E N S I L E D B R O I L E R L I T T E R AND C O R N F O R A G E . I. F E R M E N T A T I O N C H A R A C T E R I S T I C S x ,2 B. W. Harmon a, J. P. Fontenot and K. E. Webb, Jr. Virginia Poltechnic Institute and State University 4, Blacksburg 24061 Summary The objectives of the research were to study fermentation characteristics and microbial concentration of ensiled mixtures of different ratios of broiler litter and corn forage harvested at two stages of maturity. Corn forage harvested at each stage of maturity was ensiled with broiler litter supplying 15, 30 and 45% of the total dry matter of ensiled mixtures. Untreated forage and forage containing ~.5% urea, wet basis, were also ensiled. Mixtures were ensiled in small polyethylene bags containing 2 kg of initial material or in large bags containing 114 kg of initial material. Samples representing litter, initial forage, initial mixtures and silages were analyzed for various components. Plate counts for total bacteria and coliforms were conducted on the small-bag silages. All mixtures preserved well and appeared to show typical fermentation characteristics. Percent dry matter in silage was significantly increased by advancing maturity of corn forage and by each level of litter addition. Addition of litter significantly increased the crude protein content of the silage. For example, the crude protein contents of the small bag silages containing corn forage cut at maturity 2 (36% dry matter) were 7.8% for the control silage, compared to 10.5, 12.3 and 16.9% for the silages containing 15, 30 and 40% broiler litter, dry basis, respectively. The addition of urea or litter to corn forage at ensiling time resulted in silages with higher final pH values and greater
concentrations of lactic and acetic acids than control silage. Total bacteria counts of the silages were in excess of 3 million bacteria per gram. However, only the silage containing 45% litter dry matter, maturity 1, and 30 and 45%, maturity 2 had significantly more bacteria than the control silages. The coliform population was generally lower for the silages containing fitter than for the control sllages.
Introduction
Broiler litter, an accumulation of poultry excreta, feathers, wasted feed and bedding, is valuable as a feed for ruminants (Noland et al., 1955; Southwell et aL 1958; Fontenot et al., 1966, 1971). The chemical composition of litter, especially the high nitrogen content, suggests that feeding to ruminants would be an excellent way to convert nutrients in the waste into meat for human consumption. Studies by Bhattacharya and Fontenot (1965) indicated that the nitrogen was efficiently utilized by sheep when up to 50% of the dietary nitrogen was supplied by litter. Acceptable feedlot performance was obtained when cattle were finished on rations containing up to 25% fitter but performance was markedly depressed when rations contained 50% litter (Fontenot et aL 1971). The lowered performance of the cattle consuming high-litter rations appeared to be a result of low feed intake. The practice of recycling broiler litter by aSupported in part by Public Health ServiceGrant feeding is not sanctioned by the Food and Drug No. EC-00034. 2The broiler fitter was supplied by Rockin~gham Administration (Kirk, 1967; Taylor, 1971). Poultry MarketingCooperative,Broadway,Virgima~ Although no serious health problems have Sl'resent address: Department of Agriculture, resulted from feeding broiler fitter, there is University of Maryland, Eastern Shore, Princess Anne apprehension concerning the dangers of path21853. 4Department of AnimalScience. ogenic organisms in litter fed to livestock. 144 JOURNAL OF ANIMAL SCIENCE Vol. 40, No. 1, 1975
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ENSILED BROILER LITTER AND CORN FORAGE Fontenot et al. (1971) reported that dry heat effective in destroying bacteria present in broiler litter. Perhaps a natural means of destroying microorganisms, such as ensiling litter with high-grain corn forage, would be more economical and convenient than the use of artificial heat. The ensiling process is characterized by the production of heat and organic acids, namely acetic and lactic, followed by quiescence during which the lactic acid concentration remains stable and the pH of the fermenting mass becomes constant atabout 4 (Barnett, 1954). Ensiling broiler litter might offer other advantages, such as improved nutrient composition of the corn silage, improved palatability of the waste and convenient use of silage feeding equipment. The overall objective of the study reported herein was to study the feasibility of ensiling broiler litter and corn forage. This paper reports the fermentation characteristics and microbial population studies of mixtures of different ratios of broiler litter and corn forage cut at two stages of maturity. was
