Production of dairy cows fed whole-crop cereals or ryegrass silages supplemented with a fixed amount of concentrate

Abstract

Feed intake and milk production responses to whole-crop cereal silages and ryegrass silage (RGS) supplemented with a fixed amount of concentrate were measured in three 4×4 Latin square-designed experiment with three 17-day periods using 12 Holstein cows. Diets consisted of a fixed amount of concentrate (10 kg) and one of the following silages offered ad libitum: RGS, Mondego wheat silage (MWS), Alva wheat silage (AWS), and triticale silage (TS). Silage dry matter intake and milk yield were significantly higher for RGS. Milk composition was not affected by silage treatment. The whole-crop cereal silages tended to show higher milk concentrations of anteiso C15:0, iso C15:0, C16:1 and C18:1 and lower concentrations of C18:2 and C18:3. This study suggests better response of dairy cows to a single cut RGS than to whole-crop cereal silages harvested in an early stage of maturity.     

Partial substitution of whole-crop corn with bamboo shoot shell improves aerobic stability of total mixed ration silage without affecting in vitro digestibility

To evaluate the feasibility of bamboo shoot shell (BSS) application in total mixed ration silage (TMR) production, the effects of BSS substitution for whole-crop corn on the fermentation characteristics, nutritive value, aerobic stability and in vitro parameters of TMR silage were studied. Four TMR formulations were designed based on dry matter: (1) 0% bamboo shoot shell + 23% whole-crop corn (BSS₀); (2) 4% bamboo shoot shell + 19% whole-crop corn (BSS₄); (3) 8% bamboo shoot shell + 15% whole-crop corn (BSS₈); and (4) 12% bamboo shoot shell + 11% whole-crop corn (BSS₁₂). After 90 days of ensiling, the silos were opened and sampled for fermentation characteristics, nutritive value and in vitro analyses, and subsequent 14-day aerobic stability test. All TMR silages were well preserved except BSS₁₂, characterized by high lactic acid content and V-score, low pH and NH₃-N and butyric acid content. With increasing proportion of BSS, crude protein increased (p <.05), and water soluble carbohydrate decreased (p < .05). Under aerobic exposure, BSS-substituted (BSS₄, BSS₈ and BSS₁₂) silages were more stable than BSS₀ silage, as characterized by relatively low silage temperature and high water soluble carbohydrate content. No obvious (p> .05) difference of BSS substitution was observed on in vitro ruminal gas production, digestibility, metabolizable energy and net energy for lactation. The substitution of whole-crop corn with 4% BSS and 8% BSS had no undesired effect on the fermentation characteristics and in vitro digestibility, and efficiently improving the aerobic stability of TMR silages. The BSS₈ substitution level is recommended to maximize the BSS utilization.     

A survey of fermentation products and bacterial communities in corn silage produced in a bunker silo in China

To evaluate the current practice of corn silage management in China, samples of bunker‐made silage were collected from 14 farms within a 500‐km radius of Beijing for the analysis of fermentation products and bacterial communities. Mean values for dry matter (DM) content were as low as 250 g/kg in both corn stover (St) and whole crop corn (Wc) silages, and pH values averaged 4.48 and 3.73, respectively. Only three of the 14 silages exhibited a lactic‐to‐acetic acid ratio > 1.0, indicating that the presence of acetic acid was predominant in fermentation. Although 1,2‐propanediol content was marginal in most cases (< 5.0 g/kg dry matter (DM)), two Wc silages had 1,2‐propanediol levels > 25 g/kg DM. In contrast, 3 St silages had large amounts (> 10 g/kg DM) of butyric acid, and two of the three butyrate silages also had high concentrations of 1‐propanol. Denaturing gradient gel electrophoresis analysis demonstrated that the bacterial community appeared similar in 10 out of the 14 silage samples. Bands indicating Lactobacillus buchneri, L. acetotolerans and Acetobacter pasteurianus were found in both the St and Wc silages, accounting for the high acetic acid content found across silage samples.     

