The objectives of this study were to determine the effect of treating corn forage with a microbial silage inoculant (Lactobacillus acidophilus fermentation product). Response to inoculation was compared with untreated forage in terms of chemical fermentation characteristics, preservation of dry matter and digestibility by beed steers

Drake, R.

Kamstra, L. D.

Luther, R. M.

English

Public Research Access Institutional Repository and Information Exchange

South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeSouth Dakota Cattle Feeders Field Day Proceedingsand Research Reports, 1981 Animal Science Reports1981Effect of a Bacterial Silage Inoculant on Quality,Preservation and Utilization of Corn Silage by BeefSteersR. DrakeSouth Dakota State UniversityR. M. LutherL. D. KamstraFollow this and additional works at: http://openprairie.sdstate.edu/sd_cattlefeed_1981This Report is brought to you for free and open access by the Animal Science Reports at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in South Dakota Cattle Feeders Field Day Proceedings and Research Reports,1981 by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For moreinformation, please contact michael.biondo@sdstate.edu.Recommended CitationDrake, R.; Luther, R. M.; and Kamstra, L. D., "Effect of a Bacterial Silage Inoculant on Quality, Preservation and Utilization of CornSilage by Beef Steers" (1981). South Dakota Cattle Feeders Field Day Proceedings and Research Reports, 1981. Paper 4.http://openprairie.sdstate.edu/sd_cattlefeed_1981/41ij1 1111 � r 1lilililil CATTLE FEEDERS DAY E FFEC T  O F  A BACTE RIAL SILA GE INOCULANT ON QUALI T Y, P RE SE RVATI ON AN D UT I L I ZATI ON O F  C O RN SI LA GE B Y  BEE F STEE RS R. Dra ke , R. M .  Luther and L .  D. Kams tra Depa rtment o f  Anima l Sc ienc e Report CATTLE Bl-3 Summary Corn forage harvested from the 1 9 79 corn crop was ensiled in two experi­mental concrete silos .  Moisture content. of the forage was 62% .  One silo (untreated) was filled with 3680 lb . of forage and the other was filled with 3628 lb . of forage inoculated with a Lactobacillus acidophilus fermentation product applied at a rate of 1 lb . per ton of wet forage . Silage fermenta­tion was monitored by collecting samples through sampling ports  in the silos over a 2 7-day period . Heat of fermentation was determined by temperature probes within the silos . Temperatures were higher in untreated than in treated silage during the fermentation period . Peak temperature (9 1  F) for treated silage was recorded 2 to 3 days earlier than untreated silage which peaked at 95 F. Chemical profiles were obtained on samples collected at enBiling , during fermentation and as the silage was removed for feeding . Lactic acid formation was generally higher for treated than for untreated silage throughout the fermentation p eriod . Highes t  concentrations of lactic acid were observed in untreated silage 4 days later than in treated s ilage . Organic acid (acetic and prop ionic ) concentrations were also higher in treated silage . Butyric acid was detected at very low concentrations in either silage . Ammonia nitrogen levels were lower in treated silage . Differences in chemical profiles between untreated and treated silage were less evident as the silage was removed from the silo for feeding. Lactic and total volatile fatty acids were only slightly higher in the treated silage.  Recovery of  dry mat ter was 82 . 9% for untreated silage and 84 . 2% for treated silage . Digestibility of dry matter , crude protein and organic matter by beef s teers was similar for the two silages. Nitrogen retention was only slightly lower for the treated silage . Results of these studies show that treatment of corn forage with a microbial silage inoculant improved the fermentative characteristics of the silag e .  Benefits o f  lower heat production and increased organic acid concen­tration observed throughout the fermentation did not appear to carry through to the silage as it was removed and fed to beef steers . Problems of moisture entering the silos appear to be related to the disparity in fermentation characteristics and the quality of s ilage removed from the silo . Introduction The making of quality silage is largely dependent upon the fermentation process  that takes p lace in the forage after ens iling . It is generally believed that the number and type of microorganisms present in the ensiled forage is sufficient to init iate fermentation, especially in corn forage , a favorable material for ensiling . However , research has shown that microbial numbers can vary widely even in corn forage .  