Silages containing bioactive forage legumes: a promising protein‐rich feed source for growing lambs

Forage legumes that contain secondary compounds are considered to be less susceptible to proteolysis than other legumes, with improved silage quality and possibly improved animal performance. This was investigated feeding five groups of growing lambs for 10 weeks, five silages composed of pure timothy (T; Phleum pratense), mixtures of T with red clover (Trifolium pratense; T‐RC, 50/50 on DM basis), sainfoin (Onobrychis viciifolia; T‐SF), or both (T‐RC‐SF, 50/25/25), or a mixture of the two legumes (RC‐SF). Including SF and/or RC in silages improved silage fermentation as shown by higher lactic acid and lower soluble N and NH₃ contents than in T silage. Voluntary intakes were higher with all the RC‐containing silages than with T and T‐SF. The T‐SF silage had the lowest, and RC‐containing silages the highest average values for daily gain, feed conversion efficiency, live weight and carcass weight. The differing effects of these silages cannot be totally explained by differences in their nutritive value and so may be due to their bioactive compounds impacting differently on feeding motivation and digestive efficiency. These results suggest that including RC in silages is a promising strategy to combine improved animal performance with reduced environmental pressure.     

Voluntary intake,digestibility and nitrogen utilization by sheep fed ensiled forage legumes

An experiment was conducted to compare the nutritive value of a range of ensiled forage legumes. Silages were prepared from late second‐cut lotus (Lotus corniculatus), first‐cut sainfoin (Onobrychis viciifolia) and both early and late second‐cut red clover (Trifolium pratense) and lucerne (Medicago sativa). Each experimental silage was offered to six Suffolk‐cross wether lambs, aged 10 months, housed in metabolism crates. Voluntary intakes of dry matter ranged from 71 to 81 g kg^?1 liveweight^0·75 d^?1. Voluntary intakes were similar on the lotus, sainfoin and late‐cut red clover silages, but the voluntary intake on the lotus silage was significantly higher than that on the lucerne silages and early‐cut red clover silage. Digestibility of organic matter in the dry matter was highest for the lotus silage (0·650), and lowest for the sainfoin silage (0·527). Although most of the N in the sainfoin silage appeared to be in an indigestible form, N digestibility was approximately 0·70 for the other legume silages. The highest loss of N in urine, 0·75 of N intake, was recorded for lambs offered the lucerne silage. Differences in N intake, N loss in faeces and N loss in urine led to statistically significant differences in the amount of N retained, with the highest and lowest N balances recorded for the lotus (16 g N d^?1) and sainfoin (?2 g N d^?1) silages respectively. The results confirm that these high protein forages have high intake potential. While low N digestibility appears to limit the nutritional value of sainfoin, further research could formulate feeding strategies that improve the efficiency with which the protein from red clover, lucerne and lotus is utilized.     

Effects of tropical legume silages on intake,digestibility and performance in large and small ruminants: A review

A meta‐analysis was performed to determine the effects of feeding ruminants with tropical legume silages on intake, digestibility and performance using a data set with 218 treatments (162 containing legumes, 56 without legumes) from 62 trials. First, a regression analysis was performed for diets containing legumes. Dry‐matter intake (DMI) and digestibility decreased with increasing legume proportion, with greater effects on large compared with small ruminants. Milk yield (MY) by dairy cows was not affected by legumes. Average daily gain (ADG) by cattle was maximized with legume silage inclusion between 200 and 400 g/kg DM, but no effect appeared for small ruminants. A second analysis compared diets without legumes with diets with medium (101–400 g/kg DM) and high (401–800 g/kg DM) legume inclusion. There were no differences in DMI, MY and ADG between the medium inclusion and without legumes, but all these parameters decreased with high inclusion. Digestibility was lower in diets with legume silages than in diets without legumes, regardless of the inclusion level. Feed conversion efficiency (FCE) was highest in diets with medium inclusion and lowest with high legume inclusion. While high legume inclusion negatively affected performance, including legume silages up to 400 g/kg DM seems to enhance or at least maintain MY, ADG and FCE, despite lower intake and digestibility. The reasons for such apparent paradox remain unclear. Well‐designed studies focusing on, e.g. microbial protein synthesis, energy metabolism, protein/carbohydrates characteristics, are required to better understand the effects of tropical legumes silages on nutrients’ utilization.     