Effects of urea addition on the fermentation of sorghum (Sorghum bicolor) silage

This study was conducted to evaluate the effects of urea addition on fermentation characteristics, losses and chemical composition of silage of sorghum (Sorghum bicolor) ‘BRS Ponta Negra’. The sorghum plant was chopped and treated with different levels of urea (0.1756, 0.3512, 0.7024 and 1.4048 g per 10 kg fresh forage for the respective proportions of 0.5%, 1.0%, 2.0% and 4.0% of forage (dry matter [DM] basis), and packed into quintuplicate experimen- tal silos to determine its effects on fermentation, losses and chemical composition of sorghum silages. Addition of urea increased lactic acid bacteria up to the level of 60 g kg^?1 (DM basis). Compared with control silage, the addition of urea (p < 0.05) reduced DM losses. Urea-treated silages linearly increased (p < 0.05) the ammoniacal nitrogen and crude protein contents, and linearly reduced (p < 0.05) the ethanol content. The pH in urea-treated silages indicated better preservation of substrates obtained from fermentation. The intermediate level of 2.0% urea additive can be used to improve fermentation, reducing losses in sorghum silage without compromising lactic acid production. However, the addition of 0.5% and 1.0% urea to sorghum silage is sufficient to improve aerobic stability.     

青贮菌剂在苜蓿裹包青贮中的应用效果

在苜蓿裹包青贮中添加3种不同青贮菌剂JD6、MMD3、X3Q2,分析青贮苜蓿的营养品质,微生物数量以及瘤胃降解率的变化,以研究3种青贮菌剂在裹包青贮条件下对苜蓿青贮的影响。结果表明,青贮5个月后,添加青贮菌剂可以显著降低pH值(P<0.05)、NH3/TN值(P<0.05),减少丁酸含量(P<0.01),有利于保存青贮物的营养成分,提高青贮品质。添加青贮菌剂对青贮物的NDF、ADF含量没有影响,对青贮产物干物质和NDF的瘤胃降解率没有影响。添加青贮菌剂可以提高青贮产物中乙酸含量(P<0.05),减少酵母菌和霉菌数量(P<0.05)。3种青贮菌剂在苜蓿裹包青贮试验中,有利于抑制有害微生物,保存苜蓿营养成分,提高苜蓿青贮品质和有氧稳定性。     

Influence of replacing corn silage with barley silage in the diets of buffalo cows on milk yield and quality

A 150-day trial was carried out on 40 Italian Mediterranean buffalo cows that, immediately after calving, were equally divided into two homogeneous groups (M and O) based on the number of calving events and previous milk yield. The animals were fed (16 kg dry matter (DM)/head) two isoenergy/isoprotein diets (NEl: 6.39 MJ/kg DM; 15.4 CP% DM), composed of corn (diet M) or barley silage (diet O) concentrate, alfalfa hay, and a vitamin-mineral supplement. The fermentation characteristics of both silage diets were evaluated by an in vitro gas production technique, and their nutritional values were calculated as follows: NEl (MJ/kg DM) = 0.54 + 0.0959 GP + 0.0038 CP + 0.0001733 CP², where GP is the gas production after 24 h of incubation (ml/200 mg DM) and CP is the protein content of silage (g/kg DM). The nutritional values of the silages were slightly different (4.16 vs. 4.14 MJ/kg DM for M and O, respectively) likely due to the high content of hemicellulose in the O diet (22.0 vs. 16.9%). Average milk yield did not differ between the groups; instead, milk fat (8.39 vs. 9.06%; P < 0.01) and protein (4.41 vs. 4.60%; P < 0.01) levels were significantly higher in the O group. The results elicit great interest in southern Italy where corn cultivation is adversely affected by the high cost of irrigation.

     

Feeding value of ensiling fresh cattle manure with molasses or bakery by-products in lambs

Ensiling fresh dairy cattle manure (CM), corn stover, molasses (MO) or bakery by-products (BBP), as a viable method to produce good quality silage was evaluated. Silages composition was as follows: 1) molasses silage: CM, corn stover and molasses; and 2) BBP silages: CM, corn stover, and BBP. A low (250 g/kg dry matter) and a high (500 g/kg dry matter) level of CM with MO or BBP silages were incorporated in diets, and compared with a control diet (without CM silage) in lambs. There was a linear increase (P < 0.01) of dry matter (DM) intake and a quadratic increase of fiber digestion. Linear decrease (P < 0.05) in acetate to propionate ratio was observed with increased concentrations of MO or BBP in silages. Increasing MO silage caused a linear reduction of N intake and retained N, as well as a linear increase of fecal N. There were quadratic effects of BBP silage level on N intake, urine and retained, being the lowest values observed with the low level of BBP silage. Addition of BBP silages (250 or 500 g/kg DM) bring higher DM intake and total tract digestion of fiber, as compared to those diets without CM silage.     

