Milk Production from Cows Fed Corn, Alfalfa, or Ryegrass Silage Ensiled in Conventional, Vacuum, or Packed Systems

The Professional Animal Scientist Moss et al. 18 (2002):324–331

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from Cows Fed MilkCorn,Production Alfalfa, or Ryegrass Silage Ensiled in Conventional, Vacuum, or Packed Systems B. R. MOSS,*,1 PAS, DPL ACAN, J. C. LIN*, PAS, D. WRIGHT†, L. WRIGHT†, W. H. MCELHENNEY*, J. W. PREVATT#, and H. D. DOROUGH‡ *Animal Sciences Department, Auburn University, AL 36849; †Canebrake Farms, Alexandria, AL 36250; #Agriculture Economics and Rural Sociology Department, Auburn University, AL 36849; ‡Alabama Cooperative Extension System, Talladega, AL 35160

Abstract Temperature of alfalfa silage was monitored for 28 d at three depths following ensiling in a vacuum bag system. For this silo system, silage was piled on one sheet of plastic and covered by another; the plastic sheets were connected on all sides by rolling and clamping around a polyvinylchloride pipe. The silo was evacuated with a vacuum pump attached to a perforated pipe placed on the bottom sheet of plastic prior to filling. Temperatures increased linearly as depths increased (0.3 to 0.6 and 0.9 m), but temperature measurements were <35.9oC at all depths. Storage cost per ton of silage ensiled was very sensitive to the quantity ensiled and marginally sensitive to DM losses. For a vacuum silo with 40 metric ton (mT) (DM) capacity, storage cost estimates per mT (DM) were $8.90, $9.50, $9.95, and $10.44 for 5, 11, 15 or 19% DM losses, respectively. Temperature differences attributable to post-ensiling days were detected. The performance of 48 midlactation (187+ 45 d in milk) cows

fed diets based on forages (45.8 to 61.4% DM) of corn (CS), alfalfa, or ryegrass silages (RS) with or without 7.0% cottonseed hulls (CSH) was compared in a 75-d lactation trial. Corn silage was ensiled in an upright silo; alfalfa silage was ensiled in both an Ag-Bag® (Ag-Bag International, Warrenton, OR) and vacuum bag system (BAL and VAL, respectively); RS was ensiled in an AgBag® system. Cows fed CS without CSH produced more milk (21.1 kg/d) than did cows fed the other three silages (17.1 to 19.1 kg/d). No differences in milk production were detected for cows consuming silage from the different ensiling systems, indicating that the vacuum ensiling process can be a satisfactory method of making silage. Cows fed RS consumed less DM (11.0 to 12.1 kg/d) than did cows fed the other three silages (14.4 to 20.4 kg/d). Inclusion of CSH in the alfalfa silage-based diet increased DMI, milk production, and BW gain but had no effect on milk fat or protein percentage. A vacuum silo system may be a satisfactory method of ensiling crops, especially during emergency situations, for short-term ensiling, and for small herds.

1To whom correspondence should be addressed: [email protected] (Key Words: Vacuum Silage, Silage

Systems, Silage, Dairy Cows, Milk Production.)

Introduction Obtaining quality forage is a challenge under favorable conditions and is even more difficult in humid climates. Harvesting and storing hay crops as silage are not affected as much by adverse climatic conditions as are haying procedures. However, many operations are not properly equipped to store silage with conventional systems. Various approaches to ensiling crops have been developed, but many systems are expensive and are not suitable for emergency conditions or the small producer. Crops have been ensiled with a vacuum system, but data on this system or silage from the system are limited. Promma et al. (15) used vacuum ensiling in polyethylene bags for small research samples and found that the system effectively prevented secondary fermentation. Achacoso et al. (1) reported an advantage for ensiling corn silage (CS) via evacuation of air compared with conventional packing and sealing in steel

