Sugarcane silages inoculated with the strains 56.9, 56.26 and the untreated control silage showed highest concentrations of lactic acid and ethanol, besides the great DM losses. Even so, for both crops, the aerobic stability was not affected by inoculation. After air exposure, all silages increased temperature and had high population of yeast and moulds. Nevertheless, the strains 56.1 and 56.4 are promising for use as a silage inoculant.     

Effectiveness of chopped lucerne hay as a moisture absorbent for low dry‐matter maize silage: Effluent reduction,fermentation quality and intake by sheep

This study determined effects of addition of lucerne hay (LH) as moisture absorbent on effluent reduction, fermentation and subsequent intake of maize (corn) silage by sheep. Treatments included maize forage ensiled without LH (LH0), with 50 g/kg LH (LH5) and with 100 g/kg LH (LH10) on a fresh weight basis. Silages were made in 150‐kg bags in triplicate. Upon opening, representative samples from each bag were taken twice weekly during a feeding trial and used for laboratory analyses in a completely randomized design. Silages were fed ad libitum to six ewes in a duplicated 3 × 3 Latin square design with 21‐day periods for intake and digestibility determination. Lucerne hay incorporation linearly increased DM, ash, water‐soluble carbohydrates, buffering capacity and pH of silages, while it linearly decreased ammonia nitrogen, acetic acid and ethanol concentrations (p < .05). Effluent volume linearly decreased from 33 ml/kg in LH0 to 0.8 ml/kg in LH10. Addition of LH resulted in a linear increase in intakes of organic matter and fibre in ewes, while digestibilities of these nutrients linearly decreased (p < .05). Lucerne hay addition improved fermentation parameters and resulted in increased intake of maize silage without having negative impact on aerobic stability.     

Effect of Lactobacillus buchneri 40788 on the fermentation,aerobic stability and nutritive value of maize silage

The effect of adding Lactobacillus buchneri 40788, a heterofermentative lactobacilli, to whole‐plant maize and its effect on fermentation and aerobic stability of the resulting silage were evaluated. Whole‐plant maize (380 g DM kg^–1 fresh weight) was ensiled in laboratory silos after the following treatments: untreated, L. buchneri 40788 at 1 × 10⁵, 2·5 × 10⁵, 5 × 10⁵, and 1 × 10⁶ colony forming units g^–1 of fresh forage or, a commercial inoculant containing homolactic acid bacteria, a single species of propionibacteria and enzymes. Addition of L. buchneri 40788 resulted in a decrease in lactic acid concentration but increased the concentration of acetic acid in silage and markedly decreased the numbers of yeasts present in the silage. All levels of L. buchneri 40788, increased the aerobic stability of silages but the effect was greatest for the two highest levels of inoculation. Treatment with the commercial inoculant had no effect on the fermentation or aerobic stability of silage. On‐farm treatment of maize silage with L. buchneri 40788, stored in a bag silo, resulted in changes in fermentation that were similar to those observed in laboratory silos. Treatment decreased the numbers of yeast in silage and increased aerobic stability (+25 h) of the silage when exposed to air. Treatment had no effect on the dry‐matter intake of silage fed to sheep. These results showed that treating silage with L. buchneri 40788 can increase the aerobic stability of maize silage in laboratory and farm silos.     

Efficacy of adding chemical and microbial additives to silage on beef cattle performance: Systematic review and meta-analysis

The effects of different additives on farm-scale silage quality and beef cattle performance are inconsistent. This study aimed to carry out a systematic review and meta-analysis to evaluate the efficacy of chemical and microbial additives to silage on beef cattle performance. Systematic searches were performed using databases and scientific journals, and 42 articles were selected. Data for all variables were grouped into subgroups according to the additive type. For dry matter intake and average daily gain, the data were also grouped by forage type due to greater comparison numbers. The treatment mean differences and 95% confidence intervals (p < 0.05) were analysed using a random-effects model. The use of homo- and heterofermentative microbial inoculant mixtures and chemical additives (Ch) increased the average daily gain of beef cattle fed maize/sorghum silage. Homofermentative microbial inoculant (Ho), Ch, and a mixture of microbial inoculant and chemical additives also increased the average daily gain of beef cattle fed temperate grasses. Only Ch increased dry matter intake. Ch increased feed efficiency, and Ch and Ho increased carcass weight. The evaluated additives improved the silage fermentation process mainly via pH and ammonia nitrogen reduction. Overall, this meta-analysis demonstrated that silage additives improved the ensiling process and beef cattle performance, with better results with Ch use. Due to the aerobic stability and microbiological profile analyses being carried out more in laboratory-scale silos, more studies are needed to determine these silage parameters after opening the silo at the farm scale.     