Experimental Procedures Wood shaving broiler litter, collected from a commercial broiler house, was used in this study. One group of broilers had been produced on the litter. The material was screened through an expanded metal grid (2 cm) to remove caked material and was mixed prior to blending with corn forage. Corn forage was harvested from the same plot at two stages of maturity (30 and 40% dry matter by field sampling). At maturity 1 (30% DM) the grain was in the soft dough stage, and the husks and bottom leaves were beginning to brown. At maturity 2 (40% DM) the grain was in the hard dent stage, and husks and leaves below the ear were brown. Sma//-bag S//ages, At each harvest, the forage was mixed with the following: control, untreated; urea, .5% wet basis; and levels of litter to supply 15, 30 and 45% of the total dry matter (designated as litter-15, litter-30 and litter-45). The mixing and initial sampling were conducted according to the following procedure: 1) For each treatment, approximately 25 kg of forage were removed from the silage wagon and spread on a concrete floor for mixing; 2) An initial forage sample was taken b y compositing small amounts from the entire mass; 3) A total of eight 2-kg mixtures (two for initial mixture samples and six for ensiling) were individually prepared by weighing the desired amounts of forage and additive, and
145
mixing by hand; 4) The six replicates to be ensiled were firmly packed into polyethylene bags supported by cardboard food containers; 5) The samples of initial forage and initial mixture were placed in polyethylene bags and frozen until analyzed. The mixtures were allowed to ferment for a minimum of 61 days. The small-bag silages were weighed and opened after fermentation for an average of 67 days for maturity 1 and 63 days for maturity 2 (range of 61 to 72 days for maturity 1 and 61 to 68 days for maturity 2 for the six replicates). At the time the bags were opened, samples were removed for microbial counts and the bags were resealed and frozen for later analysis. Large-Bag Silage& In conjunction with preparing the small-bag silages for fermentation and microbial counts, large-bag silages were also prepared for fermentation and sheep-feeding studies. Treatments for the large-bag study were: control; .5% urea, wet basis;,and levels of litter to supply 15 and 30% of the total dry matter (designated as litter-15 and litter-30). The large-bag silages were prepared in 228 to 570 kg batches and packed firmly into doubled .004 nun polyethylene bags containing 114 kg material per bag. The forage for a particular batch of silage was weighed and spread on a concrete floor. The additive was weighed and sprinkled over the entire mass of forage and the material was thoroughly mixed by turning with shovels. Samples, taken to represent each initial forage and each initial mixture, were placed in polyethylene bags and frozen for later analysis. At each harvest, an amount equivalent to about 454 kg of dry matter for each of the four treatments was prepared. The bags were stored in an unheated barn from harvest (September 7 and October 1 for 30 and 40% dry matter corn forage, respectively) until January 16, at which time the feeding studies began. During each of the 55 days that silage was fed, 100 g samples of each silage were taken at each feeding. Samples were individually frozen and later composited by 5-day periods to give 11 samples of each silage for analysis. Chemical and Microbial Analyses. Total and ammonia nitrogen were determined on wet initial forages, initial mixtures, silages and air dry litter by A.O.A.C. (1970) methods. The factor of 6.25 was used to convert nitrogen to crude protein. Dry matter of forages, mixtures and silages was determined by drying two 200 g samples in 85 C forced air for 48 hours. After air equilibration, the two dried samples were ground to pass a 1 mm seive, composited and subjected to proximate analysis. All air dry
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146
HARMON, FONTENOT AND WEBB, JR. TABLE 1. CHEMICAL COMPOSITION OF BROILER LITTER AND FORAGES AT HARVEST
Item
Dry matter, % Composition of dry matter, % Crude protein
Small-bag forageb Large-bag foragee Littera Maturity 1 Maturity 2 Maturity 1 Maturity 2 82.92
25.22d
37.68 e
25.85 d
38.14 e
Ether extract Crude fiber
26.75 1.53 28.00
8,35 d 2.49 24.08 d
7.28 e 2.34 21.11e
8.23 d 1.90 d 24.65d
7.41 e 1.71e 22.52e
NFE
32.04
60,87 d
65.76 e
61.27d
64.88e
Ash
16.71
4.21d
3.50e
3.95d
3.48e
4.40 .98
32.38d .04d
23.36e .03 e
31.56d .04d
23.41e .03e
22.90
3.23 d
2.42 e
3.36d
2.73e
Water-soluble carbohydrates Ammonia nitrogen Ammonia nitrogen, % of total nitrogen
"Values represent the average of 10 samples taken at the t/me of mixing with corn forage. bValues represent an average of five samples of forage for each matmdty. CValues represent an average of 16 samples of forage for each matu~ty. d,ewithln small-bag forage or large-bag forage, means for same vaziables having different supersct4pta were M_mniflCantly different (P < .05).
