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Nitrogen balance and abomasal protein-nitrogen flow in growing ruminants fed methane digester effluent in combination with distillers dried grains
Animal Feed Science and Technology, 13 (1985) 47--55 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
47
NITROGEN BALANCE AND ABOMASAL PROTEIN-NITROGEN FLOW IN GROWING RUMINANTS FED METHANE DIGESTER E F F L U E N T IN COMBINATION WITH DISTILLERS DRIED GRAINS ~
F.K. GOEDEKEN 2, J.A. PATERSON, L.L. K O E L N 3, J.R. FISCHER 4 and J.E. WILLIAMS
Department of Animal Science, University of Missouri, Columbia 65211 MO (U.S.A.) (Received 1 June 1984; accepted for publication 12 March 1985)
ABSTRACT
Goedeken, F.K., Paterson, J.A., Koeln, L.L., Fischer, J.R. and Williams, J.E., 1985. Nitrogen balance and abomasal protein-nitrogen flow in growing ruminants fed methane digester effluent in combination with distillers dried grains. Anim. Feed Sci. Technol., 13: 47--55. Two experiments were conducted to compare dry matter and nitrogen (N) digestibilities, N balance (heifers and lambs) and abomasal N flow (lambs) of ruminants offered ensiled, cracked maize--maize cob diets supplemented with either methane digester effluent (MDE), distillers dried grains (DDG), MDE + DDO (50% of the supplemental N from each) or soyabean meal (SBM). Dry matter digestibility of the diets w a s similar (avg. 68.4%, heifer; 65.4%, lambs), but N digestibility was lowest (P < 0.05) for MDE (54.6%, heifers) and highest for SBM (65.2%, heifers; 64.8%, lambs). Nitrogen digestibilities were similar (P ~ 0.10) between MDE and DDG (58.5 vs. 57.7%) when lambs ware utilized. Nitrogen balance was lower for MDE (6.0 g/day, heifers; 1.8 g/day, lambs) compared with DDG (16.4 g/day, heifer; 3.3 g/day, lambs) but the MDE + DDG combination resulted in an increased balance similar (P :> 0.10) to that of SBM (13.3 g/day, heifers; 3.2 g/day, lambs). Total IN flowing past the abomasum was lowest for MDE (14.6 g/day) and highest for DDG (16.9 g/day) with intermediate values observed for MDE + DDG (16.2 g/day) and SBM (15.1 g/day). No differences in nonprotein N flow rates were measured (avg. 7.0 g/day) but protein N flow was lower (P < 0.10) for MDE (6.8 g/day) compared with DDG (9.4 g/day). Higher quantities o f total abomasal N appeared to be associated with the protein N fraction. Adding DDG to MDE resulted in a protein N flow rate similar to SBM (7.8 vs. 7.5 g/day). These data indicate that N balance was lower for MDE compared with DDG, MDE + DDG or SBM and may he the result of a reduction in quantity of protein N presented to the small intestine. Replacing 50% o f the supplemental N supplied by MDE with DDG increased N balance and abomasal protein N flow to a level equivalent w i t h SBM.
i Contribution o f the Missouri Agricultural Experiment Station Journal Series No. 9783. 2 Department o f Animal Science, University of Nebraska, Lincoln 68583, NE, U.S.A. 3 Continental Grain Company, LibertyviUe, IL 60048, U.S.A. 4 Department of Agricultural Engineering, ARS, USDA, U.S.A.
0377-8401/85/$03.30
© 1985 Elsevier Science Publishers B.V.
48 INTRODUCTION Methane digester effluent (MDE), the immediate byproduct of anerobic fermentation of livestock manure to produce methane biogas, can be utilized as a supplemental N source in ruminant diets (Prior and Hashimoto, 1981; Goedeken, 1984). The increased cost of fossil fuels has promoted the development of anerobic digesters that can produce methane gas efficiently from manure in order to supplement fossil fuels. Iannotti et al. (1979) reported that the MDE produced from swine manure contained 2.8% organic N, 8.5% ammonia N and 11.4% total N. Reduced rate and efficiency of gain has been reported when MDE replaced soyabean meal in diets for growing ruminants (Prior et al., 1980). This reduction in performance was also confirmed when MDE or urea was compared with natural protein sources (Goedeken, 1984). Combining slowly degradable protein sources such as distillers dried grains (DDG) with urea in diets for growing ruminants can reduce feed cost without reducing performance when compared to soyabean meal supplemented diets. Diets containing DDG and urea (with each contributing 50% of the supplemental protein) have produced superior or equivalent gains to that of soyabean meal when fed to calves (Klopfenstein et al., 1978). This research was conducted to evaluate N balance and protein flow to the small intestine when MDE was fed in combination with DDG and compared with N supplementation from MDE, DDG or soyabean meal (SBM). MATERIALS AND METHODS
Silage preparation An on-farm methane digester which utilized cattle and swine manure produced the MDE (2.7% dry matter and 30% crude protein) used in the heifer metabolism trial. For the lamb trial MDE was obtained from two experimental methane fermenters described by Fischer et al. (1979) which utilized swine manure as an energy substrate. Compositions of the two MDE are presented in Table I. Nitrogen and mineral analysis were conducted according to Association of Official Analytical Chemists (1975) procedures, while fiber components were determined by the procedures of Goering and Van Soest (1970). In vitro dry matter disappearance was measured using the Moore modification of the TiUey and Terry procedure (Harris, 1970). Ground maize cobs and cracked maize were combined with water (control silage) or MDE and ensiled for 48 days at 68% moisture in 208-i steel drums double lined with polyethylene bags. Diets (Table II) were formulated to be isonitrogenous (10.5% crude protein) and isocaloric (66% total digestible nutrients; TDN) after supplementation. The control silage was combined with DDG, DDG mixed with MDE silage (DDG and MDE each contributed 50% of the supplemental N) or SBM at time of feeding.