The effect of stage of perennial ryegrass maturity at harvesting, fermentation characteristics and concentrate supplementation, on the quality and intake of grass silage by beef cattle

Abstract Two experiments were carried out in consecutive years to examine the influence of cutting date and restricting fermentation by carboxylic acid treatment on the nutrient intake from grass silage by beef cattle. In year 1, four cutting dates during July and August after a primary growth harvest and, in year 2, five cutting dates of primary growth between mid‐May and early July were examined. Herbage was ensiled either untreated or treated with high levels of acid additive (‘Maxgrass’, mean 8·6 l t^?1). Ninety‐six (year 1) or forty‐eight (year 2) continental cross steers were used in partially balanced changeover design experiments with each silage type either unsupplemented or supplemented with 4·5 (year 1) or 5·5 (year 2) kg concentrates head^?1 d^?1. Silage digestibility declined significantly between initial and final harvest dates (P < 0·001), whereas silage dry‐matter (DM) and digestible energy (DE) intakes were significantly higher in the initial compared with final harvest dates in both years of the study (P < 0·01). Similarly, silage DM and DE intakes, and total DM intakes, of acid‐treated and unsupplemented silages were greater than those of untreated and concentrate supplemented silages, respectively (P < 0·001). The results indicate that earlier cutting dates, and addition of acid to herbage before ensiling, can increase silage DM intake by beef cattle.     

Effect of maturity stage at harvest on the ensilability of maize hybrids in the early and late FAO classes,grown in areas differing in yield potential

The aim of this study was to assess the effects of earliness (according to FAO class), maturity stage at harvest and environmental conditions on the ensilability of maize hybrids described by their fermentation products and by a fermentation quality index (FQI). Maize hybrids belonging to early (n = 14) and late (n = 15) FAO classes were grown in low, medium and high potential yield areas and harvested at an early (EH), medium (MH) and late maturity stage (LH), that is, at 1/3, 2/3 and 5 d after the 2/3 milk line stage, respectively, according to a split‐plot design. Upon harvest, each sample (n = 522) was analysed for dry matter (DM) and water‐soluble carbohydrates (WSC) before being ensiled in vacuum‐packed bags (n = 1,044). After 60 days of conservation, samples were analysed for DM and fermentation products. In the pre‐ensiling phase, DM was higher in early hybrids (p = .001), low yield areas (p < .001) and at LH maturity (p < .001), whereas WSC contents were higher in early hybrids (p < .001), medium yield areas (p < .001) and at EH maturity (p < .001). With regard to silages, early hybrids had a higher FQI (p < .001), which was highest in areas with a high yield potential (p < .01) and at EH maturity (p < .01). Late hybrids proved to be better suited for low yield areas compared with early hybrids (p < .01) and had a higher FQI at EH and MH than at LH maturity (p < .01).     

Aerobic stability of sugar-cane silage inoculated with tropical strains of lactic acid bacteria

Aerobic stability is an important feature in the evaluation of silages. The aims were to investigate the chemical and microbiological changes that occur in sugar-cane (Saccharum spp.) silage after aerobic exposure, to identify the major species of yeasts associated with the aerobic deterioration process and to select lactic acid bacteria (LAB) strains that can improve the aerobic stability of this silage. Fourteen wild LAB strains belonging to Lactobacillus plantarum, L. brevis and L. hilgardii were evaluated using experimental silos. Silage samples were collected at 0, 96 and 216 h after aerobic exposure to determinate the DM, WSC, pH, products of fermentation, to evaluate the silage temperatures and to identify yeast species associated with the aerobic deterioration of silage. The strains tested were able to modify the fermentative and chemical parameters and the diversity of yeasts species of silage after aerobic exposure. There was no association between the facultative or obligatory heterofermentative fermentation patterns and the increased aerobic stability of silage. Aerobic stability of sugar-cane silages was associated with high acetic acid and 1,2-propanediol concentrations. L. hilgardii UFLA SIL51 and UFLA SIL52 strains promoted an increase in aerobic stability of silage.     