A third-generation esterase inoculant alters fermentation pattern and improves aerobic stability of barley silage and the efficiency of body weight gain of growing feedlot cattle

This study investigated the effects of a mixed bacterial inoculant possessing ferulic acid esterase (FAE) activity on silage fermentation characteristics, aerobic stability, and growth performance of growing feedlot steers. Whole-crop barley (Hordeum vulgare L.) forage (35% DM) was chopped and ensiled without a silage inoculant (UN) or with a mixed bacterial culture containing 1.0 × 10(11) cfu/g of Lactobacillus buchneri LN4017 that produces FAE, 2.0 × 10(10) cfu/g of Lactobacillus plantarum LP7109, and 1.0 × 10(10) cfu/g of Lactobacillus casei LC3200 at a combined rate of 1.3 × 10(5) cfu/g of fresh forage (IN) in mini and Ag-Bag (Ag-Bag Int. Ltd., Warrenton, OR) silos. Silages from the mini silos were assessed for the effect of inoculation on fermentation characteristics and aerobic stability, whereas silages from Ag-Bags were used to formulate 2 barley silage-based total mixed rations (UN and IN) that were fed to growing feedlot steers for 112 d. The IN silage exhibited a homolactic fermentation during the first 7 d of ensiling as reflected by an increased (P ≤ 0.02) lactic acid concentration and an accelerated rate (P < 0.01) of pH decline. Thereafter, fermentation of IN silage became more heterolactic, resulting in greater concentrations of acetic acid (P < 0.01) and pH (P < 0.01) but less (P < 0.01) lactic acid than UN silage. Inoculation did not affect DM losses (P = 0.52) from mini silos. The IN silage remained stable during 21 d, but temperature and yeasts counts in the UN silage increased after 5 d of aerobic exposure. Growing steers fed the IN silage diet had superior (P = 0.03) feed conversion efficiency compared with those fed UN silage. Inoculation of whole-crop barley silage with a mixed culture of homolactic lactic acid-producing bacteria and FAE-producing L. buchneri at ensiling changed fermentation from a homolactic to a heterolactic form during ensiling and improved aerobic stability of the silage and efficiency of BW gain of growing feedlot steers.     

丙酸和丙酸菌添加对高油玉米秸秆青贮发酵品质以及瘤胃发酵参数影响的研究

试验以完熟期的高油玉米秸秆为青贮原料,分别为对照组(无添加剂)、丙酸处理组(0.5%/kg鲜样)、丙酸菌处理组(105cfu/g鲜样)。在青贮的第1、3、6、9周开瓶取样检测丙酸和丙酸菌对青贮发酵质量的影响。结果表明:3种处理均得到优质青贮(低pH、高乳酸含量、未检测到丁酸)。活体外试验表明,丙酸处理青贮的72h累积产气量和总挥发性脂肪酸(VFA)产量均显著高于丙酸菌处理和自然发酵青贮(对照组)。但是3种处理青贮的活体外消化率没有显著(P>0.05)差异。     

瘤胃纤维素降解菌系对灭菌水稻秸秆结构性碳水化合物降解的影响

为了提高水稻秸秆的青贮发酵品质,本研究旨在从黑白花奶牛瘤胃中筛选出具有降解纤维素能力的兼性厌氧复合菌系,探讨其对水稻秸秆青贮过程中结构性碳水化合物降解及发酵品质的影响。试验采集了黑白花奶牛瘤胃内容物,经富集培养、刚果红染色初筛,耐酸诱导,滤纸降解复筛,酶活力测定,获得高效兼性厌氧纤维素降解复合菌系M6。试验设4个处理组：1）水稻秸秆直接自然青贮（CK）组;2）灭菌后水稻秸秆青贮（IRR）组;3）灭菌水稻秸秆接种复合乳酸菌（CLAB）青贮组;4）灭菌水稻秸秆接种复合菌系（M6）青贮组,分别于青贮3、6、15、45、60和90 d后开窖取样分析。结果表明,青贮3 d后,M6处理组pH始终低于其他各组,青贮第60天达到最低值（4.62）。青贮45 d后,M6处理组乳酸含量始终显著高于其他各组（P<0.05）,且在青贮90 d达到最高值（23.90 g·kg^-1 DM）。青贮15 d后,中性洗涤纤维、酸性洗涤纤维和纤维素含量在M6组均显著低于其他各组（P<0.05）,且在第90天达到最低值。青贮60 d后,IRR和M6组保持较高水平的水溶性碳水化合物含量,其次为CLAB组。综上所述,复合菌系M6在水稻秸秆青贮过程中具有降解粗纤维和促进乳酸发酵的作用,添加纤维素降解复合菌系可有效改善水稻秸秆青贮发酵品质,为青贮添加剂的研发与应用提供了理论依据。     