Ensiling with a Vacuum System

drums. Melotti and Velloso (11) found that a vacuum silage system was an effective means of ensiling 8 metric ton (mT) of elephant napier grass with the addition of 3% molasses. Vacuum ensiling systems of varying sizes have been used under farm conditions in Australia (F. Michan, 2000, Dep. Natural Resources Environ., Ellinbank, Victoria, 3821 Australia, personal communication), New Zealand (R. Plank, Dep. Agric. Natural Resources, Berea College, KY, personal communication), Thailand (B. R. Moss. unpublished data), and the U.S. (9, 12). Guyer (6) stated that vacuum ensiling was difficult to accomplish with larger silos, presumably because of the sealing of the silo, but specifics on the size were not given. On-farm storage of 50 to 80 mT silage has been accomplished under the Australian conditions. In many areas of the Southeast U.S., cottonseed hulls (CSH) are often the primary source of roughage or are used to extend conventional forage supplies. The energy and protein contents of CSH are low, but the high fiber content and ease of mixing (4) make it a good roughage source. Incorporating CSH into diets often increases DMI whether used as a forage extender (4) or as the primary forage source, but data on use with alfalfa hay or silage are sparse (4, 7). The primary objective of this study was to evaluate vacuum-ensiled silage and compare silages from this system with those ensiled under conventional methods when fed to lactating cows with or without CSH additions.

Materials and Methods Silos and Temperature Evaluation. In early August, alfalfa (28% DM) was direct-chopped with a flail chopper into a dump wagon and ensiled loose in two vacuum bag silos. To form the bag, two layers of 12.3- × 30.5-m sheets of 6-mL black plastic were laid out, and both sheets were wrapped and clamped around a 33.5-m × 5.1-cm polyvinyl chloride

(PVC) pipe (Figure 1A). The top sheet was pulled back, and the opposite side of the bottom sheet was wrapped and clamped around another 33.5-m × 5.1-cm PVC pipe (Figure 1B). The bottom sheet was rolled up to allow about 4.5 m of exposed plastic on the ground. Silage was dumped on the bottom sheet, and eight subsequent loads were overlapped to form a continuous windrow (Figure 1B and C). The bottom sheet was rolled out as needed to provide space for subsequent overlapping of three additional windrows. Prior to dumping the third windrow, 24 m of a perforated 5.1-cm PVC pipe was centered on the lower sheet and attached to 6.5 m of non-perforated pipe. This pipe extended 3 m beyond the plastic silo and was used as a vacuum pipe (Figure 1B and C). Four windrows of eight loads supplied 145 mT (40.6 mT DM) in a 24- × 7.5- to 9- × 2.4-m stack. The top sheet was pulled across the unpacked stack, laid along the bottom sheet, and both sheets were rolled and clamped around the PVC pipe. Both ends of the two sheets were rolled and clamped around a 3-m section of PVC pipe (Figure 1D). The sheets were folded and duct-taped at the corners and at the centered vacuum pipe. The vacuum PVC line was attached to a cut-off valve and then to a flexible line that was connected to a portable milking vacuum pump (Figure 1D). After sealing, oxygen was evacuated from the silos for 15 to 30 min once daily for 21 d. Internal silo temperatures were taken at 0800 h on d 1 through 7 and on d 14 after ensiling. A small hole was cut in the plastic, and a hollow probe with conical end was shoved into the silage to 0.3-, 0.6and 0.9-m depths at three different locations in each bag. A thermocouple was inserted in the hollow probe, and temperatures were recorded. A sample was taken at a 0.3m depth on d 14, 21, and 28 for pH determination. Maximum 24-h ambient temperatures for the region were obtained from the nearest U.S.