Modelling feed intake and milk yield responses to different grass ley harvesting strategies

A meta‐analysis of feeding trials using grass silages was conducted to predict production responses for dairy cows fed grass silage. They were divided into two subsets: 69 diets from 11 studies were used for comparison of silages made from primary growth and regrowth grass (harvesting subset), and another 157 diets from 24 studies were used for comparison of digestibility influenced by the maturity of grass ensiled (D‐value, digestible organic matter in dry matter) (maturity subset). The minimum prerequisite for an experiment to be included in the data set was that milk production, feed intake, silage characteristics and concentrate ingredients were reported. Both subsets were analysed using the mixed model procedures of SAS. The mean response in dry‐matter intake (DMI) and silage DMI to improved silage D‐value was 0.0175 and 0.0161 kg per unit D‐value (g/kg DM) respectively. The average increase in milk and energy‐corrected milk yield was 0.30 and 0.37 kg per 10‐unit increase in silage D‐value respectively. Milk protein concentration increased, and fat concentration tended to increase with enhanced silage D‐value. Each 10‐unit increase in D‐value reduced milk yield by 0.092 kg at a given dietary metabolizable energy intake (MEI), suggesting that the ME concentration of high D‐value silages was overestimated. Cows fed regrowth silage produced 0.55 kg/day more energy‐corrected milk than those fed primary growth silage at a given dietary MEI. The prediction models can be used to improve ration formulation systems or incorporated into economic models for optimizing milk production in various farming systems.     

Apparent digestibility and nitrogen utilization of diets based on maize silage harvested at three stages of maturity and fed to steers

Advancing maize crop maturity is associated with changes in ear‐to‐stover ratio which may have consequences for the digestibility of the ensiled crop. The apparent digestibility and nitrogen retention of three diets (Early, Mid and Late) containing maize silages made from maize of advancing harvest date [dry matter (DM) contents of the maize silages were 273, 314 and 367 g kg^?1 for the silages in the Early, Mid and Late diets respectively], together with a protein supplement offered in sufficient quantities to make the diets isonitrogenous, were measured in six Holstein–Friesian steers in an incomplete Latin square design with four periods. Dry‐matter intake of maize silage tended to be least for the Early diet and greatest for the Medium diet (P = 0·182). Apparent digestibility of DM and organic matter did not differ between diets. Apparent digestibility of energy was lowest in the Late diet (P = 0·057) and the metabolizable energy concentrations of the three silages were calculated as 11·0, 11·1 and 10·6 MJ kg^?1 DM for the Early, Medium and Late diets respectively (P = 0·068). No differences were detected between diets in starch digestibility but the number of undamaged grains present in the faeces of animals fed the Late diet was significantly higher than with the Early and Mid diets (P = 0·006). The apparent digestibility of neutral‐detergent fibre of the diets reduced significantly as silage DM content increased (P = 0·012) with a similar trend for the apparent digestibility of acid‐detergent fibre (P = 0·078). Apparent digestibility of nitrogen (N) was similar for the Early and Mid diets, both being greater than the Late diet (P = 0·035). Nitrogen retention did not differ between diets. It was concluded that delaying harvest until the DM content is above 300 g kg^?1 can negatively affect the nutritive value of maize silage in the UK.     

Grass silage as a basic feed for store lambs. 1. Effect of wilting, chop length and stage of maturity of grass silage on intake and performance of store lambs