玉米秸秆及青贮饲料的细胞壁成分体外消化性能比较

利用体外消化试验法,对吉单4011和四单29两品种玉米的秸秆和青贮饲料进行了干物质和细胞壁成分的消化率和消化速度常数的测定,吉单4011的干物质(DM)和细胞壁成分(OCW)的有效消化率分别是57.4%和48.9%,吉单29分别是58.8%和53.9%。两品种玉米青贮饲料OCW的消化速度常数显著高于秸秆,吉单4011的秸秆和青贮饲料分别为4.85%和4.52%,吉单29分别为5.81%和7.11%。结果表明,通过青贮,可以提高玉米秸秆细胞壁的消化率和消化速度常数,秸秆中OCW含量高的玉米品种更适合青贮。     

Identification of bacteria in total mixed ration silage produced with and without crop silage as an ingredient

As a forage source for total mixed ration (TMR) silage production, locally produced crop silage is now used in addition to imported hay. This type of TMR ensiling is regarded as a two‐step fermentation process; hence, a survey was carried out to determine whether the bacteria in crop silage affect the subsequent TMR ensiling. Fermentation product contents and bacterial community were determined for TMR silage and its ingredient silages collected in August, October and November. August product contained corn, sorghum and Italian ryegrass silages, October product had wheat silage exclusively and November product did not include any crop silages. Acetic acid, lactic acid, 2,3‐butanediol and ethanol were predominant fermentation products in corn, sorghum, Italian ryegrass and wheat silages, respectively. Robust lactic acid fermentation was seen in TMR silage, even if acetate‐type and alcohol‐type silages were mixed as ingredients. The finding that bacterial community of the TMR silage appeared unrelated to those of ingredient silage supported this. Silages of various fermentation types can therefore be formulated without interfering with lactate‐type fermentation in TMR silage.     

晾晒、添加物及不同温度对象草青贮发酵品质和微生物的影响

华南地区气候潮湿多雨,象草收获时水分含量高,单独青贮发酵品质较差。通过晾晒（水分含量由83.19%降至75.11%）、添加10%玉米粉或2%蔗糖,探究象草在不同温度（20、30和40 ℃）下青贮的发酵特性和微生物组成。研究结果表明：温度对象草各处理的青贮饲料的发酵品质有显著影响。晾晒后原材料的水溶性碳水化合物含量显著降低,青贮后发酵品质变差,尤其在30 ℃,pH达到5.85,乳酸含量只有1.56% DM,乙酸含量为2.10% DM,NH₃-N含量高达25.09% TN。对照和添加物处理的青贮饲料均随青贮温度升高,乙酸含量增加。晾晒后在20和30 ℃时青贮,产气量显著高于40 ℃或未晾晒处理。此外,象草青贮前的细菌多样性较丰富,青贮后主要是肠杆菌属和乳球菌属,尤其是20 ℃青贮的相对丰度较高,且晾晒处理在20和30 ℃青贮肠球菌属的相对丰度高于40 ℃。因此,在华南地区,象草原料中添加玉米粉或蔗糖可以降低环境温度对象草青贮发酵品质的不良影响,阴湿条件下晾晒未发挥积极效果。     

The effect of cutting time of grass silage in primary growth and regrowth and the interactions between silage quality and concentrate level on milk production of dairy cows

