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1.
Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling.  相似文献   

2.
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.  相似文献   

3.
The concept is presented of combined cultivation of legumes and sorghum–maize and their use as conserved ruminant feed in tropical regions, with special reference to Cuba. Good yields are obtained during the rainy season through intercropping (alternate rows of either sorghum or maize and soybean). When followed by ensiling, this provides high‐quality ruminant feed for the tropical dry season. Soybean compensates for the low crude protein content of sorghum, whereas sorghum allows good silage quality in combination with legumes. The paper reviews and updates recent studies assessing combined sorghum–soybean cultivation and ensiling as well as determination of their feed value. The high nutritive quality and forage potential when these crops are intercropped demonstrate that silage from these plants can be used successfully in ruminant diets in Cuba and other tropical areas. Perspectives for new studies in this field are suggested, particularly with legume species that are more adapted to specific tropical regions and/or with higher forage yield. In addition, it is suggested that there is a need to assess the supplementation impact on meat and milk production at the farm level, as well as its environmental impact, when ruminants are fed combined silages from whole plants of sorghum–legumes.  相似文献   

4.
High‐quality grass silages may represent a mitigation option by reducing enteric methane production and by increasing productivity, thus reducing greenhouse gas emissions per kg of product (emission intensity). Two previous studies found considerable effects of three different silage qualities cut at different maturity stages (very early [H1], early [H2] and normal [H3]) offered ad libitum with various levels of concentrate supplementation, on animal performances of growing/finishing bulls and dairy cows in early lactation, indicating that emission intensities may also vary. Based on results from these previous studies, the aim of this study was to estimate emission intensities for milk and beef carcasses for the included combinations of silage qualities and concentrate levels, by using the farm‐scale model HolosNor. The emissions intensities were lowest for the H1 silage, and highest for the H3 silage, independent of concentrate levels for both milk and beef. Thus, increasing concentrate levels did not compensate for lower grass silage quality. Improvements in silage quality from H3 silage to H2 is realistic and has the potential to reduce emission intensities with approximately 10% while keeping the milk yield per cow constant and reducing the use of concentrates considerably. For beef production, the potential is even larger, with a reduction in emission intensity of approximately 17%. We conclude that improving grass silage quality may be a mitigation option that will also reduce the dependence on concentrates.  相似文献   

5.
Highlights of progress in the production of silage over the past 50 years include the introduction of improved hybrids of maize (Zea mays L.), the forage harvester, the big baler, polyethylene covering for horizontal silos, stretch‐wrap film for bales and novel additives designed to improve the fermentation and aerobic stability of silage. The key biochemical pathways in the silage fermentation have been described together with the effects of microbial and chemical additives on fermentation and aerobic stability during the feed‐out phase. The significance of oxygen and water in silage fermentation has been quantified and efficacy of covering silos has been established, with recent progress in the development of oxygen barrier film. Future perspectives include improving food safety and animal health by increasing the hygienic quality of silage, reducing the environmental impact of silage by decreasing loss of nitrogen to soil and atmosphere, reducing methanogenesis in the rumen and increasing methane yield from silage as biofuel, and the use of silages as feedstocks for multiple end uses in biorefineries.  相似文献   

6.
To reduce losses and improve forage use efficiency in dairy farming systems, mass and nutrient flows during silage production have to be measured from the field to feed bunk. However, data on these losses at the farm scale are scarce. Thus, we examined dry‐matter (DM) losses and changes in nutrient concentrations (proximate constituents, nitrogen [N], phosphorus [P]) and energy values (net energy for lactation [NEL]) of silages on three experimental farms from ensiling to feed‐out. The investigated material included forages from permanent grassland and whole‐crop maize that were stored in 64 side‐walled bunker silos. To determine DM losses, the total‐in versus total‐out method was applied. Additionally, the changes in the nutrient concentrations were measured by comparing the concentrations before and after ensiling. Data analyses were carried out by using ANOVA, and the means across groups were compared via multiple contrast tests. On average, the farms had good silage production management. Average values showed a trend towards higher DM losses during the ensiling process with grass (9%) than maize (7%). The N and P concentrations of the silages remained mainly unchanged during the ensiling process, suggesting that the total losses of N and P were also low (<10%). Regarding the fibre fractions, ensiling resulted in a significant reduction in the concentration of amylase‐treated ash‐excluded neutral detergent fibre (aNDFom) for grass (11%) and maize (15%), while ash‐excluded acid detergent fibre (ADFom) was not affected by the ensiling process. These changes resulted in slightly improved energy values in the silages.  相似文献   