samples were analyzed for crude fiber (Whitehouse et al., 1945), dry matter, ether extract, ash and NFE (A.O.A.C., 1970). A water extract of the forage, mixture and silage samples was prepared by homogenizing 25 g wet material with 100 nd water in a blender at full speed for 2 minutes. The contents were filtered through four layers of cheesecloth and the filtrate was subjected to measurements of pH (electrometricaUy), volatile fatty acids (Erwin et at, 1961), lactic acid (Barker and Summerson, 1941, as modified by Pennington and Sutherland, 1956) and watersoluble carbohydrate content (Dubois et al, 1956, as adapted to corn plants by Johnson et at, 1966a). All chemical analyses were conducted in duplicate. Counts f?r total bacteria and coliforms were determined on aseptically prepared water extracts plated and cultured according to the standard method for testing pasteurized milk (Anonymous, 1967). A range of dilutions was plated and all within the limits of the Quebec Colony Counters (up to 300 colonies per plate) were counted. Statistical Treatment All data were analyzed by least squares analysis o f variance (Ostle, 1963). The multiple range test of Duncan (1955) was used to test for significant differences among means. s American Optical Corp., Buffalo, N.Y.
Results and Discussion Composition of Broiler Litter and Initial Forage. The chemical composition of the broiler litter used in these studies is presented in table 1. Dry matter content of the l0 samples averaged 82.92%. The crude protein content of 26.75%, dry basis, was somewhat lower than litter used previously in this laboratory (Bhattacharya and Fontenot, 1965, 1966; Fontenot et aL, 1971). A factor probably contributing to the low crude protein content was the high crude fiber value of 23%, indicating that the litter contained a considerably higher proportion of the original base material than in previous studies, thus diluting the accumulation of excreta, feathers and wasted feed. Ammonia nitrogen, .98% of dry matter and 22.90% of total nitrogen, was similar to values reported by Caswell (1972) for unprocessed fitter. Bhattacharya and Fontenot (1965) reported that ammonia nitrogen contributed 13% of the total nitrogen of litter containing 5.1% nitrogen, dry basis. The composition of initial corn forage harvested at two maturities is also presented in table 1. The forage contained 25.22% DM for maturity 1 and 37.68% DM for maturity 2 for the small-bag study. Corn harvested at maturity 1 had significantly more crude protein, crude fiber, ash and water-soluble carbohydrates and less NFE than at maturity 2. Forage contained 32.38% and 23.36% water-soluble carbohy-
Downloaded from https://academic.oup.com/jas/article-abstract/40/1/144/4668045 by University of Wyoming Libraries user on 19 June 2018
ENSILED BROILER LITTER AND CORN FORAGE
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148
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drates at maturities 1 and 2, respectively. These values show a similar response to maturity as those reported by Johnson et aL (1966a) who observed that whole corn plants containing 25 to 30% DM contained about 30% soluble carbohydrate, and corn plants of 40% Dirt had 25% soluble carbohydrate, dry basis. The crude protein content of corn forage decreased from 8.25% for maturity 1 to 7.28% for maturity 2. Johnson et al (1966b) also observed decreased crude protein of corn forage with maturity after corn plants reached