Effects of Lactobacillus buchneri as a silage inoculant and as a probiotic on feed intake,apparent digestibility and ruminal fermentation and microbiology in wethers fed low‐dry‐matter whole‐crop maize silage

Lactobacillus buchneri was investigated as a silage inoculant and as a probiotic on feed intake, apparent digestibility, and ruminal fermentation and microbiology in wethers fed low‐dry‐matter (DM) whole‐crop maize silage. Maize forage (279 g/kg DM) was ensiled without inoculant (untreated) and with L. buchneri CNCM I‐4323 at 1 × 10⁵ cfu/g fresh forage (inoculated). Six cannulated wethers were arranged in a double 3 × 3 Latin square and assigned to one of three diets: (i) untreated maize silage (untreated), (ii) inoculated maize silage (inoculated), and (iii) untreated maize silage with a daily dose of L. buchneri (1 × 10⁷ cfu/g supplied silage) injected directly into the rumen (LB‐probiotic). Wethers fed the inoculated diet had a higher (p = .050) DM intake (1.30% body weight [BW]) than wethers fed untreated and LB‐probiotic diets (1.17% and 1.18% BW respectively). The relative proportion of Ruminococcus flavefaciens (proportion of total estimated rumen bacterial 16S rDNA) in the rumen of wethers fed inoculated and LB‐probiotic diets (both 0.42%) tended (p = .098) to be lower than in the untreated diet (0.83%). Lactobacillus buchneri as a silage inoculant or as a probiotic had little effect on the variables measured in wethers.     

Effects of defoliation on whole‐plant maize characteristics as forage and energy crop

Hail affects yield and quality of maize crops, and consequences also depend on the growth stage at which the injury occurred. Whole‐plant maize (WPM) silage is often used within the same farm for cattle feeding and biogas production. The present study aimed to verify the effects of hail damage, simulated by artificial defoliation, on yield and chemical and nutritional features, as well as on biochemical methane potential (BMP) of maize forage. In a randomized block design with three replicates, four defoliation levels (0%, 33%, 66% and 100% of leaf area removal respectively) have been applied at either the V12 (12th leaf), R1 (silking) or R3 (milk) stages for two consecutive years. WPM yield, chemical and nutritional features, and BMP were measured. Dry‐matter (DM) yield per hectare was progressively reduced (p < 0.001) with increasing levels of defoliation and with application at V12 in comparison with R1 or R3 (1.26 vs. 1.39 and 1.46 kg ha^?1 for V12 vs. R1 and R3; p < 0.003). Nutritive value and BMP per unit of product were less altered than dry‐matter yield per hectare by defoliation. Anticipating defoliation reduced net energy for lactation (5.26 vs. 5.46 MJ kg^?1 DM for V12 and R3 respectively; p = 0.02). Total defoliation resulted in an accumulation of nitrates (NO₃) compared to the other treatments (3.98 vs. 1.53 g NO₃ kg^?1 DM; p < 0.001). BMP was mainly reduced by early and complete defoliation. Equations were developed to estimate the effects of defoliation on yield, composition, and nutritive and energetic values of WPM.     

The effects of lactic acid bacteria on the fermentation,aerobic stability and nutritive value of maize silage

Maize was harvested at one‐third milk line (297 g kg^?1 DM) stage. All inoculants were applied at 1 × 10⁶ cfu g^?1 of fresh forage. After treatment, the chopped forages were ensiled in 1·5‐L anaerobic jars. Three jars per treatment were sampled on days 2, 4, 7, 12 and 90 after ensiling, for chemical and microbiological analysis. Homofermentative LAB‐inoculated silages had lower pH and higher lactate:acetate ratio (except for Lactobacillus plantarum/Pediococcus cerevisiae and L. plantarum/Propionibacterium acidipropionici) than the control and both heterofermentative LAB‐inoculated silages. Both L. buchneri inhibited yeast growth and CO₂ production during exposure of silage to air. The L. plantarum/P. cerevisiae, L. plantarum (Ecosyl) and L. plantarum/Enterococcus faecium‐inoculated silages had higher dry‐matter digestibility than the control and L. buchneri‐inoculated silages. Inoculants did not affect digestibility of neutral detergent fibre, except for L. buchneri (Biotal), organic matter nor ME content of silages. The LAB silage inoculants generally had a positive effect on maize silage characteristics in terms of lower pH and shifting fermentation toward lactate with homofermentative LAB or toward acetate with L. buchneri. The use of L. buchneri can improve the aerobic stability of maize silages by the inhibition of yeast activity.     