49 TABLE I Average composition of methane digester effluent utilized in heifer and lamb metabolism trials Item
Heifer trial
Lamb trial
2.7
3.4
Composition of dry matter Organic matter (%) Crude protein (%) Nitrogen (%1) Acid detergent fiber N (%) Acid detergent fiber (%) Acid detergent lignin (%) Calcium (%) Phosphorus (%) Magnesium (%) Potassium (%)
65.8 27.5 4.4 0.36 11.29 3.83 5.14 5.01 1.42 3.62
63.3 24.5 3,98 0.34 6.94 3.30 5.27 5.16 1.35 3.64
In vitro dry matter disappearance (%)
54.4
55.3
Dry matter (%)
1 Iannotti et al. (1979) determined that of the total N in the as-fed material, 75% was in the form of NI-I~ N and 25% was organic N. T A B L E II Composition of diets fed in heifer and lamb trials Ingredient
Maize, cracked (IFN 4-02-932) Maize cobs, ground (IFN 1-02-782) Methane digester effluent Soya bean meal (IFN 5-04-604) Distillers dried grains (IFN 5-02-842)
Treatment (%)1 MDE
DDG
MDE + DDG
SBM
50
31.85
40.88
33.90
42
50.45
45.33 4.18
53.69
8
12.41 17.69
9.61
i Dry matter basis.
Heifer trial T w o r e p l i c a t i o n s o f t h e h e i f e r trial w e r e c o n d u c t e d . T h e first replicate c o n s i s t e d o f 12 c r o s s b r e d ( H e r e f o r d × A n g u s X S i m m e n t a l ) heifers averaging 2 2 7 kg w h i c h were r a n d o m l y a l l o t t e d t o s u p p l e m e n t a l p r o t e i n t r e a t m e n t s .
50 Following completion of the first replicate, eight of the heifers were reassigned to treatments with the restriction that no heifer received the same diet in both periods. Animals were offered similar quantities of dry matter (DM) daily and trace mineralized salt was provided ad libitum in block form. Fresh water was available at all times. Orts were collected daily and cornposited for each animal. Each replicate consisted of a 10-day pre-feeding period followed by 5 days of total feces and urine collection. Daily urine output, obtained by catheterization, (collected under acidic conditions; 50 ml of 10 N H2SO4) was recorded and a 5% aliquot was stored (4°C) for future analysis. Fecal output, collected dally, was stored at 4°C and composited by animal at the end of each collection period. Composited feces were mixed thoroughly in a horizontal mixer and subsampled for analysis. Fresh feed samples, orts and feces were analyzed for DM (55°C, 48 h) and Kjeldahl N (Association of Official Analytical Chemists, 1975) while urine was analyzed for Kjeldahl N only. Intake, digestibility and N balance data were analyzed according to the least squares mean procedure of Barr et al. (1979). The model consisted of main effects of treatment and period and the interaction, treatment × period. When the period and interaction were nonsignificant (P > 0.10) they were dropped from the model. Treatment means were compared only if the overall F value was significant (P < 0.05). Lamb trial Four crossbred wether lambs (avg. wt. 35 kg) fitted with abomasal cannulae were randomly assigned to blocks of a 4 × 4 Latin square. Diets were similar to the preceding trial and were fed twice daily at a restricted level to promote equivalent DM intakes (700 g/day). Chromic oxide (Cr203) was used as an external marker to estimate digesta flow. A premix containing Cr203, salt and minerals (Table III) was hand mixed (10 g/feeding) with corresponding diets at time of feeding. Each period consisted of 7 days prefeeding, 5 days total fecal and urine collection followed by 4 days of abomasal sampling. Feed, fecal and urine samples were obtained, stored and analyzed in a similar manner as in the preceding metabolism trial. Abomasal samples were obtained over 4 days with a minimum of a 9 h interval between sampling to provide samples for every third hour of a 24oh period. Abomasal digesta samples, collected by spontaneous flow into plastic containers, were immediately stored at -10°C. Digesta samples were composited by weight to yield individual animal composites representing a 24-h day. Composited samples were analyzed for total Kjeldahl N and DM (lyophilization; Model No. 6206-0605, VirTis Co. Inc., Gardiner, NY 12525). Nonprotein N content of composited abomasal samples was determined on supernatants following precipitation of protein N with hot (90°C) 10% trichloroacetic acid. Protein N was determined by difference. Dried digesta was analyzed for Cr203 (Hill and Anderson, 1958) and acid detergent insoluble N (ADIN; Goering and Van Soest, 1 9 7 0 ) .
51 TABLE HI Composition: of chromic oxide premix added to lamb diets at time of feeding Ingredient
Chromic oxide Salt, trace mineralized2 Ground maize (IFN 4-02-932) Dried Molasses (IFN 4-00-668) Limestone (IFN 6-02-632)
Treatment (%)~ MDE
DDG
MDE + DDG
SBM
10 10
10 10
10 10
10 10
40
29.5
35.75
29.5
40
29.5
35.75
29.5
21
8.5
21
Percentage of dry matter. Contained 98% NaCl, 0.35% Zn, 0.28% Mn, 0.18% Fe, 0.04% Cu.