Low microbial populations app ear to s low the rate and extent of fermentation. The conditions which 7 - 2 -contribute to low microbial numbers are not known . Inoculation of forage with desirable bacteria offers a means of providing additional bacteria to initiate rap id fermentation and to allow it to proceed at a faster rate with reduced heat production. The expected result would be to improve preserva­tion of nutrients and produce higher quality silage. The obj ectives of this study were to determine the ef fect of treating corn forage with a mfcrobial s ilage inoculant (Lactobacillus acidophilus fermentation product • Response to inoculation was compared with untreated forage in terms of chemical fermentation characteristics , preservation of dry matter and digestibility by beef st eers. Procedures Corn forage from the 197 9  corn crop was harvested with a conventional forage chopper. The yield of corn grain was 108 bushels per acre (�5% moisture) .  The chopped forage was weighed into a feed mixing wagon equipped with a scale and allowed to mix for about 10 minutes. The forage was trans­ferred to two concrete experimental silos used for silage prep aration .  One silo was filled with untreated forage . The other silo was filled with forage inoculated with Lactobacillus acidophilus at a rate of 1 lb. of product per ton of wet forage. The silo structures were reinforced concrete culverts 6 feet high , 5 feet inside diameter with a 4-inch wall . Each silo was equipped with a 14-inch door opening the height of the silo and six sampling ports . The sampling ports were 1 and 1 1/2 inches in diameter , situated in the silo wall 3 feet 0 above the bottom and spaced at 60 angles. The silos were placed on a concrete s lab equipped with a ''U'' shaped trough for collection of seepage liquids. Packing was accomplished by two persons walking on the surface of the silage during filling. The silos were covered with a plastic cover and a wooden lid placed on the plastic such that the lid fit inside the silo .  Cement blocks were placed on the lid to provide 1200 lb. weight . An indoor-outdoor thermometer was installed through one sampling port  with a sensor located in the center of the silo. Temperatures of the silage were recorded at noon and at 5 p.m .  daily for about 1 month after ensiling . Samples were collected during ensiling , twice weekly through the ports during the fermentation period of 27 days and as the silage was removed from the silo. The material was placed in double p lastic bags , closed with a fastener and immediately frozen for later chemical analysis. A chemical silage quality profile was completed in the laboratory on all samples. Moisture was determined by drying a 100-gram quantity in a forced air oven at 70 C for 24 hours and also by a toluene distillation method . Other characteristics of the profile determined were pH,  titratable acidity , total nitrogen , ammonia nitrogen , organic acids ( acetic , propionic ,  butyric) , lactic acid and inorganic ash. 1 2 Sila-Bac Silage Inoculant , Pioneer Hi-Bred International. Blair Manufacturing Company, Blair , Nebraska. 8 - 3 -Preservation of nutrients was determined on the basis of dry matter ens iled and removed from the s ilo. Spoiled silage was sep arated from the good silage , weighed and sampled as the silos were being emp tied . Utilization of nutrients from untreated and treated silage was deter­mined in a digestion-nitrogen balance trial with beef s teer s . Twelve steers averaging 628 lb . were p laced in individual pens at the Animal Science Complex. The pens were equipped with automatic waterers and were situated over a concrete slatted floor.  The steers were fed corn s ilage produced locally for about 2 weeks . The steers were then weighed and allotted to the two silage treatments with six steers per treatment . The experimental silages were full­fed for an additional week and the steers were p laced in metabolism crate s .  A supplement consisting o f  soybean meal,  9 1 . 18% ;  dicalcium phosphate , 6 . 08% and trace mineral salt , 2 . 73% was fed to each steer at a rate of 1 . 65 lb . per day . Vitamin A was added to the supplement to provide 15 , 700 I . U .  of vitamin A daily . The steers were allowed to adj ust to the metabolism crates and a 5-day total collection digestion-nitrogen balance trial was conducted . The steers were fed silage twice daily and refusals were weighed the following morning . Urine and feces were collected once daily , measured or weighed and a 10% aliquot saved for chemical analysis . The fecal material was dried in a forced air oven at 70 C for 36 hours . Measures of utilization included digestible dry matter , crude protein, organic matter and nitrogen retention .  Results Silage Fermentation Characteristics Heat production for untreated and treated s ilage is indicated by the temperature curves presented in figure 1 .  