Source: UNIVERSITY OF MAINE submitted to
IMPROVEMENT OF SILAGE QUALITY AND ITS UTILIZATION BY DAIRY COWS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0198361
Grant No.
(N/A)
Project No.
ME08306-03
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2003
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Project Director
Stokes, M. R.
Recipient Organization
UNIVERSITY OF MAINE
(N/A)
ORONO,ME 04469
Performing Department
ANIMAL & VETERINARY SCIENCES
Non Technical Summary
Many silage additives are marketed with very little scientific evidence to support their efficacy. Effects of many additives can be determined in small-scale silos but these may not truly represent farm silo conditions. We will construct pneumatic packers for laboratory and small-scale silos to make laboratory data more representative of farm-scale ensilage. Commercial silage additives will then be evaluated to provide useful information to producers.
Animal Health Component
70%
Research Effort Categories
Basic
(N/A)
Applied
70%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3021699101050%
3023499101030%
3027299101020%
Goals / Objectives
To improve our capabilities to perform laboratory-scale investigations with mini-silos, tube-silos, and tube-silos modified to allow the collection of effluent. To continue to investigate the effects of cell-wall degrading enzyme products and other silage additives, such as inoculants and organic acids, on silage fermentation, composition, effluent production and performance of lactating dairy cattle. To investigate the effectiveness of any enzyme-based feed additive for ruminants that is marketed in Maine in the next five years.
Project Methods
A pneumatic silo packing system will be developed to pack laboratory-scale mini-silos to a density similar to the average density achieved in farm-scale silos and to pack them to a more uniform density than is possible by hand-packing. We postulate that more uniform packing to the appropriate density will reduce the variation in the fermentation and compostition results of mini-silo investigations. If this is successful then a larger system will be developed for packing meter-long PVC tube-silos and tube-silos that have been modified to collect silage effluent. We postulate that variation in packing density is a major cause of variablity in in effluent production from these silos. Variation in the usual silage fermentation and composition variables from hand-packed silos will be compared to the variation in pneumatically packed silos. The effects of commercially available silage additives on silage fermentation, composition and aerobic stability will be determined after ensilage of corn, grass, or legume forages in laboratory-scale or PVC tube-silos. These effects will also be determined for some silage additives using farm-scale bunker silos with evaluation of silage nutritive value using lactating dairy cattle. The effects on animal performance of any enzyme-based feed additives for ruminants that become available within the next five years will also be evaluated using lactating dairy cattle.