Data were analyzed b y Latin square procedures described by Steele and Torrie (1960). Treatment means were compared by the least squares difference if the overall F values were significant (P < 0.10). RESULTS AND DISCUSSION
Heifer trial Dry matter and N c o n t e n t o f silages used in this trial are presented in Table I V . Nitrogen content of the MDE silage was lower than the calculated value ( 8 . 2 vs. 10.5%), consequently, N intake (Table V) was lowest for animals consuming diets containing MDE even though DM intake was similar to that of animals offered DDG diets. Dry matter consumption was lower for TABLE IV Chemical composition of silages used in heifer and lamb metabolism trials Item
Heifer trial Dry matter (%) Crude protein (%)1 Lamb trial Dry matter (%) Crude protein (%)1 i Dry matter basis.
Silage Control
MDE
31.2 6.2
35.1 8.2
37.1 5.1
34.9 9.9
52 TABLE V
Dry matter and N digestibility and N balance of heifers fed ensiled maize and maize cob diets supplemented with methane digester effluent (MDE), distillers dried grains (DDG), methane digester effluent plus distillers dried grains (MDE + DDG) or soyahean meal (SBM) Item
Treatment
SIaM
MDE
DDG
5
5
5
4110 I'2 54.93
43701 72.91
4140 I'2 61.62
Apparent digestibility (%) Dry matter Nitrogen
69.1 54.63
67.3 59.62
N balance (g/day) % N retained
6.03 11.1:
16.41 22.51
No. heifers Intake (g/day) Dry matter Nitrogen 4
MDE + DDG
SBM 5
39302 72.51
12.4 1.41
68.7 57.92', 3
68.3 65.21
2.21 1.49
12.72 20.71
13.31'= 18.31
1.28 2.03
1,2.SMeans in the same row with unlike superscripts differ (P < 0.05). 4 Period effect (P < 0.01) and period × treatment interaction (P < 0.05).
SBM diet when compared to DDG diet b u t was similar to diets containing MDE. A treatment × period interaction was observed for N intake ( P < 0.O5). Animals offered DDG, MDE + DDG or SBM consumed less N during the second period when compared to the first, while those offered MDE consumed more N during the second period than the first. Nitrogen intake for heifers offered MDE was significantly lower t h r o u g h o u t the trial due to the low N content of the silage. D r y matter digestibility was similar (P > 0.10) for all treatments (avg. 69.4%) while N digestibility was highest for heifers offered SBM (65.2%) and lowest for those receiving MDE (54.6%). The combination of MDE and DDG resulted in intermediate digestibilities indicating no associative effects. Nitrogen balance was greatest in DDG fed heifers (16.4 g/day) and lowest for heifers receiving MDE silage alone (6.0 g/day) reflecting N intake. When expressed as a percentage of N retained, heifers consuming diets with DDG or SBM retained more than those offered MDE silage alone (avg. 20.5 vs. 11.1%). The lower N digestibility and N balance in lambs fed MDE compared with natural protein sources was also reported by Prior et al. (1980) and G o e d e k e n (1984). Adding D D G to MDE did increase the percentage of N retained to a level similar to that of DDG and SBM. If it is assumed that the N value of MDE is similar to urea, then this data is analogous to that of Klopfenstein et al. (1978) w h o f o u n d a 53% increase in N retention when D D G replaced two-thirds of the supplemental N supplied by urea when offered to growing lambs.
53
L a m b trial Dry matter and crude protein contents of silages offered to lambs are presented in Table IV. Dry matter intake was highest for lambs offered DDG and lowest for lambs offered MDE even though intake was restricted and all animals were offered similar quantities of DM daffy (Table VI). As in the heifer metabolism trial, no differences were observed in DM digestibility among diets (avg. 65.4%). Nitrogen digestibility was similar (P > 0.10) f o r MDE and DDG diets (avg. 58.1%) b u t greater for the SBM diet (64.8%). Although N digestibility of the MDE + D D G combination diet was n o t statistically different from either the MDE or DDG diets alone, it was similar (P > 0.10) to SBM supplemented silage. Statistically these results are different from that for the heifer trial where SBM was superior to MDE + DDG. However, in both trials SBM appears to be a somewhat better protein source than does the combination of MDE + DDG. This m a y be due to the lower total N c o n t e n t of the diet or source of manure utilized in the digester. In addition, it is unknown, at present, h o w a longer adaptation period to the diets m a y have affected these variables, since lambs were adapted for only 10 days prior t o sample collection. Nitrogen balance was lowest (P < 0.05) in lambs fed MDE (1.8 g/day) b u t similar among the other treatments (avg. 3.1 g/day). TABLE VI Intake, digestibility and N balance of lambs fed ensiled cracked maize and ground maize cobs supplemented with methane digester effluent (MDE), distillers dried grains (DDG), methane digester effluent plus distillers dried grains (MDE + DDG) or soyabean meal (SBM) Item
Treatment MDE
No. lambs Intake (g/day) Dry matter Nitrogen Apparent digestibility (%) Dry matter Nitrogen
4
709' 11.23
SEM DDG
4
7373 112
MDE + DDG
SBM
4
4
7222 11.23
7262 10.71
3.6 0.07
69.2 64.82
3.41 1.96
62.9 58.51
62.5 57.71
68.9 60.21'2
Nitrogen excretion (g/day) Urine Feces
4.82 4.72
3.0' 4.62
3.61 4.72
3.8 ''2 3.8'
0.39 0.22
Nitrogen balance (g/day)
1.81
3.32
2.92
3.22
0.33
~'2'SMeans i n t h e same row with unlike superscriPts differ (P < 0.05).