about 30% DM. The decrease in crude fiber and increase in NFE with respect to maturity can be explained by the fact that as the corn plant matures the grain contributes proportionately more of the total dry matter of the plant (Johnson et aL, 1966b). The composition of initial forage for the large-bag study shows similar values as for the small-bag study. Differences between maturities were significant for all components measured. _ Composition of Initial Mixture~ The chem9 ical composition of the initial mixtures of corn v forage and corn forage plus urea or litter for the ~, small-bag study is presented in table 2 and for ~ the large-bag study, in table 3. Values for the i small-bag study (table 2) represent the average r~ of two replicate samples per silage. Dry matter content of small-bag mixtures was significantly increased by advancing corn !~ forage maturity and by each level of broiler litter addition. Percentages of crude protein and ash were also significantly affected by maturity and level of litter addition. A significant depression in water-soluble carbohydrate was noted for advancing maturity of the corn plant and for each level of litter addition. Johnson et (1966a) observed a reduction in watersoluble carbohydrate with advancing corn plant maturity. The depression ~ssociated with litter addition was expected since the litter contained only about 4.4% water soluble carbohydrate, dry basis. I The composition of initial mixtures for the large-bag study is presented in table 3, the values representing the average of eight samples per silage. Generally, the values for a particular ~ mixture corresponded closely with values of the i corresponding small-bag mixture. Composition and Fermentation Characteris~ticsofSilage~Thecompositionofensiledcorn forage and mixtures of corn forage plus urea or ~ broiler litter is presented in tables 4 and 5 for the small-bag and large-bag studies, respectively. [~ The values in table 4 for the small-bag study represent the average of six replicate samples of -z each silage. Dry matter was significantly increased by advancing maturity of the corn
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ENSILED BROILER LITTER AND CORN FORAGE
151
T A B L E 6. T O T A L AND AMMONIA N I T R O G E N OF INITIAL AND F E R M E N T E D M A T E R I A L , SMALL-BAG STUDY
Silage
Total nitrogen, % of DM
Ammonia nitrogen, % of total nitrogen !
Maturity
Treatment
1 1 1 1 1
Control Urea Litter Litter-30 Litter-45
2 2 2 2 2"
Control Urea Litter-15 Litter-30 Litter-45
Initiala
Fermenteda
Initial
Fermentedb
1.32d 2.14 h 1.98g 2.42i 2.94k
1.42d 2.33h 1.99g 2.52i 3.01k
2.82c 5.17d 11.08 e 14.48g 17.04h
5.34e 8.09 d 12.04 e 16.49 f 19.88h
1.24c 1.78 f 1.68 e 1.97g 2.70]
1.21e 1.84 f 1.70e 2.31h 2.80 J
2.55 e 10.31 e 10.04e 12.44f 16.02h
5.08e 12.17 9 12.19e 16.48f 17.75g
aWhen statistically analyzed over b o t h stages of matuzity, values were al_m~ifleantlu affected (P < .01) b y maturity. b W h e n statiz~cally analyzed over b o t h stages of m a t t ~ t y , values were s/gniflcantly affected (P
concentrations of lactic and acetic acids than control silage. Total bacteria counts of the silages were in excess of 3 million bacteria per gram. However, only the silage containing 45% litter dry matter, maturity 1, and 30 and 45%, maturity 2 had significantly more bacteria than the control silages. The coliform population was generally lower for the silages containing fitter than for the control sllages.