Two experiments were carried out with grass silages cut at a leafy (Experiment 1) and a more mature (Experiment 2) stage of growth to evaluate the effect of wilting and chop length on silage intake and performance of store lambs. In each experiment, the herbage was cut with a rotary mower and was either ensiled within 24 h as unwilled silage (U) or wilted for 1–3 d (W). Each silage type was harvested with either a double-chop harvester (D) or a precision-chop harvester (P). All silages were treated with formic acid at 3 1 t^?1 and were well preserved. The silages were fed ad libitum to Suffolk crossbred store lambs (twenty-four lambs per treatment) without any supplement over a period of 8 or 9 weeks. Wilting of the silages had little effect on silage intake (797 vs. 809g dry matter (DM) d^?1) or on lamb performance in Experiment 1. In Experiment 2, wilting of the D silage increased silage DM intake (589 vs. 534 g DM d^?1; +10%) and reduced the extent of liveweight losses. Wilting of the P silage reduced silage intake (770 vs. 791g DM d^?1; -3%) and reduced liveweight gains. In Experiment 1 intakes of the D silages were 650–667g DM d^?1 and just maintained lamb live weights. Intakes of the P silages were 39–49% higher than the D silages (927–968 g DM d^?1) and increased liveweight gains. In Experiment 2 intakes of the D silages were 534–589 g DM d^?1 and resulted in a loss in lamb live weight. Precision-chopping increased silage intakes by 31–48% (770–791 DM d^?1)in Experiment 2 and improved lamb liveweight gains. Lamb performance was higher on the UP silage than on the WP silage. The rumen retention lime (RRT), estimated from the rumen contents of the lambs at slaughter and their silage intake before slaughter, was much shorter for the lambs fed on the P silages (12.6–20.6 h) than those fed on the D silages (21.4–29.3 h) in each experiment. Silage intake and liveweight gain were positively related to silage in vivo DM digestibility (DMD), whereas RRT was negatively related to DMD. However, there were distinct differences between the P and D silages in the elevation and, to a lesser extent, in the slope of the regression lines, indicating that intake of D silage was limited by factors other than the digestibility of the silage The results of this study show that the chop length of grass silage had a far greater effect on intake and on lamb performance than silage digestibility, whereas wilting had little or no effect.     

Mycotoxins in farm silages – a 2‐year Irish national survey

Toxicogenic fungal moulds have been previously identified in Irish farm silages and are known to be capable of producing mycotoxins. Mycotoxins are detrimental to animal health and performance and can be transferred through feed to animal produce. The objectives of this study were to identify and quantify the challenge posed to livestock from mycotoxins in Irish silages and determine whether conventional chemical characteristics could be used as indicators of mycotoxin occurrence. Over the 2‐year period, 300 silages were sampled on 150 farms and these consisted of round‐baled grass silages (n = 115) and pit silages of either grass (n = 175) or maize (n = 10). There was no significant difference in mycotoxin concentrations across silage types in either year, except for baled silage containing higher concentrations of enniatin B compared with pit silage in Year 1. Conventional chemical characteristics of silages were generally not reliable predictors for mycotoxin incidences; however, dry‐matter digestibility, crude protein, fermentation products and ash did predict the incidence of enniatins and beauvericin. The incidence and concentration of the twenty measured mycotoxins were generally low and individual mycotoxin concentrations recorded were considerably lower than current EU directive or guidance thresholds. Non‐regulated mycotoxins measured were similar to or lower than concentrations reported in the literature. Based on current knowledge and the concentrations of individual mycotoxins detected in this study, the challenge to Irish livestock and livestock products from animal consuming silage is generally low. However, the additive or synergistic effects of multiple mycotoxins in silage are unknown.     

The influence of grass and maize silage quality on apparent diet digestibility, metabolizable energy concentration and intake of finishing beef cattle

The effects of offering a range of grass silages and mixtures of grass and maize silages on the intake of beef cattle were studied. Four grass silages (GS1, GS2, GS3 and GS4) were used. Grass silage 1 was ensiled from a second regrowth in mid‐late September and treated with an inoculant additive. Grass silages 2, 3 and 4 were ensiled, without additive, from a primary regrowth harvested in early July, late May and mid‐June respectively. Wilting periods were 8, 30, 36 and 36 h for GS1, GS2, GS3 and GS4 respectively. Grass silages 1, 2 and 3 were precision chopped and ensiled in bunker silos, while GS4 was ensiled in round bales. The DM content (g kg^?1) and starch concentration (g kg^?1 DM) of the three maize silages (MS1, MS2 and MS3) used were 256 and 128, 256 and 184, and 402 and 328 for MS1, MS2 and MS3 respectively. Seventy‐two Charolais and Limousin cross‐bred steers were used in a changeover design with two 4‐week periods. The study consisted of sixteen treatments incorporating the four grass silages fed alone and with the three maize silages arranged as a 4 × 4 factorial design. The grass silage and maize silage mixtures were offered in a ratio of 0·60:0·40 (DM basis) once daily using individual Calan gates. All silages were offered ad libitum with 3 kg per head per day of a concentrate supplement. Dry matter and metabolizable energy (ME) intakes were highest with diets based on grass silage GS4 compared with diets containing the other grass silages. Metabolizable energy intakes of diets containing no maize silage, and those based on MS1 and MS2, were similar (P > 0·05) but lower than that of diets containing MS3. Only limited increases were found in DM and ME intakes with the inclusion of maize silage in grass silage‐based diets while offering high‐quality grass silage (assessed in terms of DM content, and fibre and N concentrations) promoted high voluntary intakes.     