7.
Based on experimental data gathered in a research project on nitrogen fluxes in intensive dairy farming in Northern Germany, an analysis of fossil energy input and energy efficiency in forage production from permanent grassland and maize for silage was conducted. Field experiments comprised different defoliation systems and different rates of mineral N fertilizer and slurry application. Each change from grazing to cutting in grassland systems reduced the energy efficiency. Energy efficiency consistently decreased with increasing rates of mineral N application. In the production of maize for silage, maximum energy efficiency was obtained with an application of 50 kg N ha?1 from slurry only. Net energy yields of maize for silage were much higher than that of grassland when compared at the same level of fossil energy and nitrogen fertilizer input. Considering both nitrate‐leaching losses and a necessary minimum quantity of grass herbage in a well‐balanced ration, it is suggested that a high proportion of maize for silage in combination with N‐unfertilized grass/clover swards used in a mixed cutting/grazing system represents a good trade‐off between the leaching of nitrates and energy efficiency.  相似文献   

8.
Abstract In view of the evidence indicating several potential benefits of high intakes of conjugated linoleic acid (CLA) on human health, an experiment was conducted to examine the effects of the diet of beef cattle on the total CLA concentration in muscle and subcutaneous fat. High‐concentrate [steers consumed 515 g concentrates and 485 g grass silage kg?1 dry matter (DM) for 8 weeks followed by 887 g concentrates and 113 g grass silage kg?1 DM for 14 weeks until slaughter] and high‐forage (steers consumed 803 g grass silage and 197 g concentrates kg?1 for 8 weeks followed by grass silage only for 10 weeks and then grazed perennial ryegrass‐based pasture for 23 weeks until slaughter) treatments were imposed on 48 steers, which were crosses of continental beef breeds (initially 414 kg live weight) The concentrates were based on barley, extracted soyabean meal, molassed sugarbeet pulp and maize meal. The silages were of medium to low digestibility and contained 117–137 g crude protein kg?1 DM and 83–158 g ammonia‐N kg?1 total N. The pasture was of high quality and contained 168 g crude protein, 234 g acid‐detergent fibre and 222 g water‐soluble carbohydrate kg?1 DM. Samples of muscle were taken post slaughter from the m. semimembranosus, m. gluteobiceps, m. longissimus and m. deltoideous muscles, and subcutaneous fat was taken from over the m. longissimus. Concentrations of total CLA in the tissues were for the high‐concentrate and high‐forage treatments, respectively (mg 100 g?1 fresh tissue), m. gluteobiceps 18 and 47 (s.e. 3·5); m. semimembranosus 9 and 20 (s.e. 1·6); m. longissimus 15 and 35 (s.e. 3·2), m. deltoideous 20 and 59 (s.e. 4·3); subcutaneous fat 584 and 1975 (s.e. 138·7). It is concluded that muscle and subcutaneous fat tissue from grass‐fed cattle contained three times as much CLA as those from concentrate‐fed cattle, and that the consumption of beef from grass‐fed cattle should be effective in increasing the intake of CLA by humans.  相似文献   

9.
This review examines the response in intake of silage and animal performance after wilting of grass before ensiling. It uses data from eighty‐five published comparisons. Initial analysis identified those variables having the greatest influence on the increase in dry‐matter (DM) intake of grass silage owing to wilting. Total water loss, drying rate of the wilted material and ammonia‐N concentration of the unwilted material were the variables most closely and positively correlated to the proportional increase in DM intake as a result of wilting, with r2 values of 0·344, 0·393 and 0·240 respectively. There was little evidence of curvilinearity in any of the relationships. Stepwise regression analysis was used to identify the best multiple linear regressions for predicting the proportional increase in intake owing to wilting. Factors associated with the extent and rate of water loss in the field (total water loss and drying rate) and the quality of the unwilted material ensiled and its subsequent fermentation pattern (DM digestibility, crude protein, ammonia‐N content of unwilted silage) were the key variables in the relationship. Subsequent analysis related the increase in output of milk energy of dairy cows and liveweight gain of beef cattle to the same independent variables. This indicated that variables shown to describe the response in DM intake in the previous analysis were among those most closely related to the increases in animal performance owing to wilting of grass. To assess whether the increase in animal performance owing to wilting could be explained as a direct response to increased metabolizable energy (ME) intake of wilted compared with unwilted silages, linear relationships were derived between the increase in milk and beef production parameters and the increase in ME intake owing to wilting. From these, it was concluded that there was no clear evidence that wilting reduced the efficiency of utilization of ME in beef or dairy cattle. The present study showed that the increase in milk energy output (measured in MJ) per increase in ME intake (measured in MJ) owing to wilting was linear, with a slope of 0·19. This response from additional ME intake owing to wilting is in line with what would be anticipated when increasing ME intake by other methods.  相似文献   