a
This lower N balance reflected the lower N intake and higher urinary N excretion. Similar results were reported by Goedeken et al. (1985) who found that N balance in lambs was lower for MDE (0.05 g/day) compared with lambs offered SBM (0.49 g/day) or DDG (0.64 g/day). Replacing one-half of the MDE with DDG resulted in a 61% increase in N balance (2.9 vs. 1.8 g/ day). Although lambs receiving MDE consumed similar quantities of dietary N as lambs offered the other diets, numerically less total N and protein N reached the small intestine(Table VII). Higher quantities of total abomasal N appeared to be associated with the protein N fraction. The similarity in N flow for DDG, MDE + DDG and SBM is in agreement with the similar N balance in lambs offered these diets. Although not statistically different, diets containing the slowly degradable protein source, DDG, resulted in higher concentrations of ADIN (0.9 vs. 0.7 g/day) flowing past the abomasum. The increase in abomasal protein N flow for the DDG diet compared with the MDE diet may be a result of lower ruminal degradation of the DDG protein (Klopfenstein and Abrams, 1981). Muntifering et al. (1983) reported an increase in daily abomasal protein N for DDG plus solubles compared with SBM. In the present study it appeared that more protein N was presented to the abomasum with DDG compared with SBM, but the data were not statistically different (P :> 0.10). Rate and efficiency of gain reported by Goedeken et al. (1985) was higher when lambs were offered distillers wet grains compared with those which received MDE and may be correlated with the lower N balance and tendency of lower abomasal N in lambs receiving MDE in the current study. TABLE VII Nitrogen intake and daily N flow through the abomasum of lambs fed ensiled cracked maize and ground maize cobs supplemented with methane digester effluent (MDE), distillers dried grains (DDG), methane digester effluent plus distillers dried grains (MDE + DDG) or soyabean meal (SBM) Item
Nitrogen intake Abomasal nitrogen Total Protein Nonprotein Acid detergent insoluble N
Treatment (g/day)
SEM
MDE
DDG
MDE + DDG
SBM
11
11.1
11.1
11
0.19
14.73 6.81 7.1
16.94 9.42 6.6
16.23,4 7.81': 7.5
15.1 ~.4 7.51'2'3 7
1.06 0.72 0.58
0.7
0.9
0.9
1,2M e a n s in the same r o w with unlike superscripts differ (P < 0.05). 3,4M e a n s in the same r o w with unlike superscripts differ (P < 0.10).
0.6
0.17
55
Feeding MDE silage to heifers and lambs appears to result in decreased N balance and digestibility when compared with feeding silages supplemented with DDG or SBM. Observations in lambs showed a reduction in abomasal protein N flow when MDE was compared with DDG. However, replacing 50% of the supplemental N from MDE with DDG resulted in similar N utilization in heifers and lambs and abomasal protein N flow in lambs fed SBM or MDE + DDG.
REFERENCES Association of Official Analytical Chemists, 1975. Official Methods of Analysis, 12th edn. A.O.A.C., Washington, DC. Barr, A.J., Goodnight, J.H., Sall, J.P., Blain, W.H., Chilko, D.M., Council, K.A. and Helwig, J.T., 1979. SAS User's Guide. SAS Institute, Inc., Raleigh, N C . Fischer, J.R., Iannotti, E.L., Porter, J.H. and Garcia, A.B., 1979. Producing methane gas in a pilot~size digester. Trans. Am. Soc. Agric. Eng., 22: 370--374. Goedeken, F.K., 1984. Utilization of methane digester effluent in ruminant diets. M.S. Thesis. University of Missouri, Columbia. Goedeken, F.K., Paterson, J.A., Koeln, L.L., Fischer, J.R. and Williams, J.E., 1985. Rumen fermentation characteristics, nitrogen balance and growth in lambs fed methane digester effluent. J. Anita. Sci., accepted for publication. Goering, J.K. and Van Soest, P.J., 1970. Forage Fiber Analysis (Apparatus, Reagents, Procedures and Some Application). USDA Agr. Handbook, No. 379. Washington DC. Harris, L.L., 1970. Nutrition Research Techniques for Domestic and Wild Animals, Vol. 1, Utah State University, Logan, p. 4990. Hill, F.W. and Anderson, D.L., 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr., 64: 587--603. Iannotti, E.L., Porter, J.H., Fischer, J.R. and Seivers, D.M., 1979. Changes in swine manure during anerobic!digestion. Dev. Ind. Microbiol., 20: 519--529. Klopfenstein, T.J. and Abrams, S.M., 1981. Distillers byproducts use -- a review. Nebraska Beef Cattle Rep. EC81-218, pp. 2--3. Klopfenstein, T.J., Waller, J.E., Merchen, N. and Peterson, L., 1978. Distillers grains as naturally protected protein for ruminants. Proc. Distillers Feed Res. Counc., 33: 38-41. Muntifering, R.B., Burch, T.J., Miller, B.G. and Ely, D.G., 1983. Digestibility and metabolism of mature tall fescue hay reconstituted and ensiled with whole stillage. J. Anita. Sci., 57: 1286--1293. Prior, R.L. and Hashimoto, A.G., 1981. Potential for fermented cattle residue as a feed ingredient for livestock. In: D.L. Wise (Editor), Fuel Gas Production from Biogas, Vol. 2, CRC Press, Boca Raton, FL, pp. 215--237. Prior, R.L., Britton, R.A. and I-Iashimoto, A.G., 1980. Nutritional value of anaerobically fermented beef wastes in diets for beef cattle and sheep. In: Livestock Waste: A Renewable Resource. Fourth Int. Syrup. Livestock Wastes. Am. Soc. Agric. Eng. Publ. Proc., pp. 54--60. Steel, R.G.D. and Torrie, J.H., 1960. Principles and Procedures of Statistics. McGraw-Hill, New York.