Effect of two additives on the fermentation,in vitro digestibility and aerobic security of Sorghum–sudangrass hybrid silages

Two additives (Silo Guard (SG) and propionic acid (PA)) were tested for their effects on the quality and aerobic security of sorghum–sudangrass hybrid silages (JC‐1 and WC‐2). Two sorghum–sudangrass hybrid varieties were harvested for ensiling without additives (CK) or after the following treatments: SG at 0·5% of fresh forage or PA at 0·5% of fresh forage, with three replicates per treatment. The addition of SG and PA both affected the fermentation quality and chemical composition of the silages by lowering pH and NH₃‐N/TN and increasing lactic acid, the LA/TA ratio, WSC and CP concentrations compared with the untreated silages. In vitro DM digestibility (IVDMD), in vitro NDF digestibility (IVNDFD) and in vitro CP digestibility (IVCPD) were increased by SG in the JC‐1 silages and WC‐2 silages. Both additives improved the aerobic stability of sorghum–sudangrass hybrid silages. Furthermore, the additives reduced the mould counts and the aflatoxin and zearalenone levels compared with the untreated silages following aerobic exposure. Therefore, ensiling two sorghum–sudangrass hybrid varieties resulted in high‐quality silages. The addition of SG and PA improved silage quality, in vitro digestibility and aerobic security.     

Re‐ensiling and inoculant application with Lactobacillus plantarum and Propionibacterium acidipropionici on sorghum silages

Re‐ensiling of previously ensiled forage has been a common practice in Brazil, and the use of inoculants may provide a means of reducing dry‐matter (DM) loss. This study aimed to determine the effect of re‐ensiling and the use of microbial inoculants on the quality of sorghum silage. Treatments were presence/absence of an inoculant (Lactobacillus plantarum and Propionibacterium acidipropionici) in the silage, and the re‐ensiling, or not, of the material after 24 h of exposure to air, and these were tested in a factorial 2 × 2 design. Losses due to gas, effluent and total DM were assessed, as were the fermentation characteristics, chemical composition, aerobic stability, and aerobic counts of microorganisms. Effluent loss was higher in re‐ensiled silage, and these silages had lower lactic acid content and higher levels of acetic and propionic acids. The in vitro DM digestibility was lower in the re‐ensiled sorghum silages. The re‐ensiled silage had higher aerobic stability. The inoculant only increased the acetic acid content of the silage. The re‐ensiling of sorghum silage increased effluent loss by 71·2%, and reduced DM digestibility by 5·35%. The use of inoculant did not influence the quality of sorghum silage.     

The effect of physical form of a silage on its voluntary consumption and digestibility by sheep

Six castrated male sheep were used in a two-period crossover experiment to investigate the effect of mincing on the voluntary intake and digestibility of a silage. The silage was a high-quality material, containing 68 % digestihle organic matter in the dry matter, prepared from S24 perennial ryegrass cut with a precision chop forage harvester and ensiled with the addition of 2.3 1 t^?1 formic acid as preser vative. The median size of particles in the unprocessed silage was 10–20 mm and in the minced silage 2–3 mm. The intakes of dry matter, organic matter and nitrogen for the minced silage were greater than for the unminced material, and for dry matter and organic matter intakes the differences were signi ficant (P<0.01). Mincing was associated, however, with a depression in the digestibility of all three constituents which offset the increase in intake. The intakes of digestible organic matter were 817 g d^-1 for the minced silage and 729 g d^?1 for the unminced material (P>0.05). Corresponding figures for digestible nitrogen intakes were 208 gd^?1and23.0 gd^?1 (P>005). It is concluded that with high-quality silage diets there is a physical component in the mechanism for the control of voluntary food intake. It is suggested that for sheep, depressions in the digestibility of dietary constituents are unlikely to occur until silages are chopped to a median particle size of 5–10 mm.     