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National Weather Service Station (Cullman, AL). Silage storage costs for the vacuum silo were estimated based on different DM losses and silo capacities using the procedure of Cromwell et al. (2). Variable costs were calculated from the price and quantities of plastic, labor, materials procurement and disposal, and operating capital. Fixed costs (depreciation, interest, repairs, taxes, and insurance) were estimated for the PVC materials ($146.00) and the vacuum pump ($1,000). Straight-line depreciation (investment cost minus salvage value divided by the number of years of useful life) was used to calculate annual depreciation. The useful life of the PVC materials and vacuum pump was set on two and seven vacuum silos annually for 3 and 7 yr, respectively. Interest costs were calculated at 9% of the average of investment cost and salvage value. Annual repair costs for the PVC materials were estimated at 1 and 5% of investment cost, respectively. Annual taxes were calculated at 70% of investment costs times the millage rate of $18 per $1,000. Annual insurance costs were estimated at 0.5% of the average of investment cost and salvage value. Costs were calculated for varying capacities with DM losses from 5 to 19%. Lactation Study. A 75-d lactation study was conducted with 48 Holstein cows (187 ± 45 d in milk) at the E. V. Smith Research Center Dairy Unit (Shorter, AL). Animal protocol was reviewed and approved by the Auburn University Institutional Animal Care and Use Committee. Cows were individually fed one of four dietary silage treatments with or without CSH. Silages were CS, alfalfa ensiled in an Ag-Bag® system or in a vacuum system (VAL), and ryegrass silage (RS) ensiled in an Ag-Bag® system. The CS was ensiled in July in an upright concrete-stave silo. The BAL and RS were ensiled in mid-May after wilting for 24 to 48 h. Both alfalfa treatments were from adjoining areas within the same field, but the BAL was ensiled the day after the VAL

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Figure 1. Schematic of vacuum silo. A) Initial layout of silo, B) initial silage placement, C) placement of evacuating pipe and subsequent placement of silage, D) top and bottom plastic wrapped together around polyvinyl chloride pipe on each side of silo.

treatment. Ryegrass and BAL were ensiled with accepted procedures for the Ag-Bag® system in 8.2-m diameter bags. For the VAL treatment, five

vacuum system silage bags were filled in the manner outlined for temperature monitoring, but smaller amounts were ensiled (2.1 × 6.1 m) to

minimize exposure upon feed out of the silage, as there were a relatively small number of cows consuming the silage. The vacuum lines from the

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five silos were interconnected, and the silos were evacuated immediately after ensiling and daily until opened for feeding (49 to 90 d). Silages were sampled and analyzed for DM by drying at 100oC for 24 h. Protein was determined by dry combustion with a LECO CHN-600 Analyzer® (LECO Corporation, St. Joseph, MI). Acid detergent fiber was determined according to the procedures of Robertson and Van Soest (16), and NDF was analyzed according to Robertson and Van Soest (16) as modified by Van Soest et al. (19). Minerals were analyzed by inductively coupled plasma spectrophotometer (ICP 61®; Thermo Elemental Corporation, Franklin, MA). Acetic, butyric, and lactic acid concentra-

tions in silage were determined by gas chromatography following the procedures of Umana et al. (20). The lactation study started in mid June, 40 d after ensiling the alfalfa silage. Treatment diets (Table 1) were fed as a total mix. Diet composition was based on initial analyses of the forages and NRC (14) values for other feeds. Daily feed consumption was determined for each cow. Cows were milked twice daily at 0100 and 1300 h and housed in tie-stalls within an open barn, but were on an outside exercise paddocks from 0800 to 1100. Milk weights were recorded daily, and individual alternate a.m.-p.m. milk samples were taken at 14, 45, and 74 d for milk fat and protein analyses by infrared procedures (Foss 360®; Foss

TABLE 1. Ingredient and nutrient composition of treatment dietsa. + CSH

– CSH

CS

BAL

VAL

RS

CS

Ingredient, % DM Silage CSH Cottonseed, whole Ground corn Soybean meal Megalac®b Soyhulls Salt AU mineral Dynamate®c

51.3 7.0 12.5 10.0 14.7 2.0 10.0 0.1 2.4 0.0

50.0 7.0 12.5 15.5 0.4 2.0 10.0 0.0 2.5 0.0

45.8 7.0 12.5 5.7 0.0 2.0 25.0 0.0 2.1 0.0

46.1 7.0 12.5 10.0 5.3 2.0 24.3 0.0 2.6 0.1

Content DM, % CP, % DM NEL, mcal/kg NDF, % DM ADF, % DM NSC, % DM Ca, % DM P, % DM