47
NITROGEN BALANCE AND ABOMASAL PROTEIN-NITROGEN FLOW IN GROWING RUMINANTS FED METHANE DIGESTER E F F L U E N T IN COMBINATION WITH DISTILLERS DRIED GRAINS ~
F.K. GOEDEKEN 2, J.A. PATERSON, L.L. K O E L N 3, J.R. FISCHER 4 and J.E. WILLIAMS
Department of Animal Science, University of Missouri, Columbia 65211 MO (U.S.A.) (Received 1 June 1984; accepted for publication 12 March 1985)
ABSTRACT
Goedeken, F.K., Paterson, J.A., Koeln, L.L., Fischer, J.R. and Williams, J.E., 1985. Nitrogen balance and abomasal protein-nitrogen flow in growing ruminants fed methane digester effluent in combination with distillers dried grains. Anim. Feed Sci. Technol., 13: 47--55. Two experiments were conducted to compare dry matter and nitrogen (N) digestibilities, N balance (heifers and lambs) and abomasal N flow (lambs) of ruminants offered ensiled, cracked maize--maize cob diets supplemented with either methane digester effluent (MDE), distillers dried grains (DDG), MDE + DDO (50% of the supplemental N from each) or soyabean meal (SBM). Dry matter digestibility of the diets w a s similar (avg. 68.4%, heifer; 65.4%, lambs), but N digestibility was lowest (P < 0.05) for MDE (54.6%, heifers) and highest for SBM (65.2%, heifers; 64.8%, lambs). Nitrogen digestibilities were similar (P ~ 0.10) between MDE and DDG (58.5 vs. 57.7%) when lambs ware utilized. Nitrogen balance was lower for MDE (6.0 g/day, heifers; 1.8 g/day, lambs) compared with DDG (16.4 g/day, heifer; 3.3 g/day, lambs) but the MDE + DDG combination resulted in an increased balance similar (P :> 0.10) to that of SBM (13.3 g/day, heifers; 3.2 g/day, lambs). Total IN flowing past the abomasum was lowest for MDE (14.6 g/day) and highest for DDG (16.9 g/day) with intermediate values observed for MDE + DDG (16.2 g/day) and SBM (15.1 g/day). No differences in nonprotein N flow rates were measured (avg. 7.0 g/day) but protein N flow was lower (P < 0.10) for MDE (6.8 g/day) compared with DDG (9.4 g/day). Higher quantities o f total abomasal N appeared to be associated with the protein N fraction. Adding DDG to MDE resulted in a protein N flow rate similar to SBM (7.8 vs. 7.5 g/day). These data indicate that N balance was lower for MDE compared with DDG, MDE + DDG or SBM and may he the result of a reduction in quantity of protein N presented to the small intestine. Replacing 50% o f the supplemental N supplied by MDE with DDG increased N balance and abomasal protein N flow to a level equivalent w i t h SBM.
i Contribution o f the Missouri Agricultural Experiment Station Journal Series No. 9783. 2 Department o f Animal Science, University of Nebraska, Lincoln 68583, NE, U.S.A. 3 Continental Grain Company, LibertyviUe, IL 60048, U.S.A. 4 Department of Agricultural Engineering, ARS, USDA, U.S.A.
0377-8401/85/$03.30
© 1985 Elsevier Science Publishers B.V.
48 INTRODUCTION Methane digester effluent (MDE), the immediate byproduct of anerobic fermentation of livestock manure to produce methane biogas, can be utilized as a supplemental N source in ruminant diets (Prior and Hashimoto, 1981; Goedeken, 1984). The increased cost of fossil fuels has promoted the development of anerobic digesters that can produce methane gas efficiently from manure in order to supplement fossil fuels. Iannotti et al. (1979) reported that the MDE produced from swine manure contained 2.8% organic N, 8.5% ammonia N and 11.4% total N. Reduced rate and efficiency of gain has been reported when MDE replaced soyabean meal in diets for growing ruminants (Prior et al., 1980). This reduction in performance was also confirmed when MDE or urea was compared with natural protein sources (Goedeken, 1984). Combining slowly degradable protein sources such as distillers dried grains (DDG) with urea in diets for growing ruminants can reduce feed cost without reducing performance when compared to soyabean meal supplemented diets. Diets containing DDG and urea (with each contributing 50% of the supplemental protein) have produced superior or equivalent gains to that of soyabean meal when fed to calves (Klopfenstein et al., 1978). This research was conducted to evaluate N balance and protein flow to the small intestine when MDE was fed in combination with DDG and compared with N supplementation from MDE, DDG or soyabean meal (SBM). MATERIALS AND METHODS
Silage preparation An on-farm methane digester which utilized cattle and swine manure produced the MDE (2.7% dry matter and 30% crude protein) used in the heifer metabolism trial. For the lamb trial MDE was obtained from two experimental methane fermenters described by Fischer et al. (1979) which utilized swine manure as an energy substrate. Compositions of the two MDE are presented in Table I. Nitrogen and mineral analysis were conducted according to Association of Official Analytical Chemists (1975) procedures, while fiber components were determined by the procedures of Goering and Van Soest (1970). In vitro dry matter disappearance was measured using the Moore modification of the TiUey and Terry procedure (Harris, 1970). Ground maize cobs and cracked maize were combined with water (control silage) or MDE and ensiled for 48 days at 68% moisture in 208-i steel drums double lined with polyethylene bags. Diets (Table II) were formulated to be isonitrogenous (10.5% crude protein) and isocaloric (66% total digestible nutrients; TDN) after supplementation. The control silage was combined with DDG, DDG mixed with MDE silage (DDG and MDE each contributed 50% of the supplemental N) or SBM at time of feeding.