Effect of forage species and ensiling conditions on silage composition and quality and the feed choice behaviour of goats

The hypothesis was that forage species and ensiling conditions have an impact on the formation of biogenic amines and the feed choice of goats in short‐term preference trials. At ensiling, lucerne (Medicago sativa L., first cut), red clover (Trifolium pratense L., first cut) and Italian ryegrass (Lolium multiflorum Lam ., second cut) were treated differently to obtain a range of fermentation qualities. Six treatments of each forage species were prepared and included different dry‐matter concentrations, chemical and biological silage additives, and additions of soil. Silages were sampled for chemical analyses (proximate constituents, fermentation products and other volatile compounds, crude protein fractions and biogenic amines) and stored anaerobically in vacuum‐sealed plastic bags for use in preference trials (one trial for each forage species) with Saanen‐type wethers (n = 8 or 6). Each possible two‐way combination of the six silage treatments and a standard hay (n = 21 combinations) was offered for ad libitum intake for 3 hr. Data were analysed using multidimensional scaling, analysis of variance and correlation analysis between silage characteristics and dry‐matter intake (DMI). For each forage species, fermentation characteristics and crude protein fractions revealed only small differences among treatments. Although the degree of proteolysis, as measured by non‐protein nitrogen, of all silages was high, biogenic amine and butyric acid concentrations were low. The different treatments apparently had no direct influence on the formation of biogenic amines and feed choice. The preference behaviour within one forage species was strongly divergent, but DMI rankings of the three species were very similar.     

Effects of the proportions of high or medium digestibility grass silage and concentrates in the diet of beef cattle on liveweight gain, carcass composition and fatty acid composition of muscle

Abstract An experiment was carried out over 2 years to evaluate the effects of increasing the proportion of cereal‐based concentrates in diets containing high‐digestibility and conventional medium‐digestibility grass silages on the dry‐matter (DM) intake, liveweight gain and carcass composition of beef cattle, and to examine the effects of grazed grass and the ratio of grass silage:concentrates in the diet on the fatty acid composition of selected muscle tissues. Late‐maturing steers (n = 231) were offered diets based on high‐digestibility (HD) (0·743 digestible organic matter (DOM) in DM) or medium‐digestibility (MD) (0·643 DOM in DM) grass silages supplemented with barley/soyabean meal‐based concentrates. The concentrates constituted 0·20, 0·40, 0·60 and 0·80 of total DM of the diets, which were offered ad libitum (AL). The two diets, which contained 0·80 concentrates, were also offered at 0·80 of AL intake. A further group of fourteen animals were given the medium‐digestibility silage only for 5 months and then grazed perennial ryegrass pastures for a further 5 months (silage/pasture treatment). For the diets containing HD silage and 0·20, 0·40, 0·60 and 0·80 concentrate, and 0·80 concentrate at 0·8 of AL intake, the DM intakes were 9·4, 10·2, 10·4, 10·2 and 8·1 (s.e. 0·16) kg d^?1, respectively, and daily carcass gains were 0·67, 0·78, 0·77, 0·79 and 0·62 (s.e. 0·029) kg d^?1, respectively; for those containing MD silage and 0·20, 0·40, 0·60 and 0·80 concentrate, and 0·80 concentrate at 0·8 of AL, the DM intakes were 8·2, 9·3, 10·1, 10·1 and 8·0 (s.e. 0·16) kg d^?1, respectively, and daily carcass gains were 0·38, 0·48, 0·64, 0·77 and 0·56 (s.e. 0·029) kg d^?1 respectively. Increasing the proportion of concentrates in silage‐based diets decreased the concentration of omega‐3 (ω‐3) polyunsaturated fatty acids (PUFA) (P < 0·001) and increased the concentration of ω‐6 PUFA (P < 0·001) in muscle. Cattle on the silage/pasture treatment had the highest concentration of ω‐3 PUFA in muscle (51 g kg^?1 lipid), this value being over three times that for animals given diets containing MD silage and 0·80 concentrate in the diet. These results demonstrate the potential of HD silage made from perennial ryegrass relative to high concentrate diets. The consumption of pasture‐finished beef could make a significant contribution towards increasing the intake of ω‐3 PUFA in the human diet.     