10.
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.  相似文献   

11.
Our objective was to investigate Lactobacillus buchneri as a silage inoculant or probiotic on in vitro ruminal measurements of low dry‐matter whole‐crop maize silage. In vitro gas production was conducted using untreated (without inoculant) and inoculated (treated with L. buchneri CNCM I‐4323 at 1 × 105 cfu g?1 of fresh forage) maize silages (wet‐ground) incubated with three different ruminal inocula, in a 2 × 3 factorial arrangement. Ruminal fluids were collected from wethers consuming (i) untreated maize silage (RF‐U); (ii) inoculated maize silage (RF‐I); and (iii) untreated maize silage with a daily dose of L. buchneri CNCM I‐4323 administered directly into the rumen (1 × 107 cfu g?1 of supplied silage [LB‐probiotic]). Gas production was consistently higher when inoculated silage was used as the substrate of fermentation, compared to the untreated silage. When untreated silage was used as substrate, the total volatile fatty acid concentration was higher using RF‐I and LB‐probiotic inocula, compared to the RF‐U inoculum, at 9 hr and at 48 hr of fermentation. It is concluded that L. buchneri should be used as a silage inoculant rather than as a probiotic because it alters fermentation within the silo thereby improving silage quality and enabling some benefits for ruminal fermentation.  相似文献   

12.
This study attempted to separate the effects of forage source and field microbiota on silage fermentation quality and aerobic stability. Single samples of grass, red clover and maize were used. Field microbiota was obtained by centrifugation of microbial suspensions of the three samples. The intact forages were dried and sterilized by heating at 60°C for 3 h + 103°C for 15 h, inoculated in a 3 (forage) × 3 (inoculum) design and reconstituted to a dry‐matter level of 400 g kg?1 before ensiling. After ensiling for 71 d, subsamples were subjected to an 8‐d aerobic stability test, which included temperature and pH measurements. Bacterial community analysis was performed on samples before and after ensiling by 16S rRNA gene amplicon sequencing. Forage source had a marked effect on the levels of lactic acid, acetic acid, ammonia‐N and 2,3‐butanediol, but microbiota source only affected the acetic acid concentration. The forage and microbiota as well as their interactions affected silage stability variables. The maize microbiota improved silage stability, whereas silages made from the maize forage had the poorest stability. Bacterial community analysis revealed higher abundance of lactic acid bacteria on the maize forage, with Lactococcus and Leuconostoc being the dominant genera. These preliminary results suggested that fermentation quality is mainly affected by forage source, whereas the aerobic stability is affected by both forage and field microbiota.  相似文献   

13.
Abstract To counteract a decrease in the availability of grazing for feeding dairy cows in France, a simulation model is proposed in the paper, which combines decision and agronomic submodels to study forage system management strategies compatible with spring grazing use. Nine strategies were tested with the model using a sequence of 16 climatic years. Three of these strategies come from a survey in south‐west France and six others were designed with research scientists or farm advisors. The strategies differ in the duration of maize silage feeding, the area dedicated to maize silage and the area dedicated to grass silage. Results from simulation models show that the consequence of a large and constant maize silage area is a high maize silage overstock if there is an early turnout or a high grass silage overstock if turnout is late. The consequence of a low maize area is a high grazing duration combined in some years with feeding shortages. Strategies that have no feeding shortage and a low level of maize and grass silage overstock have a high grazing duration and have no constant maize or grass silage areas. The solution proposed to avoid climatic risk, and its consequences on feeding, is based on two procedures: use of reserve areas for production and allowing the production programme to be modified to take into account fresh information, especially weather records.  相似文献   

14.
A database containing 140 articles published in journals (731 treatment means evaluated) was used to examine the effect of different lactic acid bacteria (LAB) on fermentation, chemical composition and aerobic stability of maize (corn) silage. Compared with the control, dry matter (DM) loss increased by 8% and 50% (p < .01) due to inoculation of maize silage with either homolactic LAB (hoLAB) or heterolactic LAB (heLAB). In vitro DM digestibility of maize silage increased only with hoLAB inoculation (+2.22%; p < .01). The heLAB inoculation increased (p < .01) the aerobic stability of maize silage by 71.3 hr. To investigate the effect of silage inoculation on livestock production, a second database comprising 35 articles [99 treatment means evaluated based on results from 648 cattle (429 beef cattle and 219 dairy cows) and 298 sheep] was used. Inoculation of maize silage with either hoLAB or heLAB did not affect milk yield (p > .05), but their combination (mixLAB) depressed milk yield (–2.5 kg/day; p < .01). Inoculation with hoLAB increased DM intake in sheep (+0.15 kg/day; p = .02), but decreased it in beef cattle (–0.26 kg/day; p = .01) without affecting average daily gain for both sheep and beef cattle (p ≥ .06). In conclusion, fermentative loss increased regardless of the bacterial inoculant used, while aerobic stability increased mainly by using heLAB. Benefits from hoLAB inoculation on animal performance were noted only for feed intake in sheep, while productive performances of dairy cows and beef cattle were not improved.  相似文献   