49 TABLE I Average composition of methane digester effluent utilized in heifer and lamb metabolism trials Item
Heifer trial
Lamb trial
2.7
3.4
Composition of dry matter Organic matter (%) Crude protein (%) Nitrogen (%1) Acid detergent fiber N (%) Acid detergent fiber (%) Acid detergent lignin (%) Calcium (%) Phosphorus (%) Magnesium (%) Potassium (%)
65.8 27.5 4.4 0.36 11.29 3.83 5.14 5.01 1.42 3.62
63.3 24.5 3,98 0.34 6.94 3.30 5.27 5.16 1.35 3.64
In vitro dry matter disappearance (%)
54.4
55.3
Dry matter (%)
1 Iannotti et al. (1979) determined that of the total N in the as-fed material, 75% was in the form of NI-I~ N and 25% was organic N. T A B L E II Composition of diets fed in heifer and lamb trials Ingredient
Maize, cracked (IFN 4-02-932) Maize cobs, ground (IFN 1-02-782) Methane digester effluent Soya bean meal (IFN 5-04-604) Distillers dried grains (IFN 5-02-842)
Treatment (%)1 MDE
DDG
MDE + DDG
SBM
50
31.85
40.88
33.90
42
50.45
45.33 4.18
53.69
8
12.41 17.69
9.61
i Dry matter basis.
Heifer trial T w o r e p l i c a t i o n s o f t h e h e i f e r trial w e r e c o n d u c t e d . T h e first replicate c o n s i s t e d o f 12 c r o s s b r e d ( H e r e f o r d × A n g u s X S i m m e n t a l ) heifers averaging 2 2 7 kg w h i c h were r a n d o m l y a l l o t t e d t o s u p p l e m e n t a l p r o t e i n t r e a t m e n t s .
50 Following completion of the first replicate, eight of the heifers were reassigned to treatments with the restriction that no heifer received the same diet in both periods. Animals were offered similar quantities of dry matter (DM) daily and trace mineralized salt was provided ad libitum in block form. Fresh water was available at all times. Orts were collected daily and cornposited for each animal. Each replicate consisted of a 10-day pre-feeding period followed by 5 days of total feces and urine collection. Daily urine output, obtained by catheterization, (collected under acidic conditions; 50 ml of 10 N H2SO4) was recorded and a 5% aliquot was stored (4°C) for future analysis. Fecal output, collected dally, was stored at 4°C and composited by animal at the end of each collection period. Composited feces were mixed thoroughly in a horizontal mixer and subsampled for analysis. Fresh feed samples, orts and feces were analyzed for DM (55°C, 48 h) and Kjeldahl N (Association of Official Analytical Chemists, 1975) while urine was analyzed for Kjeldahl N only. Intake, digestibility and N balance data were analyzed according to the least squares mean procedure of Barr et al. (1979). The model consisted of main effects of treatment and period and the interaction, treatment × period. When the period and interaction were nonsignificant (P > 0.10) they were dropped from the model. Treatment means were compared only if the overall F value was significant (P < 0.05). Lamb trial Four crossbred wether lambs (avg. wt. 35 kg) fitted with abomasal cannulae were randomly assigned to blocks of a 4 × 4 Latin square. Diets were similar to the preceding trial and were fed twice daily at a restricted level to promote equivalent DM intakes (700 g/day). Chromic oxide (Cr203) was used as an external marker to estimate digesta flow. A premix containing Cr203, salt and minerals (Table III) was hand mixed (10 g/feeding) with corresponding diets at time of feeding. Each period consisted of 7 days prefeeding, 5 days total fecal and urine collection followed by 4 days of abomasal sampling. Feed, fecal and urine samples were obtained, stored and analyzed in a similar manner as in the preceding metabolism trial. Abomasal samples were obtained over 4 days with a minimum of a 9 h interval between sampling to provide samples for every third hour of a 24oh period. Abomasal digesta samples, collected by spontaneous flow into plastic containers, were immediately stored at -10°C. Digesta samples were composited by weight to yield individual animal composites representing a 24-h day. Composited samples were analyzed for total Kjeldahl N and DM (lyophilization; Model No. 6206-0605, VirTis Co. Inc., Gardiner, NY 12525). Nonprotein N content of composited abomasal samples was determined on supernatants following precipitation of protein N with hot (90°C) 10% trichloroacetic acid. Protein N was determined by difference. Dried digesta was analyzed for Cr203 (Hill and Anderson, 1958) and acid detergent insoluble N (ADIN; Goering and Van Soest, 1 9 7 0 ) .
51 TABLE HI Composition: of chromic oxide premix added to lamb diets at time of feeding Ingredient
Chromic oxide Salt, trace mineralized2 Ground maize (IFN 4-02-932) Dried Molasses (IFN 4-00-668) Limestone (IFN 6-02-632)
Treatment (%)~ MDE
DDG
MDE + DDG
SBM
10 10
10 10
10 10
10 10
40
29.5
35.75
29.5
40
29.5
35.75
29.5
21
8.5
21
Percentage of dry matter. Contained 98% NaCl, 0.35% Zn, 0.28% Mn, 0.18% Fe, 0.04% Cu.