Progress 10/01/03 to 09/30/09

Outputs
OUTPUTS: Experiments were performed to measure the fermentation temperature profile of corn silage harvested in October or November with or without different types of bacterial inoculants and ensiled in 80 ton bunker silos. The same forage was also ensiled in laboratory-scale mini-silos to compare the composition and fermentation profile of the bunker silages to that produced in the mini-silos. Mini-silos were fermented in three different locations to try to simulate the fermentation temperature profile of the bunker silos in the mini-silos. The fermentation in mini-silos of clean forage taken from inside the pile dumped by the forage wagon was compared to that produced by forage taken from the top two inches of the forage mass after it had been leveled and packed by the packing tractor. This forage was considered to be dirty as it would also contain any organisms present on the wheels of the packing tractor that is used for many other jobs around the farm. A hydraulic packer was constructed to safely pack laboratory-scale mini-silos to reduce variability in packing density between mini-silos packed by hand, to allow compaction to a constant level, and to allow mini-silos to be packed to the same density found in bunker silos. This research was discussed with attendees of two International Silage Conferences in Belfast, Northern Ireland and in Madison, WI. The use of different types of silage inoculants was discussed with dairy producers at a Cooperative Extension workshop on forage quality and the importance of forage quality was discussed with deer and elk producers at their annual meeting. PARTICIPANTS: Individuals involved with this project included: Principal Investigator, Professor Martin R. Stokes as project director. Research Technician, Richard Seekins, assisted with ensilage in mini-silos, sampling of forage during farm ensiling and during farm feed out of silage, feeding experimental dairy cows, analysis of samples in research laboratory. Graduate Assistants, Na Wang and Carolyn Gilman, assisted with ensilage, sampling, analysis of samples and of data. Partner Organizations, Lallemand Inc. and Chr. Hansen Inc. both provided funds to partially support this research. Training or Professional Development, assistance with these projects was used as undergraduate research opportunities for four University of Maine undergraduates in the Animal and Veterinary Sciences degree program. TARGET AUDIENCES: Maine dairy producers were targets of this research to allow them to make higher quality forages and to sample them correctly for analysis. Academic and industry researchers were targets of the mini-silo research to aid them in more successfully simulating farm-scale silage fermentations in the laboratory. Efforts to transmit this information to producers was by oral presentations and to industry by project reports. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Comparison of bunker silage fermentations with those in small laboratory-scale mini-silos indicated that bunker silage fermentation of late cut corn silage cannot be duplicated in a research laboratory where the room temperature is thermostatically controlled. Simulation of the rapid heating to peak temperature followed by a slow cooling over weeks or months requires fermentation in either a temperature-controlled incubation room or in a bench-top incubator of sufficient size to hold the required number of mini-silos. Academic or commercial industry researchers will thus need to modify their fermentation protocol when using mini-silos to develop silage additives for corn silage for use in northern states. This should not be a problem in warmer states or when forage is harvested earlier in the year. There also may be little difference in the fermentation of bunkers versus mini-silos for first, second or third cut hay-crop silage or alfalfa harvested in Maine in June through August. Geographic location may also be of less importance for these crops. Fermentation in mini-silos, irrespective of temperature profile, produced a more extensive and more homolactic fermentation than fermentation of the same forage in a bunker silo. This may have been due to them being packed to a higher density than is typically achieved in an 80 ton bunker silo. Using a hydraulic packer that allows mini-silos to be packed to a constant density should remove some of the variability between mini-silo replicates. Packing mini-silos to the density found in bunker silos should also allow the mini-silo composition to more closely reflect the composition in a bunker silo. The importance of forage source for use in mini-silos and the temperature at which they are fermented may require changes in action by researchers so that mini-silo data more closely resembles that found in bunker silos. While composition differences between control and inoculated bunker silages were relatively small, larger and more significant differences were found between samples taken from the top half versus the bottom half of the bunkers. A more extensive and more homolactic fermentation occurred in the bottom half of the bunker silos as judged by silage pH and the concentrations of fermentation acids. This change in knowledge will be stressed to dairy producers since inappropriate sampling of their bunkers could affect the results of chemical analyses to predict silage energy content and nutritive value for feeding their animals. This could require a change in action by dairy farmers to sample correctly.

Publications

  • No publications reported this period


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: OUTPUTS: Statistical analyses have been continued to compare the fermentation and composition of corn silage fermented in 70 ton bunker silos with data from fermentation of the same forage in laboratory-scale mini-silos at three fermentation temperature profiles. PARTICIPANTS: PARTICIPANTS: Martin Stokes, Principal Investigator; Richard Seekins, Research Technician. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Measurement of corn silage fermentation temperatures in bunker silos with miniature data-loggers showed that peak temperature and fermentation profile varied considerably between additive treatments, between silos, and at different locations within the silo. The accumulated temperature rise of silage inoculated with a mixture of homofermentative and heterofermentative bacteria was greater than the temperature rise of silage inoculated with homofermentative organisms and both were higher than the control, which was unexpected. The inoculated silages appeared to cool down less and more slowly than did the control silage as the winter progressed. Inoculation of corn forage with Lactobacillus buchneri 450 (Lallemand, Inc.) tended to increase bunker silage pH and reduce lactic acid concentration and the ratio of lactic acid to acetic acid (all P<.08 to .10). Other fermentation variables were unaffected. The treated silage took longer to spoil but the difference, 1.4 days, was much smaller than literature reports for other studies performed with L. buchneri. The organism I used may be a different strain to that reported in the literature. It is not yet possible to define the best protocol to simulate bunker silo fermentation of corn forage in mini-silos. However, to more accurately represent farm-scale fermentations, laboratory-scale experiments should be performed at the same silage density as the bunker silo and should follow a similar fermentation temperature profile. Fermentation of mini-silos in a laboratory with thermostatically controlled heating cannot simulate the temperature profile or fermentation profile of a farm-scale silo exposed to declining ambient temperatures as winter approaches. The temperature of fermentation may be of less importance for crops harvested in the summer when the ambient temperature is higher and there will be smaller differences between silage temperature in the bunker, the surrounding ambient temperature, and the temperature in a laboratory. Thus, the fermentation temperatures of summer harvested haylage crops ensiled in bunker silos need to be determined and the silage fermentation and composition in bunker silos must be compared to those of silage fermented in mini-silos in the laboratory. These outcomes may impact forage research by requiring a change in action by researchers using laboratory-scale mini-silos to predict farm-scale silage composition, particularly in the testing or development of silage additives.