Effect of chitosan on the preservation quality of sugarcane silage

We aimed to evaluate the effects of chitosan and microbial inoculant addition to sugarcane silage fermentation, gas and effluent losses, chemical composition, in situ dry matter (DM), neutral detergent fibre (NDF) degradation and aerobic stability. A completely randomized design with four treatments (n = 40) was performed. It was arranged in a 2 × 2 factorial scheme with chitosan [0 and 6 g/kg of sugarcane DM—1.66 g/kg of natural matter (NM)] and microbial inoculant (0 and 8 mg/kg on NM). Each g of inoculant contained 3.9 × 10¹⁰ UFC/g of Pediococcus acidilactici and 3.75 × 10¹⁰ UFC/g of Propionibacterium acidicipropionici. The addition of microbial inoculant increased lactic acid concentration in silos treated with chitosan. Furthermore, chitosan increased pH and tended to increase acetic acid of silage. In contrast, the inoculant decreased pH and acetic acid, besides increasing ethanol concentration. As chitosan addition increased DM recovery, inoculant addition decreased it. Chitosan decreased NDF and acid detergent fibre (ADF) level and increased DM degradation, while inoculant decreased DM content, DM and NDF degradation. In addition, chitosan improved the aerobic stability only in non‐inoculated silos. Thus, chitosan has a positive effect on silage fermentation, reducing fermentative losses, and improving silage chemical composition and degradation. Conversely, the addition of microbial inoculant negatively affected silage DM recovery, chemical composition, and its association with chitosan decreased the aerobic stability when compared to the exclusive use of chitosan.     

Productivity of beef cattle grazing Brachiaria brizantha cv. Marandu with and without nitrogen fertilizer application or mixed pastures with the legume Desmodium ovalifolium

The use of forage legumes to contribute biologically fixed nitrogen (N) to pastures is an alternative to increase beef cattle production in tropical regions. The objective was to compare the impact of the introduction of a legume with that of N fertilizer application on forage and animal production in Brachiaria pastures. This two-year study assessed three pasture treatments: (1) mixed Marandu palisadegrass (Brachiaria brizantha [syn. Urochloa brizantha] cv. Marandu) and the legume “ovalifolium” (Desmodium ovalifolium) cv. Itabela (Mixed), (2) Marandu palisadegrass pastures with 150 kg N ha⁻¹ (Fertilized), and (3) Marandu palisadegrass without N fertilizer (Unfertilized). Rotational stocking with a variable stocking rate was used with a target herbage allowance of 1.0 kg forage kg body weight⁻¹. The pre-grazing green herbage mass was similar for Fertilized and Mixed pastures, with 54% and 63% more mass than Unfertilized pasture, respectively (p < .001). Cattle that grazed the fertilized pasture had the greatest average daily gain (ADG; p = .017). The stocking rate and liveweight gain per area were greatest for the Fertilized and Mixed pastures (p < .001 and p < .001, respectively). No differences between treatments were found for DM forage intake (p = .555). Organic matter digestibility was lowest (p < .001) for the Mixed pasture. The inclusion of the ovalifolium legume in the Marandu pasture had the same impact on beef cattle production as annual fertilization with 150 kg N ha⁻¹. The potential and environmental benefits of ovalifolium are discussed.     