Two silages were prepared from the primary growth (PG) of timothy-meadow fescue sward at early (E) and late (L) stage of growth. The subsequent regrowth (RG) areas were further harvested at early (EE and LE) and late (EL and LL) stages of growth resulting in six silages in total. The silages were fed ad libitum to 24 lactating Finnish Ayrshire cows and supplemented with 8 or 12 kg concentrate per day in a cyclic change-over experiment with four 21-day periods and 6 × 2 factorial arrangement of treatments. The quality of silages varied markedly within and between the harvests although variation was greater within PG than RG. Postponing the harvest in PG decreased silage dry matter (DM) intake by 0.48 kg and energy corrected milk yield (ECM) by 0.61 per 10 g decrease in silage D-value (concentration of digestible organic matter in DM), while responses and the range between the diets were clearly smaller when RG silages were fed. On average, ECM yield was higher when PG rather than RG silages were fed. The mean response to increased concentrate DM intake was 0.62 kg ECM using diets based on PG. The response increased with increasing growth stage of grass being 0.34 and 1.01 kg ECM / kg additional concentrate DM for E and L, respectively. The difference was mainly mediated by the differences in substitution rates (reduction in silage DM intake per increase in concentrate DM intake, kg/kg), which were 0.71 and 0.22 for E and L, respectively. The ECM response to increased concentrate allowance was on average greater when RG rather than PG silages (0.92 vs. 0.62 kg/kg concentrate) were fed. Milk production of dairy cows reflected the intake of metabolizable energy and no differences in the utilization of it were found between diets based on silages harvested from PG and RG. However, intake of RG silages was slightly lower than that of comparable PG silage, but definite reasons for that could not be identified.     

Improvement of whole crop rice silage nutritive value and rumen degradability by molasses and urea supplementation

Whole crop rice was harvested 120 days after planting and chopped to 2–3-cm length for silage making. The whole crop rice silage (WCRS) was supplemented with different levels of molasses and urea to study nutritive value and in situ rumen degradability. The ensiling study was randomly assigned according to a 6?×?5 factorial arrangement, in which the first factor was molasses (M) supplementation at M0, M1, M2, M3, M4, and M5 %, and the second was urea (U) supplementation at U0, U0.5, U1.0, U1.5, and U2.0 % of the crop dry mater (DM), respectively. After 45 days of ensiling, temperature, pH, chemical composition, and fermentation end products of the silages were measured. Ten U and M treatment combinations of WCRS were subsequently selected to study rumen degradability by nylon bag technique. The results showed that temperature and pH of the silages linearly increased with U supplementation level, while total volatile fatty acid (TVFA), acetic acid (C2) and propionic acid (C3) decreased. In contrast, increasing level of M supplementation decreased WCRS temperature and pH, whereas TVFA, C2, and C3 concentrations increased dramatically. Both M and U supplementation increased concentration of butyric acid (C4). Dry matter, organic matter (OM), and acid detergent fiber (ADF) contents of the silages were not influenced by either M or U supplementation. Increasing U supplementation increased crude protein (CP) content, while M level did not show any effect. Furthermore, neutral detergent fiber (NDF) content in silage was decreased by both M and U supplementation. The results of the in situ study showed that M and U supplementation increased both ruminal DM and OM degradation. The water-soluble fraction (a) was the highest in WCRS U1.5M3 and lowest in U0M0. Increasing M and U supplementation levels increased the potentially degradable fraction (b) of both DM and OM. Total rumen degradable fraction (a?+?b) was highest in WCRS U1.5M3, whereas OM degradability was highest in U0M3. However, effective degradation of both DM and OM were the highest in WCRS U1.5M3 and the lowest in U0M0. We conclude that supplementation of U and M increases WCRS quality and rumen degradability. Supplementation of U at 1.5 and M at 3–4 % of the crop DM is recommended for lactating dairy cows and fattening beef cattle.     

鸡干扰素的研究进展

干扰素自发现以来,它的抗病毒、抗肿瘤和免疫调节机制逐渐清晰,而现在它的抗病毒机制中信号传导途经及分泌表达的调节正成为研究热点。作者就上述方面作一综述。     

Ensiling of total mixed ration containing persimmon peel: Evaluation of chemical composition and in vitro rumen fermentation profiles

The effects of inclusion of persimmon peel (PP) in total mixed ration (TMR) silage on its nutrient composition, tannin content, and in vitro ruminal fermentation were studied. Four types of TMR silages containing 0, 50, 100, and 150 g/kg of PP on a dry matter basis were prepared. The dietary contents of non‐fiber carbohydrate (NFC) decreased, while soluble protein fraction increased after ensiling of the TMR. In the TMR silages, the content of insoluble tannin increased (p < .05) with increasing PP level. The fraction of soluble protein decreased linearly (p < .01), while that of neutral detergent insoluble protein increased linearly (p < .01) with increasing the PP level in the TMR silages. The total gas and methane yields from the in vitro rumen fermentation of the TMR silages were lower (p < .01) than those of pre‐ensiled TMR and declined linearly (p < .01) with increasing PP level. These results indicate that adding PP to TMR silage may resist the breakdown of dietary protein during the ensiling process, although the ruminal fermentability of TMR possibly decreased after ensiling due to the loss of NFC.     