Data were analyzed b y Latin square procedures described by Steele and Torrie (1960). Treatment means were compared by the least squares difference if the overall F values were significant (P < 0.10). RESULTS AND DISCUSSION
Heifer trial Dry matter and N c o n t e n t o f silages used in this trial are presented in Table I V . Nitrogen content of the MDE silage was lower than the calculated value ( 8 . 2 vs. 10.5%), consequently, N intake (Table V) was lowest for animals consuming diets containing MDE even though DM intake was similar to that of animals offered DDG diets. Dry matter consumption was lower for TABLE IV Chemical composition of silages used in heifer and lamb metabolism trials Item
Heifer trial Dry matter (%) Crude protein (%)1 Lamb trial Dry matter (%) Crude protein (%)1 i Dry matter basis.
Silage Control
MDE
31.2 6.2
35.1 8.2
37.1 5.1
34.9 9.9
52 TABLE V
Dry matter and N digestibility and N balance of heifers fed ensiled maize and maize cob diets supplemented with methane digester effluent (MDE), distillers dried grains (DDG), methane digester effluent plus distillers dried grains (MDE + DDG) or soyahean meal (SBM) Item
Treatment
SIaM
MDE
DDG
5
5
5
4110 I'2 54.93
43701 72.91
4140 I'2 61.62
Apparent digestibility (%) Dry matter Nitrogen
69.1 54.63
67.3 59.62
N balance (g/day) % N retained
6.03 11.1:
16.41 22.51
No. heifers Intake (g/day) Dry matter Nitrogen 4
MDE + DDG
SBM 5
39302 72.51
12.4 1.41
68.7 57.92', 3
68.3 65.21
2.21 1.49
12.72 20.71
13.31'= 18.31
1.28 2.03
1,2.SMeans in the same row with unlike superscripts differ (P < 0.05). 4 Period effect (P < 0.01) and period × treatment interaction (P < 0.05).
SBM diet when compared to DDG diet b u t was similar to diets containing MDE. A treatment × period interaction was observed for N intake ( P < 0.O5). Animals offered DDG, MDE + DDG or SBM consumed less N during the second period when compared to the first, while those offered MDE consumed more N during the second period than the first. Nitrogen intake for heifers offered MDE was significantly lower t h r o u g h o u t the trial due to the low N content of the silage. D r y matter digestibility was similar (P > 0.10) for all treatments (avg. 69.4%) while N digestibility was highest for heifers offered SBM (65.2%) and lowest for those receiving MDE (54.6%). The combination of MDE and DDG resulted in intermediate digestibilities indicating no associative effects. Nitrogen balance was greatest in DDG fed heifers (16.4 g/day) and lowest for heifers receiving MDE silage alone (6.0 g/day) reflecting N intake. When expressed as a percentage of N retained, heifers consuming diets with DDG or SBM retained more than those offered MDE silage alone (avg. 20.5 vs. 11.1%). The lower N digestibility and N balance in lambs fed MDE compared with natural protein sources was also reported by Prior et al. (1980) and G o e d e k e n (1984). Adding D D G to MDE did increase the percentage of N retained to a level similar to that of DDG and SBM. If it is assumed that the N value of MDE is similar to urea, then this data is analogous to that of Klopfenstein et al. (1978) w h o f o u n d a 53% increase in N retention when D D G replaced two-thirds of the supplemental N supplied by urea when offered to growing lambs.
53
L a m b trial Dry matter and crude protein contents of silages offered to lambs are presented in Table IV. Dry matter intake was highest for lambs offered DDG and lowest for lambs offered MDE even though intake was restricted and all animals were offered similar quantities of DM daffy (Table VI). As in the heifer metabolism trial, no differences were observed in DM digestibility among diets (avg. 65.4%). Nitrogen digestibility was similar (P > 0.10) f o r MDE and DDG diets (avg. 58.1%) b u t greater for the SBM diet (64.8%). Although N digestibility of the MDE + D D G combination diet was n o t statistically different from either the MDE or DDG diets alone, it was similar (P > 0.10) to SBM supplemented silage. Statistically these results are different from that for the heifer trial where SBM was superior to MDE + DDG. However, in both trials SBM appears to be a somewhat better protein source than does the combination of MDE + DDG. This m a y be due to the lower total N c o n t e n t of the diet or source of manure utilized in the digester. In addition, it is unknown, at present, h o w a longer adaptation period to the diets m a y have affected these variables, since lambs were adapted for only 10 days prior t o sample collection. Nitrogen balance was lowest (P < 0.05) in lambs fed MDE (1.8 g/day) b u t similar among the other treatments (avg. 3.1 g/day). TABLE VI Intake, digestibility and N balance of lambs fed ensiled cracked maize and ground maize cobs supplemented with methane digester effluent (MDE), distillers dried grains (DDG), methane digester effluent plus distillers dried grains (MDE + DDG) or soyabean meal (SBM) Item
Treatment MDE
No. lambs Intake (g/day) Dry matter Nitrogen Apparent digestibility (%) Dry matter Nitrogen
4
709' 11.23
SEM DDG
4
7373 112
MDE + DDG
SBM
4
4
7222 11.23
7262 10.71
3.6 0.07
69.2 64.82
3.41 1.96
62.9 58.51
62.5 57.71
68.9 60.21'2
Nitrogen excretion (g/day) Urine Feces
4.82 4.72
3.0' 4.62
3.61 4.72
3.8 ''2 3.8'
0.39 0.22
Nitrogen balance (g/day)
1.81
3.32
2.92
3.22
0.33
~'2'SMeans i n t h e same row with unlike superscriPts differ (P < 0.05).