Effects of treating low dry-matter grass with a bacterial inoculant on the intake and performance of beef cattle and studies on its mode of action

A randomized block design experiment involving thirty beef cattle (mean initial live weight 462 kg) was carried out to evaluate a bacterial inoculant based on a single strain of Lactobacillus plantarum as a silage additive and to provide further information in relation to its mode of action. Three herbages were harvested on 10 August 1989 using three double-chop forage harvesters from the first regrowth of a perennial ryegrass sward which had received 170 kg N, 25 kg P₂O₅, and 42 kg K₂O ha^?1. They received either no additive (silage C), formic acid at 2·91 (t grass)^?1(silage F) or the inoculant at 3·21 (t grass)^?1 (silage I). Mean dry-matter (DM), water-soluble carbohydrate and crude protein concentrations in the untreated herbages were 158g kg^?1, 88 g (kg DM)^? and 183g (kg DM)^?1 respectively. For silages C, F and I respectively, pH values were 4·01, 3·57 and 3·62; ammonia N concentrations 117, 55 and 77 g (kg total N)^?1; and butyrate concentrations 2·18, 0·50 and l·24g (kg DM)^?1. The silages were offered ad libitum and supplemented with 2·5 kg concentrates per head daily for 77 days. For treatments C, F and I, silage DM intakes were 6·59, 7·25 and 6·80 (s.e. 0·074)kg d^?1; metabolizable energy (ME) intakes 86,99 and 94 (s.e. 0·8) MJ d^?1; liveweight gains 0·90, 0·97 and 1·02(s.e.0·066) kg d^?1; carcass gains 541,656 and 680 (s.e. 34·0) g d^?1. Inoculant treatment increased DM (P < 0·01), organic matter (P < 0·01), crude fibre (P < 0·05), neutral detergent fibre (NDF) (P < 0·05) and energy (P < 0·05) digestibilities, the digestible organic matter concentration (P < 0·01) and the ME concentration (P < 0·05) of the total diets. Additive treatment altered rumen fermentation patterns but had little effect on the rumen degradability of silage DM, modified acid detergent (MAD) fibre, NDF or hemicellulose. It is concluded that treatment with the inoculant improved silage fermentation and increased digestibility, had little effect on silage DM intake but significantly increased carcass gain to a level similar to that sustained by a well-preserved formic acid-treated silage     

Effect of compaction,delayed sealing and aerobic exposure on forage choice and short‐term intake of maize silage by goats

Forage choice and intake by ruminants depend on various factors. This study aimed to determine the effects of compaction, delayed sealing and aerobic exposure on forage choice and short‐term dry‐matter intake (DMI) of maize silage by goats. Whole‐crop maize (277 g/kg dry matter [DM]) in 120‐L silos was compacted at either low (194 kg DM/m³) or high (234 kg DM/m³) density, and sealed immediately at day 0 or with a delay at day 2 or day 4 post‐filling, making a total of six treatments. After ensiling for at least 175 days, silages were exposed to air for 6 days. In 2‐day intervals, silages were sampled for chemical analyses and were vacuum‐stored for use in preference trials. During the experimental phase, each possible two‐way combination of the aerobically exposed silages (days 0, 2, 4 and 6 post‐opening) of the treatments and lucerne hay was offered as free choice to goats (n = 5) for 3 hr. Exposing silages to air for >4 days post‐opening caused strong avoidance and lowest intakes. Under the conditions of the study, aerobic exposure after ensiling had a more pronounced effect on silage preference and short‐time DMI than compaction and delayed sealing. Increasing fibre fractions, a deteriorating microbial status and poor silage sensory properties, probably caused by a combination of different fermentation products, can be considered for decrease in preference.     

Influence of maceration at cutting on lactic acid bacteria populations, silage fermentation and voluntary intake and digestibility of precision-chopped lucerne silage