47.8 17.7 1.72 45.9 25.5 25.6 0.95 0.38

79.6 17.7 1.65 42.9 29.4 26.5 1.34 0.38

61.8 17.7 1.65 47.4 33.7 22.1 1.27 0.38

47.6 17.7 1.65 50.7 34.1 18.1 1.23 0.38

aCSH

BAL

VAL

RS

58.8 58.3 0.0 0.0 12.5 12.5 0.0 5.6 14.4 0.0 2.0 2.0 10.0 19.2 0.1 0.0 2.3 2.4 0.0 0.0

59.0 0.0 12.5 0.0 0.0 2.0 25.1 0.1 1.4 0.0

61.4 0.0 12.5 0.0 2.4 2.0 19.0 0.1 2.5 0.2

44.8 17.7 1.65 43.3 22.0 27.9 0.93 0.38

56.5 19.7 1.65 45.9 32.6 20.5 1.24 0.38

41.1 17.7 1.65 47.9 31.7 19.7 1.26 0.38

78.1 18.9 1.76 45.7 30.2 21.7 1.43 0.38

= Cottonseed hulls, CS = corn silage, BAL = alfalfa ensiled with AG-Bag® (AgBag International, Warrenton, OR) system, VAL = alfalfa ensiled with vacuum system, and RS = ryegrass ensiled with AG-Bag® system. bCommercial source (Church & Dwight Co., Inc., Princeton, NJ) of rumen bypass fat. cCommercial source (IMC Global, Lake Forest, IL) of Mg and K sulfate.

Feed Technology, Inc., Minneapolis, MN) at the Southeast Dairy Herd Improvement laboratory (McDonough, GA). Cow BW was taken on 2 consecutive d prior to the study, at d 45 and 46, and at the end of the study. A heparinized jugular vein blood sample was collected from each cow prior to a.m. feeding on d 65. Samples were placed on ice and centrifuged (3,500 rpm) within 2 h for 20 min. Plasma was removed and stored at –20oC until analyzed for urea nitrogen (PUN) by a quantitative Urease/Berthelot determination (Procedure no. 640; Sigma Diagnostics, St. Louis, MO). Statistical Analysis. The experiment was a completely randomized design wherein treatments were arranged as a factorial with two CSH levels and four forage sources (FS). The General Linear Models procedures of SAS (17) were used to analyze all data. When significance (P<0.05) or trends (P<0.10) were declared, the PDIFF option was used to compare treatment means. When the interaction effects between FS and CSH levels were important (P<0.10), pre-planned contrasts were used to determine the nature of the interaction. The statistical model was Yijk = µ + Fi + Cj + FCij + eij where Y = response variable, µ = overall mean, F = FS effect, C = CSH level effect, FC = forage × CSH interaction effect, and E = error term.

Results and Discussion After the materials were obtained and cut to length, setting up the silo for filling required about 0.5 h for two people who had previous experience with the system. Closing the silo required a similar amount of time. Brisk winds could challenge closure. An actual evacuating time of 15 min was adequate, but evacuation was often longer if conducted in conjunction with other work. Temperature Evaluation. Internal silo temperatures increased (P<0.05) linearly as depth increased with

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TABLE 2. Temperatures (least squares means) and pH following ensiling in vacuum bags. Silage Ambient Silage Day (°C)a maximumb (°C) pH 1 2 3 4 5 6 7 14 21 28 SE

38.0 37.6 37.3 31.7 33.7 34.1 35.8 33.7 — — 0.71

30.8 29.4 25.8 20.3 23.3 29.2 30.8 31.1

4.76 4.64 4.52

aDifferences caused by days after ensiling were detected (P<0.01). Temperatures were cubically (P<0.05) related to days after ensiling using orthogonal contrasts. bU.S. National Weather Service 24-h maximum at 1.5 m.