Publications

  • No publications reported this period


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Chemical and statistical analyses continued to compare the effects of Lactobacillus buchneri 450 inoculation to untreated control fermentations on the composition of bunker silage and to compare these silages to those produced in laboratory-scale mini-silos fermented at three temperature profiles using either clean, unpacked forage or "dirty forage" that had been packed by the tractor and which could have been contaminated with microorganisms from the tractor wheels. Information on silage research was presented to producers as an invited speaker at the Maine Dairy Industry Seminar, presentation entitled Animal and Veterinary Sciences, Past, Present and Future, March 13, 2007, and as an invited speaker at the New England Deer and Elk Farmers Association Annual Conference, presentation entitled Forages for Deer and Elk, April 21, 2007. PARTICIPANTS: Martin Stokes. Principal Investigator. Na Wang. Graduate Assistant. Carolyn Gillman, Graduate Assistant. Richard Seekins, Research Technician. Undergraduate students Nelson Noel, Stephanie Beamish, Sarah Cady, and Ashley Bubar received training in this project by using different aspects of it for their senior research projects. TARGET AUDIENCES: Scientific presentations were made to Maine dairy producers and to New England deer and elk producers to aid them in their forage management. Undergraduate students received experiential learning opportunities in their senior project research.

Impacts
While composition differences between control and inoculated bunker silages were relatively small, larger and more significant differences were found between samples taken from the top half versus the bottom half of the bunkers. A more extensive and more homolactic fermentation occurred in the bottom half of the bunker silos as judged by silage pH and the concentrations of fermentation acids. This change in knowledge will be stressed to dairy producers since inappropriate sampling of their bunkers could affect the results of chemical analyses to predict silage energy content and nutritive value for feeding their animals. This could require a change in action by dairy farmers to sample correctly. Numerous interactions were observed between inoculation treatment and the use of clean or dirty forage and between the forage type and the temperature profile of the laboratory-scale fermentations. The main effect of inoculation on fermentation profile was relatively small but using dirty forage increased the lactic acid and total acid concentrations with or without inoculation. Dirty forage increased the acetate concentration in the control treatment but decreased the concentration when inoculated. Similarly, dirty forage reduced the lactate to acetate ratio of the control but increased it when inoculated. The coolest temperature profile also interacted with the effects of inoculation and forage source but irrespective of inoculation produced silage containing the least titratable acidity, lactic acid, acetic acid, total acid concentration and ammonia, with the highest lactate to acetate ratio. As observed previously, fermentation in mini-silos, irrespective of temperature profile, produced a more extensive and more homolactic fermentation. The importance of forage source for use in mini-silos and the temperature at which they are fermented may require changes in action by researchers so that mini-silo data more closely resembles that found in bunker silos. The fermentation temperature profile of crops ensiled in mini-silos in the warmer months of the year may not need to be modified since indoor and outdoor ambient temperatures can be more similar than for corn silage harvested in the fall and fermented as outdoor ambient temperatures are decreasing. Fermentation comparisons of summer harvested crops need to be researched.