Impact of ferulic acid esterase‐producing lactobacilli and fibrolytic enzymes on ensiling and digestion kinetics of mixed small‐grain silage

This study evaluated the effects of a ferulic acid esterase (FAE) and a non‐FAE‐producing inoculant applied alone or in combination with exogenous fibrolytic enzymes (EFE) on the fermentation and nutritive value of mixed grain (barley, oats and spring triticale) silage. The mixed crop was ensiled in laboratory mini‐silos either untreated (CON), or treated with a FAE inoculant (FAE), a non‐FAE inoculant (NFAE) or NFAE + EFE. Inoculated silages were lower (P < 0·01) in water‐soluble carbohydrate, whereas NFAE and NFAE + EFE silages had higher (P < 0·001) DM loss than other silages. FAE and NFAE silage had higher neutral detergent fibre (NDF), but were lower in NFAE + EFE than other silages (P < 0·001). Copy numbers of 16S rRNA associated with Lactobacillus buchneri were higher (P < 0·001) in NFAE and NFAE + EFE silages than in others, resulting in higher (P < 0·001) acetic acid in these silages. NFAE + EFE silage had lower (P < 0·001) in vitro gas production and NDF digestibility (NDFD) than other silages. FAE silage had higher (P < 0·01) in situNDFD than CON and NFAE + EFE silages. Inoculation of mixed small‐grain silage with NFAE‐producing inoculants combining EFE reduced NDFD.     

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.     

Intake, liveweight gain and feed preference by steers fed combinations of lucerne and Westerwolds ryegrass silages

Nutritive value and voluntary intake of legumes are generally considered to be higher than those of grasses when ensiled at similar digestibility, although high levels of soluble protein can result in low N utilization by animals and high losses to the environment. The objectives of this experiment were to describe the optimum combination of Westerwolds ryegrass ( Lolium multiflorum Lam. cv. Aubade) and lucerne ( Medicago sativa L. cv. AC Caribou) silages to maximize liveweight gain of steers fed silage, determine chemical components that are important and ascertain whether steers selected the optimum mixture when given a choice. Both silages contained similar concentrations of dry matter (DM), acid-detergent fibre (ADF) and organic acids, but lucerne silage had higher concentrations of N, soluble-N and ammonia-N. Westerwolds ryegrass silage contained more neutral-detergent fibre (NDF). In a 12-week experiment, voluntary intake by Hereford steers was not influenced when the proportion of the two silages was changed from 1 to 0 in 0·25 increments. However, liveweight gain and feed efficiency increased linearly ( P  < 0·001) as the proportion of ryegrass silage fed was increased. When preconditioned to either of the two silages, steers showed a significant preference for ryegrass over lucerne ( P  < 0·05). When conditioned to a mixture of both silages, no preference was elicited. It is suggested that extensive solubilization and deamination of protein in the lucerne silage may have caused the preference for Westerwolds ryegrass silage and the higher liveweight gains on diets containing higher proportions of Westerwolds ryegrass silage.     