Introduction
Broiler litter, an accumulation of poultry excreta, feathers, wasted feed and bedding, is valuable as a feed for ruminants (Noland et al., 1955; Southwell et aL 1958; Fontenot et al., 1966, 1971). The chemical composition of litter, especially the high nitrogen content, suggests that feeding to ruminants would be an excellent way to convert nutrients in the waste into meat for human consumption. Studies by Bhattacharya and Fontenot (1965) indicated that the nitrogen was efficiently utilized by sheep when up to 50% of the dietary nitrogen was supplied by litter. Acceptable feedlot performance was obtained when cattle were finished on rations containing up to 25% fitter but performance was markedly depressed when rations contained 50% litter (Fontenot et aL 1971). The lowered performance of the cattle consuming high-litter rations appeared to be a result of low feed intake. The practice of recycling broiler litter by aSupported in part by Public Health ServiceGrant feeding is not sanctioned by the Food and Drug No. EC-00034. 2The broiler fitter was supplied by Rockin~gham Administration (Kirk, 1967; Taylor, 1971). Poultry MarketingCooperative,Broadway,Virgima~ Although no serious health problems have Sl'resent address: Department of Agriculture, resulted from feeding broiler fitter, there is University of Maryland, Eastern Shore, Princess Anne apprehension concerning the dangers of path21853. 4Department of AnimalScience. ogenic organisms in litter fed to livestock. 144 JOURNAL OF ANIMAL SCIENCE Vol. 40, No. 1, 1975
Downloaded from https://academic.oup.com/jas/article-abstract/40/1/144/4668045 by University of Wyoming Libraries user on 19 June 2018
ENSILED BROILER LITTER AND CORN FORAGE Fontenot et al. (1971) reported that dry heat effective in destroying bacteria present in broiler litter. Perhaps a natural means of destroying microorganisms, such as ensiling litter with high-grain corn forage, would be more economical and convenient than the use of artificial heat. The ensiling process is characterized by the production of heat and organic acids, namely acetic and lactic, followed by quiescence during which the lactic acid concentration remains stable and the pH of the fermenting mass becomes constant atabout 4 (Barnett, 1954). Ensiling broiler litter might offer other advantages, such as improved nutrient composition of the corn silage, improved palatability of the waste and convenient use of silage feeding equipment. The overall objective of the study reported herein was to study the feasibility of ensiling broiler litter and corn forage. This paper reports the fermentation characteristics and microbial population studies of mixtures of different ratios of broiler litter and corn forage cut at two stages of maturity. was
Experimental Procedures Wood shaving broiler litter, collected from a commercial broiler house, was used in this study. One group of broilers had been produced on the litter. The material was screened through an expanded metal grid (2 cm) to remove caked material and was mixed prior to blending with corn forage. Corn forage was harvested from the same plot at two stages of maturity (30 and 40% dry matter by field sampling). At maturity 1 (30% DM) the grain was in the soft dough stage, and the husks and bottom leaves were beginning to brown. At maturity 2 (40% DM) the grain was in the hard dent stage, and husks and leaves below the ear were brown. Sma//-bag S//ages, At each harvest, the forage was mixed with the following: control, untreated; urea, .5% wet basis; and levels of litter to supply 15, 30 and 45% of the total dry matter (designated as litter-15, litter-30 and litter-45). The mixing and initial sampling were conducted according to the following procedure: 1) For each treatment, approximately 25 kg of forage were removed from the silage wagon and spread on a concrete floor for mixing; 2) An initial forage sample was taken b y compositing small amounts from the entire mass; 3) A total of eight 2-kg mixtures (two for initial mixture samples and six for ensiling) were individually prepared by weighing the desired amounts of forage and additive, and
145
mixing by hand; 4) The six replicates to be ensiled were firmly packed into polyethylene bags supported by cardboard food containers; 5) The samples of initial forage and initial mixture were placed in polyethylene bags and frozen until analyzed. The mixtures were allowed to ferment for a minimum of 61 days. The small-bag silages were weighed and opened after fermentation for an average of 67 days for maturity 1 and 63 days for maturity 2 (range of 61 to 72 days for maturity 1 and 61 to 68 days for maturity 2 for the six replicates). At the time the bags were opened, samples were removed for microbial counts and the bags were resealed and frozen for later analysis. Large-Bag Silage& In conjunction with preparing the small-bag silages for fermentation and microbial counts, large-bag silages were also prepared for fermentation and sheep-feeding studies. Treatments for the large-bag study were: control; .5% urea, wet basis;,and levels of litter to supply 15 and 30% of the total dry matter (designated as litter-15 and litter-30). The large-bag silages were prepared in 228 to 570 kg batches and packed firmly into doubled .004 nun polyethylene bags containing 114 kg material per bag. The forage for a particular batch of silage was weighed and spread on a concrete floor. The additive was weighed and sprinkled over the