Laboratory experiments with lucerne (Medicago sativa) have shown that maceration at cutting improves silage fermentation. Samples taken during wilting and after various ensiling periods were analysed for lactic acid bacteria (LAB) numbers and indices of silage fermentation. In Experiment 1, in which maceration was tested in unwilted and wilted lucerne, there was an additive effect of maceration and wilting on LAB numbers at ensiling, thus LAB numbers were approximately 108 colony-forming units (cfu) g^?1 fresh crop for wilted, macerated forage compared with 103 cfu g^?1 fresh crop for unwilted, unmacerated forage at ensiling. Initially, maceration reduced pH (P < 0·001) and increased lactic acid (unwilted comparison only; P < 0·001) and insoluble N (wilted comparison only; P < 0·001) concentrations. After 70 d ensiling, beneficial effects of maceration were associated only with the wilted silage. In Experiment 2, macerated lucerne was compared with unmacerated material, which was either ensiled after a wilting period of similar length or after wilting had proceeded to the same DM concentration as in the macerated forage. During wilting, LAB numbers were significantly higher in macerated than unmacerated forage (P < 0·05). This was also the case during the first 16 h of ensiling (P < 0·01). A decline in pH was observed earlier in macerated silage. Two days after ensiling, lactic acid concentration was higher in macerated silage (P < 0·05), but insoluble N concentration was not different. In a third experiment, unconditioned forage was compared with forages ensiled after regular conditioning or maceration. Although drying rate over 30 h was not influenced by degree of conditioning, LAB numbers during wilting increased with the degree of conditioning. In silages made from these treatments after 6 h wilting, there were no major effects on fermentation characteristics. In a fourth experiment, digestibility and voluntary intake of precision-chopped silage were measured in sheep and found not to be increased by maceration. It was concluded that maceration per se resulted in marginal improvements in fermentation; however, when maceration also increased DM concentration, fermentation was markedly improved. In these precision-chopped silages, maceration had no effect on intake or digestibility.     

Effects of additives on the fermentation and aerobic stability of grass silages and total mixed rations

Mown herbage of timothy–meadow fescue (dry matter 218 (LDM) or 539 (HDM) g kg^?1) was ensiled in laboratory silos to evaluate silage additives. For LDM silage, additives including formic acid (a blend of formic acid, sodium formate, propionic acid, benzoic acid, glycerol and another blend of formic acid and ammonium formate, both applied at 5 L t^?1) were able to restrict fermentation and thereby improve intake potential of the silage. Aerobic stability (AS) of total mixed ration (TMR) was also improved. LDM grass treated with homofermentative lactic acid bacteria (_hoLAB) resulted in silage containing lactic acid at 132 g kg^?1 DM, ammonium‐N <40 g kg^?1 total N, and pH < 3·8, and the AS was poor (<36 h). The treatment including heterofermentative strain (Lactobacillus brevis) produced more acetic acid and better AS than _hoLAB. Salt treatment (sodium benzoate, potassium sorbate, sodium nitrite) reduced pH compared to the Control treatment (3·89 vs. 4·24) and improved AS of TMR. The LDM Control silage had good AS, but the TMR based on it had poor AS. All additives were able to lower pH on HDM silages also, but other benefits of using additives were minimal. The treatment including L. brevis on HDM was able to improve AS of TMR.     

The effect of grazing versus cutting on dry matter production of multispecies and perennial ryegrass‐only swards

Dry matter (DM) production of multispecies swards compared to perennial ryegrass (Lolium perenne; PRG) swards under intensive grazing warrants investigation as it is relatively unknown. A 5 × 2 factorial experiment, with five sward types and two defoliation methods, was used to investigate the effect of grazing versus cutting on dry matter (DM) production of multispecies and PRG‐only swards. Five sward types were established namely: a PRG‐only sward, receiving 250 kg N ha^?1 year^?1 (PRG250), and a PRG‐only sward (PRG90), a two‐species sward with PRG and white clover (Trifolium repens; PRGWC), a six‐species sward (6S) and a nine‐species sward (9S), each receiving 90 kg N ha^?1 year^?1. Cutting plots measured 1.95 × 10 m and grazing plots measured 10 × 10 m. All plots were harvested concurrently every 21–30 days from April‐November for two years (2015 and 2016). A strip from the grazing plots was cut for DM yield determination prior to turning in cattle for grazing. There was an interaction between sward type and defoliation method (p < .01), whereby there was no effect of defoliation method on the PRG‐only swards, however, the annual DM production of PRGWC, 6S and 9S swards reduced under grazing compared to cutting (p < .001; on average 1,929 kg DM/ha lower). Multispecies swards had lower DM production under grazing compared to cutting, while the DM yield of PRG‐only swards was unaffected by defoliation method.     