values of 34.5°C, 35.3°C, and 35.9°C (SE = 0.19) at depths of 0.3, 0.6, and 0.9 m, respectively. These differences were minimal and within the range considered normal for silage (10). Ambient temperatures, silo temperatures, and silage pH values are presented in Table 2. Silage temperatures, as determined by regression analysis, solving for the maxima and minima, decreased from the day of ensiling until it reached a minimum at 4.8 d and then increased to a maximum temperature at 10.8 d. These values probably related more to a similar trend in ambient temperatures than the silage fermentation process. The pH values from 4.76 to 4.52 on d 14 through 28 are normal for alfalfa silage (8). Storage Cost. The variable and fixed costs totaled $338.14 for the vacuum silo (Table 3). The total storage cost was used to evaluate the sensitivity to the amount ensiled at varying DM losses (Table 4). The DM losses were not determined in this study, but effluent run-off was

minimal. Silage DM losses vary widely regardless of the silo type with 5, 12, and 15% losses considered average for bags, concrete bunker, and trench silos, respectively (18). Assuming a 5% DM loss, storage cost of the silage in this study (40 mT DM) was $8.90/mT (DM). Storage cost would increase to $9.50, $9.95, and $10.44 with DM losses of 11, 15, and 19%, respectively. These costs are less than estimates of $10.46 for a concrete bunker, but more than for a trench silo ($5.60) with 87-mT (DM) capacities and considerably less than for bagged silage ($31.00) with 191 mT (DM) bagged per year (18). As with other types of systems (18), storage cost per vacuum unit was very sensitive to the quantity ensiled and only marginally sensitive to DM loss. Therefore, filling the vacuum silo to capacity results in substantially lower storage cost per unit. Others (9) have also reported less cost for ensiling with a vacuum system than with other ensiling systems. Although not included in storage cost estimates, ensiling with a vacuum system does not require a person and equipment for packing normally required for trench and bunker silos.

Lactation Study. Nutrient values of the crop silages (Table 5) were typical of good quality silage for the different crops, although the lactic and acetic acid contents were low. The BAL was much drier than the other silages, but the nutrient content (DM basis) of the two alfalfa silage sources were similar. Because of the wide variation in nutrient content of the silages and in an attempt to maximize the amount of silage used in the diets (Table 1), some variation existed in energy and protein contents of the diets. Nitrogen content of all diets was increased to that supplied by the RS treatment to minimize any possible differences in dietary nitrogen. Energy content was greater in the CS diets, but the energy supplied in other diets was adequate for the milk production at the start of the study (14). Differences in CP, fiber, and minerals between the alfalfa silages, CS, and RS are consistent with known nutrient differences, relevant to stage of maturity at harvest between legume and grass silages (13). The first VAL silo was opened within 40 d of ensiling, and the last was opened at about 90 d after

TABLE 3. Storage cost estimates per vacuum silo. Item

Unit

Variable Plastic (black, 6 mL, 12.3 m x 30.5 m) Labor Material procurement & disposal Operating interesta Subtotal Fixedb PVC materials Vacuum pumpc Subtotal Total costs

($/h) ($)

Quantity

Price

2 5 1 130.78

$100.78 $8.00 $20.00 $0.09

Cost

$201.56 $40.00 $20.00 $11.77 $273.33

$29.35 $35.46 $64.81 $338.14

aOperating bFixed

interest was charged for 6 mo. costs include depreciation, interest, repairs, taxes, and insurance for each

item. cThe PVC (polyvinyl chloride) materials and vacuum pump were assumed to be used on two and seven vacuum silos annually for 3 and 7 yr, respectively.

Ensiling with a Vacuum System

TABLE 4. Storage cost estimates [per metric ton (mT)] based on various capacities and DM losses. DM Loss Capacity (mT DM)

5%

7%

9%

11%

30 35 40 45 50

$11.86 $10.17 $8.90 $7.91 $7.12

$12.12 $12.39 $12.66 $12.96 $13.26 $13.58 $13.92 $10.39 $10.62 $10.86 $11.10 $11.37 $11.64 $11.93 $9.09 $9.29 $9.50 $9.72 $9.95 $10.18 $10.44 $8.08 $8.26 $8.44 $8.64 $8.84 $9.05 $9.28 $7.27 $7.43 $7.60 $7.77 $7.96 $8.15 $8.35

ensiling; all bags were vacuumed daily until opened. The silage within each bag was fed out within 2 to 3 wk after opening with care to cover the bags after each day’s feeding. All silage removed had a good visual appearance and a normal silage odor. Specific effects of longer storage, less frequent vacuuming, or tonnage on silage quality is not known. Greater tonnage has been ensiled very satisfactorily with this system (D. Wright, unpublished data), but the tonnage was divided into several smaller silos for this study because of increased

13%

15%

17%

19%

potential for surface spoilage, as the number of cows fed was limited. Popular publications suggest that satisfactory silage was produced without continuous vacuuming under practical conditions wherein only a top layer of plastic was used for sealing (9) or when the silo was sealed with heavier plastic in a manner similar (12) to that used in this study. Intake was least for cows fed RS and greatest for cows fed the BAL diet; similar intakes were recorded for cows fed CS and VAL (Table 6).