entire mass of forage and the material was thoroughly mixed by turning with shovels. Samples, taken to represent each initial forage and each initial mixture, were placed in polyethylene bags and frozen for later analysis. At each harvest, an amount equivalent to about 454 kg of dry matter for each of the four treatments was prepared. The bags were stored in an unheated barn from harvest (September 7 and October 1 for 30 and 40% dry matter corn forage, respectively) until January 16, at which time the feeding studies began. During each of the 55 days that silage was fed, 100 g samples of each silage were taken at each feeding. Samples were individually frozen and later composited by 5-day periods to give 11 samples of each silage for analysis. Chemical and Microbial Analyses. Total and ammonia nitrogen were determined on wet initial forages, initial mixtures, silages and air dry litter by A.O.A.C. (1970) methods. The factor of 6.25 was used to convert nitrogen to crude protein. Dry matter of forages, mixtures and silages was determined by drying two 200 g samples in 85 C forced air for 48 hours. After air equilibration, the two dried samples were ground to pass a 1 mm seive, composited and subjected to proximate analysis. All air dry
Downloaded from https://academic.oup.com/jas/article-abstract/40/1/144/4668045 by University of Wyoming Libraries user on 19 June 2018
146
HARMON, FONTENOT AND WEBB, JR. TABLE 1. CHEMICAL COMPOSITION OF BROILER LITTER AND FORAGES AT HARVEST
Item
Dry matter, % Composition of dry matter, % Crude protein
Small-bag forageb Large-bag foragee Littera Maturity 1 Maturity 2 Maturity 1 Maturity 2 82.92
25.22d
37.68 e
25.85 d
38.14 e
Ether extract Crude fiber
26.75 1.53 28.00
8,35 d 2.49 24.08 d
7.28 e 2.34 21.11e
8.23 d 1.90 d 24.65d
7.41 e 1.71e 22.52e
NFE
32.04
60,87 d
65.76 e
61.27d
64.88e
Ash
16.71
4.21d
3.50e
3.95d
3.48e
4.40 .98
32.38d .04d
23.36e .03 e
31.56d .04d
23.41e .03e
22.90
3.23 d
2.42 e
3.36d
2.73e
Water-soluble carbohydrates Ammonia nitrogen Ammonia nitrogen, % of total nitrogen
"Values represent the average of 10 samples taken at the t/me of mixing with corn forage. bValues represent an average of five samples of forage for each matmdty. CValues represent an average of 16 samples of forage for each matu~ty. d,ewithln small-bag forage or large-bag forage, means for same vaziables having different supersct4pta were M_mniflCantly different (P < .05).
samples were analyzed for crude fiber (Whitehouse et al., 1945), dry matter, ether extract, ash and NFE (A.O.A.C., 1970). A water extract of the forage, mixture and silage samples was prepared by homogenizing 25 g wet material with 100 nd water in a blender at full speed for 2 minutes. The contents were filtered through four layers of cheesecloth and the filtrate was subjected to measurements of pH (electrometricaUy), volatile fatty acids (Erwin et at, 1961), lactic acid (Barker and Summerson, 1941, as modified by Pennington and Sutherland, 1956) and watersoluble carbohydrate content (Dubois et al, 1956, as adapted to corn plants by Johnson et at, 1966a). All chemical analyses were conducted in duplicate. Counts f?r total bacteria and coliforms were determined on aseptically prepared water extracts plated and cultured according to the standard method for testing pasteurized milk (Anonymous, 1967). A range of dilutions was plated and all within the limits of the Quebec Colony Counters (up to 300 colonies per plate) were counted. Statistical Treatment All data were analyzed by least squares analysis o f variance (Ostle, 1963). The multiple range test of Duncan (1955) was used to test for significant differences among means. s American Optical Corp., Buffalo, N.Y.
Results and Discussion Composition of Broiler Litter and Initial Forage. The chemical composition of the broiler litter used in these studies is presented in table 1. Dry matter content of the l0 samples averaged 82.92%. The crude protein content of 26.75%, dry basis, was somewhat lower than litter used previously in this laboratory (Bhattacharya and Fontenot, 1965, 1966; Fontenot et aL, 1971). A factor probably contributing to the low crude protein content was the high crude fiber value of 23%, indicating that the litter contained a considerably higher proportion of the original base material than in previous studies, thus diluting the accumulation of excreta, feathers and wasted feed. Ammonia nitrogen, .98% of dry matter and 22.90% of total nitrogen, was similar to values reported by Caswell (1972) for unprocessed fitter. Bhattacharya and Fontenot (1965) reported that ammonia nitrogen contributed 13% of the total nitrogen of litter containing 5.1% nitrogen, dry basis. The composition of initial corn forage harvested at two maturities is also presented in table 1. The forage contained 25.22% DM for maturity 1 and 37.68% DM for maturity 2 for the small-bag study. Corn harvested at maturity 1 had significantly more crude protein, crude fiber, ash and water-soluble carbohydrates and less NFE than at maturity 2. Forage contained 32.38% and 23.36% water-soluble carbohy-
Downloaded from https://academic.oup.com/jas/article-abstract/40/1/144/4668045 by University of Wyoming Libraries user on 19 June 2018
ENSILED BROILER LITTER AND CORN FORAGE
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Downloaded from https://academic.oup.com/jas/article-abstract/40/1/144/4668045 by University of Wyoming Libraries user on 19 June 2018
147
148
HARMON, FONTENOT AND WEBB, JR.