Effect of type of underlay film on fermentation profile,nutritional quality and estimated loss of organic matter in the outer layer of whole‐plant maize ensiled in large bunker silos

Losses of organic matter in the outer layers of bunker silos covered with conventional polyethylene (PE) plastic can be substantial due to oxygen transmission through the plastic top‐covering film during the post‐ensiling storage period. The effect of two silo covering materials, oxygen barrier (OB) film (45 μm thickness) and clear PE film (50 μm thickness), as underlays to a white‐on‐black PE plastic top cover (120 μm thickness), was assessed in the outer layer of whole‐plant maize silage stored in three large bunker silos in the People's Republic of China. Samples of the crop at harvest and of silage from the upper 45 cm layer at 5 months post‐ensiling, prior to removal of silage for feed‐out, were analysed for DM, fermentation profile and chemical composition. Loss of OM was estimated from concentrations of ash in the crop at harvest and in the silage. Differences between underlay films in silage fermentation profile were small. Silage protected with OB underlay film had higher mean concentration of starch (p < .008) and higher mean NDF digestibility (p < .003) than silage under PE underlay film. Concentrations of ash were lower (p < .001) for silage covered with OB film than for PE film in all three trials. Mean estimated losses of OM were 170 g/kg for OB underlay film and 232 g/kg for PE underlay film (p < .001), and whole‐silo estimated net economic benefits to OB underlay film ranged from 0.17 to 0.74 US $ per tonne fresh crop ensiled.     

The effects of lactic acid bacteria strains isolated from various substrates on the fermentation quality of common vetch (Vicia sativa L.) in Tibet

Eight lactic acid bacteria (LAB) strains isolated from five naturally fermented silages of different ensilage materials on the Tibetan Plateau were characterized, and their effects on the silage quality of common vetch (Vicia sativa L.) were studied. These LAB isolates were evaluated using morphological, physiological and biochemical tests. The eight isolated strains and one commercial inoculant (Lactobacillus plantarum MTD‐1) were subsequently added to common vetch for ensiling 60 days. All the isolated strains (LW4, M1, WG27, O30, I2, LCG3, LCG9, CG35) could grow normally at 5–20°C, pH 3.5–6.0 and NaCl (3.0%, 6.5%), and they were identified as Lactobacillus plantarum and Pediococcus pentosaceus by sequencing 16S rDNA. All the LAB inoculants improved the silage quality of common vetch, indicated by significantly (p < .05) higher lactic acid (LA) contents and ratios of lactic acid to acetic acid (LA/AA), and significantly (p < .05) lower pH and ammonia nitrogen (NH₃–N) contents. Strain LCG3 performed best among all LAB inoculants, indicated by the highest (p < .05) LA content and ratio of LA/AA, and the lowest (p < .05) pH and NH₃–N content. Strain LCG3 is recommended as starter culture for common vetch silage.     

Production of beef cattle grazing on Brachiaria brizantha (Marandu grass)—Arachis pintoi (forage peanut cv. Belomonte) mixtures exceeded that on grass monocultures fertilized with 120 kg N/ha

Mixed grass/legume pastures are an alternative to grass monocultures for increased beef cattle production in tropical climates. The objective of this study was to evaluate the productivity of beef cattle grazing either a mixed pasture of Brachiaria brizantha cv. Marandu grass and Arachis pintoi (forage peanut) cv. Belomonte or a Marandu monoculture, under rotational stocking. Five trials were conducted over a period of nine years in north-eastern Brazil where the sward structure (forage, grass and legume mass) and animal performance were compared for a mixed Marandu grass/forage peanut pasture, and a Marandu grass monoculture with 120 kg N ha⁻¹ y⁻¹. Stocking rate was adjusted to maintain forage allowance at 4% body weight/day. A block design was used with four replicates, and warm and cool seasons within each trial were considered, using repeated measurements over time. In the warm season, the forage mass in the mixed pastures was 17% greater than in the monoculture (p = .049), and the stocking rate, average daily gain and liveweight gain per ha were 16.4%, 20.0% and 28.7% greater (p = .004, p < .001 and p < .001 respectively). The average daily gain showed a positive linear relationship with the legume proportion in the sward (p < .001). The mixed forage peanut/Marandu pasture sustained significantly greater beef cattle production (789 kg ha⁻¹ y⁻¹) compared to the N-fertilized grass monoculture (655 kg ha⁻¹ y⁻¹). Appropriately managed, mixed pastures of forage peanut/Brachiaria pastures are sustainable and have high potential for use in the humid tropics.