The temperatures of the forage following ensiling were 68 F and increased rapidly the first week after ens iling . The highest temperatures observed for untreated and treated silage were 95 and 9 1  F ,  respectively , with the treated silage reaching a peak 2 to 3 days earlier than untreated silage. Temperatures were higher in untreated silage than in treated s ilage throughout the fermentation period . Lactic acid formation was greater in treated silage than in untreated s ilage as shown in f igure 2 .  Concentrations o f  the acid increased rapidly early in the fermentation of treated silage. In the untreated silage , lactic acid formation appeared to be slowed for about 6 days after ensiling but then increased rap idly to 10 day s .  Peak lactic acid production was obs erved at 13 days following ens iling with the treated s ilage and at 1 7  days with the untreated s ilage.  Formation of lactic acid tended to decline thereafter in both silages . Variation in acid formation during the fermentation period appeared to be caused by collecting the fermented samples from sampling ports located at different positions in the silo .  Formation of total volatile fatty acids was higher in inoculated s ilage than in untreated silage as shown in f igure 3 .  Acetic acid , a maj or component .of volatile fatty acids in s ilage, accounted for 2 . 95 %  of the dry matter in treated silage when acid production was at its peak. This compares with 4 . 1 3% in untreated silage at peak acid production (14 days after ensiling ) . Propionic acid comprised a smaller proportion of the fatty acids and was generally higher in treated than in untreated silag e .  Butyric acid , an indicator of improper fermentation, was present at very low concentrations in either silage. 9 - 4 -100 Untreated Silage J 90 � bl) i:: •i-1 ""Cl tO Q) p::; i:: 80 0 / 0 z Treated Silage � 0 .. Q) 70 ,.. ::l 1-J tO ,.. Q) p. a Q) E-< 50 0 5 10 15 20 25 30 Days After Ensiling Figare 1. Fermentation Temperatures for Untreated and Treated Corn Silage . 10 6 5 i... <U µ µ 4 Cll � :;:.., i... i:::l � 0 µ i:: 3 (]J (.) i... <Il p... .. 'tl •r-1 (.) < (.) 2 •r-1 µ (.) Cll ....:i 1 - 5 -Treated Silage II/ ..,... 0 5 10  15  20 25 Days After Ensiling Figure 2 .  Lactic Acid in Untreated and Treated Corn Silage. 1 1  30 � 4 .. � 3 •.-l � :>. .µ .µ ti! ""' � 2 •.-l .µ ti! i-1 g - 6 -Treated s·1 1 age 25 30 12 - 7 -Measurements of  titratable acidity coincided with organic acid production. Differences in pH were small and tended to parallel titratable acidity and organic acid concentrations . There appeared to be no appreciable reduction in crude protein content in either of the silages during the fermentation period . However , ammonia nitrogen was consistently lower for the treated s ilage , possibly indicating protein destruction in the untreated silage . Silage Quality and Preservation The chemical profiles of corn forage ensiled and those  of silage removed from the silo for feeding are presented in table 1 .  The silo which contained the untreated silage was filled about 2 hours prior to filling of the silo used for treated silage.  The forage from both silos  was harvested as  one load about 3 hours prior to filling the first silo . Therefore , chemical changes in the forage could have occurred in this 5-hour period but were likely to have been minimal .  Results of chemical analyses show the formation of small concentrations of lactic and other organic acids . This would indicate that fermentation had been initiated prior to or during the ensiling process .  There were only small differences , however , between forage p laced in the first s ilo (untreated) and that place in the second silo (microbial treated) . Table 1 .  Chemical Profiles o f  Corn Forage and Silage for Feeding as Affected by Bacterial Inoculationa Ens iled Untreated Dry matter , %b 38 . 81 pH 5 . 79 Titratable acidityc 1 .  35 Percent of dry matter Ash 5 . 04 Crude protein d 7 . 58 Ammonia nitrogen . 26 Lactic acid . 06 Volatile fatty acids Acetic 0-Te Prop ionic 1 . 49 Butyric . 08 Total 1 . 57 Acid-detergent fiber 27 . 12 Acid-detergent lignin 3 . 58 corn forage Treated 38 . 14 5 . 80 1 . 46 5 .  39 7 . 50 .26 . 08 0-T • 7 1  . 04 • 75 26 . 67 3 . 76 Silage for Untreated 36 . 86 4 . 38 6 . 42 4 . 84 8 . 79 . 66 3 . 15 . 95 . 5 7  . 13 1 .65 2 8 . 50 4.2 1  feeding Treated 35 . 1 7  4 . 6 1 8 . 27 5.5 3  8 . 39 . 64 3 . 59 1 . 35 . 68 . 0 1 2 . 04 26 . 47 3 . 73 a Inoculated with Lactobacillus acidophilus fermentation product at rate of � lb . per ton of forage.  To luene distillation. � Milliliters of  . lN KOH to raise pH to 7 .  Percent o f  crude protein. e T = trace .  1 3  - 8 -Silage for feeding was removed from the silo in January of 1980 ,  starting 96  days after ens iling . Titratable acidity , lactic and volatile fatty acids were higher in treated silage than in untreated silag e .  Differ­ences between the two silages,  however , were not as prominent as those observed during the fermentation period . Inoculated silage also had a higher moisture content and somewhat less acid-detergent f-iber than untreated s ilage. Table 2 shows the recovery and losses of dry matter in untreated and treated silage.  