Nutritive value and fermentation quality of palisadegrass and stylo mixed silages

The nutritive value and fermentation quality of palisadegrass (Brachiaria brizantha cv. Xaraes) and stylo (Stylosanthes capitata × S. macrocephala cv. Campo Grande) mixed silages were evaluated. The experiment was analyzed in a factorial scheme (5 × 2) in a completely randomized design using increasing levels of stylo (0, 25, 50, 75 and 100% on a fresh matter basis) on palisadegrass silages, with and without microbial inoculants (MI). With the increased ratio of stylo in mixed silages, dry matter (DM), crude protein (CP), acid detergent fiber (ADF), and lignin content increased in silages. The presence of MI promoted lower DM content, and higher neutral detergent fiber corrected for ash and protein, ADF and lignin content. The acid detergent insoluble nitrogen content and the lactic acid bacteria populations were not affected by treatments. The in vitroDM digestibility was affected by the interaction of levels of the stylo and MI. The pH, NH₃‐N/total nitrogen and butyric acid concentrations decreased with increasing levels of stylo. Better nutritive value and quality of fermentation was found in the silage containing higher proportions of this stylo mixed with palisadegrass. The microbial inoculant evaluated did not alter the nutritive value or quality of the fermentation of the silages in this experiment.     

Effects of inoculants on the fermentation characteristics and in vitro digestibility of reed canary grass (Phalaris arundinacea L.) silage on the Qinghai‐Tibetan Plateau

To effectively use local available grass resources to cover the winter feed shortage on the Qinghai‐Tibetan Plateau, direct‐cut and wilted reed canary grass (RCG) silages were prepared by using a rolled‐bale system, and their ensiling characteristics and in vitro digestibility were studied. Silages were treated without (control) or with inoculants including LP (Lactobacillus plantarum), LPLB (L. plantarum, L. buchneri), and LPLBc (L. plantarum, L. buchneri, and cellulase), and were stored at ambient temperature (5.7–14.6°C) for 90 days. Compared with control, the inoculated silages increased (p < .05) lactic acid and acetic acid contents, and reduced (p < .05) final pH value and ammonia‐N ratio of total N. The highest WSC content (41.2 g/kg DM) occurred for LPLB‐inoculated silage, whereas LPLBc‐treated silage displayed the lowest contents of NDF (522.9 g/kg DM) and ADF (275.5 g/kg DM). In addition, LPLBc‐inoculated silage had the highest in vitro gas production (51.0 ml/g DM), in vitro DM digestibility (619.3 g/kg DM), and metabolic energy (9.6 kJ/kg DM). These results confirmed that treatments with inoculants at ensiling could improve silage fermentation and in vitro digestibility of RCG, and this could be a potential winter feed for animals on the Qinghai‐Tibetan Plateau.     

Fermentation kinetics of sainfoin hay with and without PEG

The in vitro gas production technique was applied to evaluate the biological activity of tannins in sainfoin (Onobrychis viciifolia Scop.) hay cut at four progressive phenological stages. The buffalo (Bubalus bubalis) rumen fluid was used as inoculum, polyethylene glycol (PEG) was added as specific binding agent and an alfalfa hay (AH) was used as control. All samples were analysed for chemical composition and condensed tannin (CTs). According to the phenological stage of sainfoin, crude protein gradually decreased [from 219 to 122 g/kg dry matter (DM)] and neutral detergent fibre (NDF) increased (from 391 to 514 g/kg DM). Condensed tannins showed the highest value at the first phenological stage [31.5 mg catechin equivalents (CE)/g DM], and their level significantly decreased at the subsequent growth stages. Gas production and fermentation rate were significantly affected by substrate type and PEG addition. The first stage of sainfoin showed the lowest value of gas and volatile fatty acids production and the slowest fermentation kinetics compared with the other samples, when incubated without PEG, because of the CTs effect. The incubation with PEG improved the fermentation process of the first stage of sainfoin, but no effect was registered on AH, where CTs were not detected. Among the sainfoin samples, the slowest kinetics with PEG was observed in the hay harvested at the fourth stage, probably due to its chemical composition. The use of PEG allowed to verify the effect of tannins on the in vitro fermentation characteristics of sainfoin hay.