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drates at maturities 1 and 2, respectively. These values show a similar response to maturity as those reported by Johnson et aL (1966a) who observed that whole corn plants containing 25 to 30% DM contained about 30% soluble carbohydrate, and corn plants of 40% Dirt had 25% soluble carbohydrate, dry basis. The crude protein content of corn forage decreased from 8.25% for maturity 1 to 7.28% for maturity 2. Johnson et al (1966b) also observed decreased crude protein of corn forage with maturity after corn plants reached about 30% DM. The decrease in crude fiber and increase in NFE with respect to maturity can be explained by the fact that as the corn plant matures the grain contributes proportionately more of the total dry matter of the plant (Johnson et aL, 1966b). The composition of initial forage for the large-bag study shows similar values as for the small-bag study. Differences between maturities were significant for all components measured. _ Composition of Initial Mixture~ The chem9 ical composition of the initial mixtures of corn v forage and corn forage plus urea or litter for the ~, small-bag study is presented in table 2 and for ~ the large-bag study, in table 3. Values for the i small-bag study (table 2) represent the average r~ of two replicate samples per silage. Dry matter content of small-bag mixtures was significantly increased by advancing corn !~ forage maturity and by each level of broiler litter addition. Percentages of crude protein and ash were also significantly affected by maturity and level of litter addition. A significant depression in water-soluble carbohydrate was noted for advancing maturity of the corn plant and for each level of litter addition. Johnson et (1966a) observed a reduction in watersoluble carbohydrate with advancing corn plant maturity. The depression ~ssociated with litter addition was expected since the litter contained only about 4.4% water soluble carbohydrate, dry basis. I The composition of initial mixtures for the large-bag study is presented in table 3, the values representing the average of eight samples per silage. Generally, the values for a particular ~ mixture corresponded closely with values of the i corresponding small-bag mixture. Composition and Fermentation Characteris~ticsofSilage~Thecompositionofensiledcorn forage and mixtures of corn forage plus urea or ~ broiler litter is presented in tables 4 and 5 for the small-bag and large-bag studies, respectively. [~ The values in table 4 for the small-bag study represent the average of six replicate samples of -z each silage. Dry matter was significantly increased by advancing maturity of the corn
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ENSILED BROILER LITTER AND CORN FORAGE
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T A B L E 6. T O T A L AND AMMONIA N I T R O G E N OF INITIAL AND F E R M E N T E D M A T E R I A L , SMALL-BAG STUDY
Silage
Total nitrogen, % of DM
Ammonia nitrogen, % of total nitrogen !
Maturity
Treatment
1 1 1 1 1
Control Urea Litter Litter-30 Litter-45
2 2 2 2 2"
Control Urea Litter-15 Litter-30 Litter-45
Initiala
Fermenteda
Initial
Fermentedb
1.32d 2.14 h 1.98g 2.42i 2.94k
1.42d 2.33h 1.99g 2.52i 3.01k
2.82c 5.17d 11.08 e 14.48g 17.04h
5.34e 8.09 d 12.04 e 16.49 f 19.88h
1.24c 1.78 f 1.68 e 1.97g 2.70]
1.21e 1.84 f 1.70e 2.31h 2.80 J
2.55 e 10.31 e 10.04e 12.44f 16.02h
5.08e 12.17 9 12.19e 16.48f 17.75g
aWhen statistically analyzed over b o t h stages of matuzity, values were al_m~ifleantlu affected (P < .01) b y maturity. b W h e n statiz~cally analyzed over b o t h stages of m a t t ~ t y , values were s/gniflcantly affected (P