TABLE 5. Composition of silages used in lactation study. Silagea Item

CS

BAL

VAL

RS

DM, % CP, % ADF, % DM NDF, % DM Ca, % DM P, % DM TDN, % DM NEL, Mcal/kg DM

32.8 12.4 22.0 51.0 0.20 0.18 67.6 1.54

70.8 22.6 31.0 46.0 0.67 0.28 59.8 1.34

44.6 23.4 31.0 40.0 1.00 0.34 59.8 1.34

30.3 18.3 32.0 48.0 0.63 0.26 61.7 1.41

0.85 0.32 1.48

0.36 0.08 0.64

0.50 0.04 1.61

0.50 0.07 2.37

Volatile fatty acids, % DM Acetic Butyric Lactic aCS

= Corn silage, BAL = alfalfa ensiled with Ag-Bag® (Ag-Bag International, Warrenton, OR) system; VAL = alfalfa ensiled with vacuum system, and RS = ryegrass ensiled with Ag-Bag® system.

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Intake varied widely, but the energy and protein intakes met or exceeded the cows’ requirements (14) except for those fed RS. Contrary to results of other studies (5), CSH inclusion did not increase intake of cows fed the CS diet or have an overall effect on DMI, although intake was numerically increased for cows fed both alfalfa treatments. Regardless of the presence of CSH, cows fed BAL consumed more DM than those fed VAL. Other than DM content, composition of the two alfalfa diets had minimal differences that would account for DMI differences. Despite the differences in DMI and the lack of difference in BW changes, cows receiving VAL and BAL had similar milk production. The addition of CSH to the alfalfa treatments improved milk production, whereas it depressed milk production when included in the CS diet, resulting in a significant forage × CSH interaction. Milk production and DMI of cows fed the RS diets were not affected by CSH inclusion. In contrast to earlier studies (5), CSH did not improve intake of CS, and milk production was depressed for cows fed CS with CSH. This result might have been due to a slight decrease in energy intake for cows fed the CS with CSH. No differences in milk fat percentage were observed among cows fed the various silages, although there was a trend (P=0.10) toward increased milk fat content with CSH supplementation. Milk protein percentage also tended (P<0.10) to be greater for cows fed CS than for cows fed other forages, which might have been due to the solubility of protein in the diets, as PUN values were greater for cows fed CS diets than for those fed other diets. Cows on BAL treatments had low PUN values compared with cows on other treatments. There was a forage × CSH interaction for PUN because these values were less for the CS without CSH and the reverse for BAL and VAL diets. All cows gained modest amounts of BW during the trial. Cows fed alfalfa diets without CSH gained the least BW.

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TABLE 6. Intake, milk yield, milk composition, and BW changes for cows fed dietsa with different forage sources supplementd with or without cottonseed hulls (CSH). + CSH Item Intake DM, kg/d Energy, Mcal/d Protein, kg/d Milk yield, kg/d Milk composition Fat, % CP, % Feed efficiency Milk, DM BW changes, kg/d PUN,c mg/dL