15.
The difficulty in matching the herbage requirements of grazing dairy cows to herbage production, due mainly to the unpredictability of the latter., causes stocking rates to be too low for maximum per hectare production and, thus, cows to be underfed at certain times in the grazing season. Conserved forage may be used as a supplement for grazing dairy cows in order to reduce variation in forage intake by the cow, to allow pasture stocking rates to be increased and to increase the efficiency of land use. The effect of offering conserved forage with herbage on intakes and production is reviewed in comparison to both ad libitum and restricted herbage. Total nutrient intakes and milk fat + protein yields are reduced for cows offered herbage and supplementary forage compared with cows offered ad libitum herbage, but increased compared with cows offered a restricted herbage level. Increasing pasture stocking rates may allow increases in utilized metabolizable energy levels from grassland but further research is needed in this area. Both grass and maize silage supplements offer potential for increasing the efficiency of land use, but in the case of grass silage this is only achieved in the best management practices.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
Forty‐eight high‐yielding dairy cows of the Swedish Red breed were used to examine the effects of providing pea–oat silage (P), grass–clover silage (G) and a 0·50:0·50 mixture of the silages (M) ad libitum in diets with two concentrate levels (7 or 10 kg d?1). A 9‐week experiment, including a 2‐week pre‐experimental period in which the cows were all fed the same diet, and an in vivo apparent digestibility study were conducted comparing the six dietary treatments (M7, M10, P7, P10, G7, G10). Intake and digestibility of the diets and milk production and live weight of the cows were measured. The G silage [11·3 MJ ME kg?1 dry matter (DM)] was first‐cut grass herbage wilted for 24 h prior to addition of an additive, containing formic acid, propionic acid and ammonia, at 4 L t?1 fresh matter (FM). The P forage was cut when the peas were at pod fill and ensiled directly with 6 L t?1 FM of the same additive. The main hypothesis tested, that cows fed the M silage would produce more milk than the cows fed either the P or the G silages, was confirmed. The cows fed the M7 dietary treatment had similar milk yield and milk composition to cows offered the M10, G10 and P10 dietary treatments, and cows offered the G7 and P7 dietary treatments had lower milk and milk protein yields. This suggested that a mixed ration of pea–oat bi‐crop and grass–clover silage has a concentrate‐sparing effect, and that the use of pea–oat bi‐crop and grass–clover silage as a mixed ration for high‐yielding dairy cows can be recommended.  相似文献   

19.
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.  相似文献   

20.
Effects of formic acid, formaldehyde and two levels of tannic acid on changes in the distribution of nitrogen (N) and plant enzymatic activity during ensilage of lucerne (Medicago sativa) were studied. Lucerne [300 g dry matter (DM) kg?1 forage] silages were prepared untreated (control) and with formic acid (4 g kg?1 DM), formaldehyde (1 g kg?1 DM) and two levels of tannic acid (20 and 50 g kg?1 DM) as additives. Inhibition of proteolysis by formic acid was more effective than the other additives during the first 7 d of ensiling. Tannic acid was as effective at inhibiting production of non‐protein‐N, ammonia‐N and free amino acid‐N as formic acid and formaldehyde. However, increased concentrations of non‐protein‐N and free amino acid‐N in silage from day 1 to 35 of ensiling were less with the higher level of tannic acid than that in the control and other additive‐treated silages. Carboxypeptidase lost its activity slowly with increasing time of ensiling. At day 2, it still had 0·79 of the original activity in the control silage. After 21 d of ensiling, high levels of carboxypeptidase activity, proportionately 0·41, 0·49, 0·10, 0·35 and 0·30 of the original activity, remained in the control silage, and silages made with formic acid, formaldehyde, and low and high levels of tannic acid respectively. There were higher levels of activity of acid proteinase in formic acid‐treated silage than in the control silage until day 2 of ensilage indicating that the reduction of proteolysis by formic acid was probably due to acidifying the forage below the pH optima of plant protease. Aminopeptidase activity in all silages declined rapidly after ensiling.  相似文献   

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