a
This lower N balance reflected the lower N intake and higher urinary N excretion. Similar results were reported by Goedeken et al. (1985) who found that N balance in lambs was lower for MDE (0.05 g/day) compared with lambs offered SBM (0.49 g/day) or DDG (0.64 g/day). Replacing one-half of the MDE with DDG resulted in a 61% increase in N balance (2.9 vs. 1.8 g/ day). Although lambs receiving MDE consumed similar quantities of dietary N as lambs offered the other diets, numerically less total N and protein N reached the small intestine(Table VII). Higher quantities of total abomasal N appeared to be associated with the protein N fraction. The similarity in N flow for DDG, MDE + DDG and SBM is in agreement with the similar N balance in lambs offered these diets. Although not statistically different, diets containing the slowly degradable protein source, DDG, resulted in higher concentrations of ADIN (0.9 vs. 0.7 g/day) flowing past the abomasum. The increase in abomasal protein N flow for the DDG diet compared with the MDE diet may be a result of lower ruminal degradation of the DDG protein (Klopfenstein and Abrams, 1981). Muntifering et al. (1983) reported an increase in daily abomasal protein N for DDG plus solubles compared with SBM. In the present study it appeared that more protein N was presented to the abomasum with DDG compared with SBM, but the data were not statistically different (P :> 0.10). Rate and efficiency of gain reported by Goedeken et al. (1985) was higher when lambs were offered distillers wet grains compared with those which received MDE and may be correlated with the lower N balance and tendency of lower abomasal N in lambs receiving MDE in the current study. TABLE VII Nitrogen intake and daily N flow through the abomasum of lambs fed ensiled cracked maize and ground maize cobs supplemented with methane digester effluent (MDE), distillers dried grains (DDG), methane digester effluent plus distillers dried grains (MDE + DDG) or soyabean meal (SBM) Item
Nitrogen intake Abomasal nitrogen Total Protein Nonprotein Acid detergent insoluble N
Treatment (g/day)
SEM
MDE
DDG
MDE + DDG
SBM
11
11.1
11.1
11
0.19
14.73 6.81 7.1
16.94 9.42 6.6
16.23,4 7.81': 7.5
15.1 ~.4 7.51'2'3 7
1.06 0.72 0.58
0.7
0.9
0.9
1,2M e a n s in the same r o w with unlike superscripts differ (P < 0.05). 3,4M e a n s in the same r o w with unlike superscripts differ (P < 0.10).
0.6
0.17
55
Feeding MDE silage to heifers and lambs appears to result in decreased N balance and digestibility when compared with feeding silages supplemented with DDG or SBM. Observations in lambs showed a reduction in abomasal protein N flow when MDE was compared with DDG. However, replacing 50% of the supplemental N from MDE with DDG resulted in similar N utilization in heifers and lambs and abomasal protein N flow in lambs fed SBM or MDE + DDG.
REFERENCES Association of Official Analytical Chemists, 1975. Official Methods of Analysis, 12th edn. A.O.A.C., Washington, DC. Barr, A.J., Goodnight, J.H., Sall, J.P., Blain, W.H., Chilko, D.M., Council, K.A. and Helwig, J.T., 1979. SAS User's Guide. SAS Institute, Inc., Raleigh, N C . Fischer, J.R., Iannotti, E.L., Porter, J.H. and Garcia, A.B., 1979. Producing methane gas in a pilot~size digester. Trans. Am. Soc. Agric. Eng., 22: 370--374. Goedeken, F.K., 1984. Utilization of methane digester effluent in ruminant diets. M.S. Thesis. University of Missouri, Columbia. Goedeken, F.K., Paterson, J.A., Koeln, L.L., Fischer, J.R. and Williams, J.E., 1985. Rumen fermentation characteristics, nitrogen balance and growth in lambs fed methane digester effluent. J. Anita. Sci., accepted for publication. Goering, J.K. and Van Soest, P.J., 1970. Forage Fiber Analysis (Apparatus, Reagents, Procedures and Some Application). USDA Agr. Handbook, No. 379. Washington DC. Harris, L.L., 1970. Nutrition Research Techniques for Domestic and Wild Animals, Vol. 1, Utah State University, Logan, p. 4990. Hill, F.W. and Anderson, D.L., 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr., 64: 587--603. Iannotti, E.L., Porter, J.H., Fischer, J.R. and Seivers, D.M., 1979. Changes in swine manure during anerobic!digestion. Dev. Ind. Microbiol., 20: 519--529. Klopfenstein, T.J. and Abrams, S.M., 1981. Distillers byproducts use -- a review. Nebraska Beef Cattle Rep. EC81-218, pp. 2--3. Klopfenstein, T.J., Waller, J.E., Merchen, N. and Peterson, L., 1978. Distillers grains as naturally protected protein for ruminants. Proc. Distillers Feed Res. Counc., 33: 38-41. Muntifering, R.B., Burch, T.J., Miller, B.G. and Ely, D.G., 1983. Digestibility and metabolism of mature tall fescue hay reconstituted and ensiled with whole stillage. J. Anita. Sci., 57: 1286--1293. Prior, R.L. and Hashimoto, A.G., 1981. Potential for fermented cattle residue as a feed ingredient for livestock. In: D.L. Wise (Editor), Fuel Gas Production from Biogas, Vol. 2, CRC Press, Boca Raton, FL, pp. 215--237. Prior, R.L., Britton, R.A. and I-Iashimoto, A.G., 1980. Nutritional value of anaerobically fermented beef wastes in diets for beef cattle and sheep. In: Livestock Waste: A Renewable Resource. Fourth Int. Syrup. Livestock Wastes. Am. Soc. Agric. Eng. Publ. Proc., pp. 54--60. Steel, R.G.D. and Torrie, J.H., 1960. Principles and Procedures of Statistics. McGraw-Hill, New York.