Publications

  • No publications reported this period


Progress 10/01/05 to 09/30/06

Outputs
The effect of Lactobacillus buchneri 450 on corn silage fermentation temperature and composition was determined in 40 tonne bunker silos ensiled on different days to avoid contamination of the control forage with the inoculant. Silage temperature was measured for 144 days at 6 locations half-way into the silo at one third and two thirds of forage depth. The second day of harvest was cooler than the first so initial forage temperature (26.62 vs 22.50 C, P<.001) and peak fermentation temperature were lower (31.30 vs 29.38 C, P<.001) for the inoculated forage but the temperature rise was greater for the inoculated forage (4.68 vs 6.88 C, P<.01). Temperature rise was also greater in the top third of the silo compared to the bottom third (6.67 vs 4.90 C, P<.01). Mean fermentation temperatures did not differ (19.90 vs 21.71 C, NS). Silage was sampled twice monthly from the bottom third and top third of each silo during feed out. Inoculated forage was damper than the control (29.12 vs 26.86 %DM, P<.01) but silage pH, titratable acidity and fermentation acids were not affected. Silage from the top third vs bottom third of the silo face had lower lactic acid concentration (2.36 vs 4.81%, P<.001) and lactic to acetic ratio (.66 vs 1.70, P<.001), increased butyric acid level (0.10 vs 0.03%, P<.05) and tended to have a higher pH (4.17 vs 4.04, P<.06) and lower total acid concentration (7.81 vs 9.21%, P<.10). Silage from the bottom third of the silo however had increased DM, CP, ash, P, K, S and sugar contents and reduced hemicellulose compared to samples from the top third of the silo (P<.001 to .035). On each harvest day, mini-silos (137 g forage) were packed to a density of 592 kg/cu.m to compare the effects of inoculation and of using clean unpacked forage with forage taken from the surface of the silo after packing, which could have a different microbial population due to contamination from the packing tractor wheels. Mini-silos were fermented in three different locations to produce three fermentation temperature profiles (hot 5 d with warm 67 d, warm 72 d, and hot 5 d, cold 67 d). Temperature variables did not differ due to inoculation or the source of the forage (clean or dirty) but maximum and mean temperatures were lowest for the hot-cold temperature profile (max. 27.80, 26.54, 25.92 C, P<.01; mean 22.05, 21.74, 6.92 C, P<.001). As in the bunker silages, inoculated silage was damper than the control (32.45 vs 31.09 %DM, P<.01) and had a higher pH (3.81 vs 3.92, P<.01). Inoculation had no main effect on lactic acid concentration but increased it more with the dirty forage (P<.01). Acetate level was increased by inoculation only with the clean forage and with the two warm profiles (P<.01). Inoculation increased total acid concentration more with clean forage than with dirty (P<.05). Dirty forage produced more acid at all temperature profiles, but the increase was less marked with the hot/cold profile. Silage ammonia concentrations were only affected by temperature profile (P<.001). Bunker silo fermentation data will be compared to that from the mini-silos to determine which mini-silo protocol best predicts bunker silo fermentation.

Impacts
The source of forage and the temperature profile during its fermentation in mini-silos influences the results compared to fermentation in a bunker silo. Different protocols may need to be followed in different seasons or geographic locations to more closely resemble farm-scale conditions in the laboratory.

Publications

  • No publications reported this period


Progress 10/01/04 to 09/30/05

Outputs
A pneumatic laboratory-silo packing device designed for efficiently and uniformly packing laboratory silos was constructed, tested, and used to investigate how silo forage density impacts silage composition. Efficiency was determined by packing 15 280-mL laboratory mini-silos using three different methods: one by hand with un-weighed forage, one by hand with pre-weighed forage, and one by the packing device with pre-weighed forage. The time required to fill each silo was recorded. Average packing time per silo for each method was 1.80, 1.97, and 1.21 minutes, respectively. Average density, also respectively, varied between silos by 10 %, 4%, and .1%. Testing the importance of consistent densities was accomplished by ensiling whole plant corn at densities of 400 kg/m3/, 560 kg/m3, 721 kg/m3, and 881 kg/m3 in 16 laboratory-scale mini-silos with four silos representing each density. After 58 days of fermentation the silage was removed and analyzed. Initial forage density significantly affected final silage composition. Silage pH, acetic acid, and acid detergent fiber (ADF) decreased directly as density increased; sugar and the lactic to acetic ratio increased directly with density; and titratable acidity, lactic acid, total volatile fatty acids, hemicellulose, neutral detergent fiber (NDF), degradable protein, and soluble protein showed a negative quadratic relationship to density. Whole plant corn was harvested on October 10 and 11, 2004 one week after a killing frost, to compare to a control the effects of a 2 specie homolactic inoculant (BiomaxR 5) and of an inoculant containing both a homolactic and a heterolactic specie (Test Inoculant) on fermentation quality, fermentation temperature profile, aerobic stability and nutritional value when fed to 30 lactating dairy cows over a 6-month feeding period. The treatments were ensiled sequentially, Control, BiomaxR 5 , Test Inoculant, with sanitation of the harvesting, transport and packing equipment between application of the two inoculants to prevent cross-contamination of the Test Inoculant forage with BiomaxR 5 bacteria. Neither inoculant significantly modified silage fermentation parameters although BiomaxR 5 numerically reduced lactic and acetic acid contents and total acid content by 12, 33 and 18 % respectively. The test inoculant reduced these variables by 25 to 28 %. Fermentation temperature profiles were very variable both within and between silos. Maximum temperature reached and temperature after 72 d was lower for the inoculants than the control (P<.02) and maximum temperature of the test inoculant silage was lower than that of the BiomaxR 5 silage. Both TDN and the net energy for lactation were affected by treatment (P<.05) with the test inoculant silage being lower than BiomaxR 5 silage. Both inoculant treatments increased the aerobic stability of the silages and the TMR made from those silages (P<.01). Lactation performance over a six month feeding period was not significantly improved by either treatment but DMI and 3.5% FCM yield were increased by .74 kg/d and 2 kg/d respectively by BiomaxR 5 and by .93 kg/d and 1.7 kg/d by the test inoculant.