Contrastb

– CSH

CS

BAL

VAL

RS

CS

BAL

VAL

RS

SEM

F

C

F x C ALF

15.3 26.9 2.78 17.8

19.5 33.7 3.61 19.2

16.5 26.6 2.85 18.9

11.8 20.1 2.41 17.6

15.8 27.3 2.75 21.7

16.5 28.2 3.23 17.3

14.9 23.8 2.84 18.2

11.1 18.2 1.95 17.9

0.54

<0.01 0.22

0.64

0.09

0.40

0.04 0.66

0.08

0.82

4.1 3.2

3.8 3.0

3.7 2.9

4.1 3.0

3.6 3.1

3.7 2.9

3.8 3.1

3.8 3.1

0.18 0.09

0.52 0.10 0.09 0.83

0.44 0.25

0.98 0.49

1.11 0.43 16.4

0.94 0.47 9.1

1.16 0.30 13.6

1.48 0.24 12.5

0.36 0.62 14.1

1.00 0.17 10.6

1.25 0.14 16.1

1.62 0.37 12.5

0.31 0.90

0.14 0.74 <0.01 0.53

0.21 0.54 0.06 <0.01

aCS

= Corn silage, BAL = alfalfa ensiled with Ag-Bag® (Ag-Bag International, Warrenton, OR) system, VAL = alfalfa ensiled with vacuum system, and RS = ryegrass ensiled with Ag-Bag® system. bContrasts: F = forage source, C = CSH vs no CSH, F x C = forage x CSH interaction, and ALF = bagged alfalfa vs vacuumed alfalfa. cPlasma urea nitrogen.

Implications

Acknowledgments

Ensiling crops with a vacuum bag system is an effective method of preserving forages and provides a feasible ensiling option, especially when silage equipment or structures are limited or during emergency conditions. Other beneficial factors include 1) allowing the harvest of a small quantity of forage at optimum quality and 2) enabling small producers to match silo capacities with herd size. Data on extended periods of ensiling are not available, but secondary fermentation could affect silage quality, especially if care is not taken in sealing. Initial costs for this system are minimal, and storage costs are less than ensiling in concrete bunker silos or bagging silage. As with any system, production will depend on forage quality at ensiling and proper care in feed out. Use of CSH may extend the forage supplies and enhance production, but results may not be consistent with different crops or seasons.

The assistance provided by James Bannon, Bobby Smith, and the staff at the E.V. Smith Research Center and the assistance of Kenny Payne of the Canebrake Farms is appreciated. Appreciation is expressed for partially funding of the work through a Producer Grant from the USDA Southern Region Sustainable Agriculture Research and Education (SARE) program.

Literature Cited 1. Achacoso, A. S., D. P. Coleman, and L. L. Rusoff. 1979. Ensiling high dry matter corn. J. Dairy Sci. 62(Suppl. 1): 182 (Abs.). 2. Cromwell, R. P., J. W. Prevatt, and W. J. Becker. 1992. Silo construction and management. In Large Dairy Herd Management. H. H. Van Horn and C. J. Wilcox (Ed). p 619. Am. Dairy Sci. Assoc., Champaign, IL.

3. Forster, L. A., Jr., and M. C. Calhoun. 1995. Nutrient values for cottonseed products deserve new look. Feedstuffs 67(44):16. 4. Gu, S. C. 1998. Effects of supplementation of undegradable intake protein on production performance and digestibility of lactation cows fed different forages. Ph.D. Dissertation, Auburn University, Auburn, AL. 5. Gu, S. C., and B. R. Moss. 1996. Lactation performance of cows fed low and high rumen undegradable protein diets with varying levels of cottonseed hulls and protein. J. Dairy Sci. 79(Suppl. 1): 152 (Abs.). 6. Guyer, P. Q. 1978. Making quality corn and sorghum silage. Great Plains Beef Cattle Handbook. GPE-2400. University of Nebraska, Lincoln, NE. 7. Harris, B., H. H. Van Horn, K. E. Manookian, S. P. Marshall, M. J. Taylor, and C. J. Wilcox. 1983. Sugarcane silage, sodium hydroxide- and steam pressure-treated sugarcane bagasse, corn silage, cottonseed hulls, sodium bicarbonate, and Aspergillis oryzae product in complete rations for lactating cows. J. Dairy Sci. 66:1474. 8. Kung, L., and R. Shaver. 2001. How good is your silage making? Hoard’s Dairyman 146(16): 597. 9. McCartney, D., and L. McCartney. 1999. Utilizing alternative harvesting methods in storing silage. North Central Region SARE Report. University of Nebraska, Lincoln, NE.

Ensiling with a Vacuum System

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