The moisture content was slightly higher f or forage that was inoculated with microorganisms , resulting in fewer pounds of total dry matter ensiled f or this treatment . Dry matter recovered as silage f or feeding from the treated silage was 84 . 2% of the dry matter ensiled compared to 82 . 9% for the untreated silage . Spoilage losses and nonrecoverable losses amounted to 1 7 . 0% for untreated silage and 1 5 . 8% for treated silage . Table 2 .  Dry Matter Recovery of Corn Silage as Affected by a Microbial Silage Inoculanta Dry matter of corn f orage,  % Total dry matter ens iled , lb . Total dry matter of feed s ilage , lb . As a percent of dry matter ensiled , % Dry matter losses Spoilag e ,  lb . As a p ercent o f  dry matter ensiled , % Nonrecovered , lb . As a percent of dry matter ensiled , % Untreated 38 . 83 1428 . 6  1 1 84 .  8 82 . 94 145 . 9  1 0 . 2 1  97 . 9  6.85 Treated 38 . 14 1 383 . 7  1 1 64 . 7 84 . 17 1 38 . 6  1 0.02 80 . 4  5 . 81 a Lactobacillus acidophilus fermentation product applied at 1 lb . per ton of forage.  Silage Utilization Results of digestion and nitrogen balance s tudies with beef steers fed the untreated and treated silage are presented in table 3 .  The s ilage used in these studies was the material upon which quality and preservation measurements (tables 1 and 2 )  were obtained . Data from the digestion experi­ment indicate only small differences between the two silage treatment s  with respect to the digestibility of dry matter , crude protein and organic matter . The retention o f  nitrogen (grams/ steer/day) was slightly lower for s teers fed the treated silage as compared to those  fed the untreated silage . ·Retention 14 - 9 -Table 3 .  Digestibility and Nitrogen Retention With Beef Steers Fed Untreated and Microbial Inoculated Corn S ilage Number of steers Average weight , lb . Avg .  daily dry matter intake , lb . Avg . daily nitrogen intake , lb . Digestib ility, ! Dry matter Crude protein Organic matter Nitrogen balance , grams/day Fecal Urinary Retained Percent retained of consumed Untreated 6 628 1 2 . 19  . 26 69 . 45 68 . 06 7 1 . 1 7 37 . 2  43 . 2  35 . 8  30 . 6  Treateda 6 6 2 7  1 2 . 36 . 25 68 . 83 67 . 72  70 . 65 36 . 8  44 . 4  32 . 7  28 . 4  a Inoculated with Lactobacillus acidophilus fermentation product at rate of 1 lb . per ton of forage . of  nitrogen based upon nitrogen consumed amounted to 30 . 6% for steers fed the untreated silage and 2 8 . 4%  for steers fed the treated silage . Discuss ion and Comments The experimental silos used in these studies were useful in monitoring chemical changes  occurring in the silage during fermentation. The quantity of s ilage produced was adequate to evaluate the treatments in a short-term feeding experiment with smaller numbers of beef cattle . Chemical profiles obtained during this study indicated that silage quality was within the range of that observed with silage produced in larger s torage s tructures . A problem was encountered during the experiment with moisture , from rain , penetrating the plastic s ilo cover.  A hard rain was experienced about 30 days after ensiling causing water to move into the silo . An amber-colored liquid filled the seepage containers with substantial overflow.  The volume of  runoff liquid was not measured . However , runoff appeared to be greater for the silo containing the treated s ilage . Analysis of the runoff showed that it contained rather high concentrations of organic acids , indicating the loss of acidity produced during fermentation. This might possibly explain the lower concentrations of lactic and volatile fatty acids observed in the silages used for feeding compared to silages taken at the end of the fermentation period . Los ses of soluble 1 5  - 1 0  -nitrogen and carbohydrates may also have occurred in the runoff . These losses might be expected to narrow the differences between the silages as was shown in the digestion-nitrogen balance study with cattle. Silage quality was improved by microbial inoculation of corn forage as indicated by chemical profiles obtained during and at the end of the fermenta­t ion period . This improvement was not as pronounced when the silage was removed from the silo . Differences in utilization by beef cattle likewise did not parallel chemical changes that favored the silage inoculated with microorganisms . Prepared for Cattle Feeders Day , Brookings ,  South Dakota, January 14 , 1 9 8 1 . 1 6  

Effect of a Bacterial Silage Inoculant on Quality, Preservation and Utilization of Corn Silage by Beef Steers

https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1003&amp;context=sd_cattlefeed_1981

Effect of a Bacterial Silage Inoculant on Quality, Preservation and Utilization of Corn Silage by Beef Steers

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