Impacts
Research mini-silos should be packed at densities between 560 and 721 kg/m3 to represent normal farm practice. A two specie inoculant and a mixed homo/hetero inoculant could increase silage bunk life and make an economic increase in milk production on a farm-scale.

Publications

  • No publications reported this period


Progress 10/01/03 to 09/30/04

Outputs
A pneumatic silo packing system to fill laboratory-scale silos made from 250ml measuring cylinders has been constructed and is being tested for safety and to develop a Standard Operating Procedure with Hazard Assessment and Safety Procedures. A review of the literature suggests that silages vary in density from 144 to 1041 kg/cu m, mean value 640 kg/cu m. Across 18 experiments performed in our laboratory in 250 ml mini-silos, density varied from 464 to 1217 kg/cu m, mean 1057 kg/cu m, which suggests that, on average, laboratory-scale silos are packed more densely than farm-scale silos. Variation within experiments varied from 15 to 33 %. An experiment with inoculated corn forage will be performed to determine the effect of silage density on silage fermentation quality. Data-loggers placed in a bunker of corn silage showed that fermentation temperature peaked in five days at 28.4 degrees Celsius and then declined as the winter got colder. In contrast, the temperature of corn forage ensiled in canning jars in a laboratory peaked at 28.0 degrees Celsius in about 3 days and then followed changes in laboratory ambient temperature caused by the heating system. Insulating the silos inside boxes of R-10 or R-20 foam insulation increased the initial fermentation peak temperature to about 29.5 degrees Celsius and delayed the changes in silo temperature with changes in ambient but the pattern was the same. For all treatments the temperature tended to increase as we progressed into winter. Fermentation temperature profile markedly affected silage fermentation quality. The laboratory-scale silages contained significantly less lactic acid (4.5 - 5.3 %DM) and more acetic acid (3.0 - 3.7 %DM) than the bunker silage (9.4 % lactic and 1.9 % acetic) with little effect on pH (4.0 vs 3.8). The ratio of lactic to acetic acids was thus lowered from 5.2 to approximately 1.5 An experiment with laboratory-scale corn silages is in progress to compare the fermentation temperature profile and fermentation analyses of silos fermented in three locations with different temperature profiles designed to mimic more closely in lab-scale silos the temperature profile of a bunker silo. Three 40 tonne bunker silos have been filled with corn forage to compare to a control the effects of a 2 specie homolactic inoculant and of an inoculant containing both a homolactic and a heterolactic specie on fermentation quality, fermentation temperature profile, aerobic stability and nutritional value when fed to 30 lactating dairy cows over a 6-month feeding period.

Impacts
If a protocol can be defined for fermenting laboratory-scale silos to more closely represent temperature and density conditions of a bunker silo then more useful data can be generated on silage additive effects to predict farm silo performance.

Publications

  • No publications reported this period