Effects of feeding different ensiled forages on the productivity and nutrient-use efficiency of finishing lambs

The effects of offering ensiled red clover (Trifolium pratense), lucerne (Medicago sativa), pea (Pisum sativum), kale (Brassica oleracea) and hybrid ryegrass (Lolium hybridicum) on the productivity and nutrient‐use efficiency of lambs were investigated. Forages were cut, wilted for 24 h and ensiled as round bales. A hundred Suffolk‐cross lambs, aged 8 months, were offered grass silage during a 5‐week standardization period and then group‐housed for 14 d and offered ad libitum access to a treatment silage. For the measurement period, lambs were split into four replicate groups of five lambs per treatment. Dry matter intake and live weight were recorded every 7 d over 56 d. The chemical composition of the silages differed for all the variables measured. Lambs offered pea silage had a very low liveweight gain and this treatment was discontinued after 21 d. Lambs offered the other forages had a higher liveweight gain than lambs offered ryegrass silage (P < 0·001). Food conversion and nitrogen‐use efficiency were higher in lambs offered the red clover, lucerne and kale silages compared with those offered ensiled ryegrass (P < 0·001). These findings demonstrate the potential for using ensiled alternative forages rather than ryegrass to increase the productivity and nutrient use efficiency of livestock systems.     

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.     

Grass silage as a basic feed for store lambs. 3. Effect of barley supplementation of silages varying in chop length on silage intake and lamb performance

An experiment was carried out to study the effect of silage chop length and barley supplementation on silage intake and the performance of store lambs. The silages were cut from a perennial ryegrass regrowth at a relatively mature stage of growth in early July. Different types of harvester were used to produce a long silage (L), single-chopped (S), double-chopped (D), medium precision-chopped (MP) or a short precision-chopped (SP) silage. The chop length of the silages averaged 37.4, 12.4, 8.4, 7.0 and 2.9 cm respectively. All silages were treated with formic acid at 2.51 t^?1grass. They were well preserved and of a good quality with a dry-matter (DM) digestibility of 720–760 g kg^?1 DM. The silages were fed ad libitum to Suffolk crossbred store lambs over a period of 10 weeks. Each silage was fed either alone or was supplemented with whole barley at 400 g lamb^?1 d^?1. When offered silage alone, intakes were 738, 679, 773, 980 and 910 (± 30) g DM d^?1 for silages L, S, D, MP and SP respectively. Similar relative differences in intakes between the silages were evident when supplemented with barley. Liveweight gain on silage alone was higher on the precision-chopped silages (85–93 g d^?1) than the long or flail-chopped silages (28–49 g d^?1). Liveweight gain on the precision-chopped silages was also better when supplemented with barley (150 vs. 90–112 (± 90) g d^?1). Silage intake and lamb performance were similar for the MP and SP silages, despite the difference in chop length. Barley supplementation reduced silage intake to a similar extent for all silages (-9%) and increased total DM intake (+ 30%) and metabolizable energy intake (+ 37%). The substitution rates of silage for barley were similar for all silages and averaged 0.24 g silage DM g^?l barley DM. The response in weight gain per 100g of barley fed was similar for all silages and averaged 20.0 g liveweight gain and 13.4 g carcass gain. Feed conversion efficiency of the total diet was similar for the Mail-chopped and precision-chopped silages but was less for the long silage. The results of this study show that the benefit in weight gain due to the higher intake of precision-chopped silage was maintained when the silage was supplemented with a moderate level of barley. Such silage required supplementation with barley (400 g d^?l) to achieve a rate of liveweight gain of 150g d^?1.     

Inclusion of alfalfa improves nutritive value and in vitro digestibility of various straw–grass mixed silages in Tibet

To enlarge the feed resources and enhance the utilization efficiency of straws as ruminant feed in Tibet, four kinds of local crop straws with tall fescue (Festuca arundinacea Schreb.) based on the ratio of 40/60 (fresh weight) were ensiled with four levels (0, 10%, 20% and 30% of fresh weight) of alfalfa (Medicago sativa L.), respectively. The laboratory silos (1L) were opened after 45 days of ensiling, and the fermentation characteristics, nutritive value and in vitro digestibility of the mixed silages were analysed. The silages including alfalfa had significantly (p < 0.05) or numerically (p > 0.05) higher lactic acid and crude protein contents, lactic acid bacteria counts, in vitro digestibility of dry matter, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and lower NDF and ADF contents than controls. The results suggest that inclusion of alfalfa to mixtures of straws and tall fescue had favourable effects on fermentation quality and obviously improved the nutritive value and in vitro digestibility of mixed silages. This effect was most evident when the inclusion proportion of alfalfa was 30% in oat straw mixed silage.