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Ensiling of rumen contents and blood with wheat straw
Animal Feed Science and Technology, 18 (1987) 67-73 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
67
E n s i l i n g of R u m e n Contents and Blood with Wheat Straw N. MURALIDHARA RAO1and J.P. FONTENOT Department of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (U.S.A.) (Received 14 March 1986; accepted for publication 22 January 1987)
ABSTRACT
Rao, N.M. and Fontenot, J.P., 1987. Ensiling of rumen contents and blood with wheat straw, Anita. Feed Sci. Technol, 18: 67-73. Rumen contents and whole blood in the ratios 2:1 and 1:1 (w/w) were mixed with ground wheat straw in the proportions of 70:30, 60:40, 50:50 and 40:60 (w/w) with and without dry molasses (5% w/w). The mixtures were ensiled for 6 weeks in polyethylene bags. Weight, pH, dry matter, lactic acid, soluble carbohydrates, volatile fatty acids and crude protein were determined before and after ensiling. All silages had desirable aromas after 6 weeks fermentation, pH was between 4 and 5, and lactic acid and acetic acid levels were sufficient to ensure preservation in most of the ensiled mixtures.
INTRODUCTION R u m e n c o n t e n t s ( R C ) consist of partially digested feed materials consum ed by the animal before slaughter, t o g e t h e r with r u m e n microorganisms susp e n d e d in liquid. T h e solid p o r t i o n of RC c a n n o t be handl ed in municipal sewage t r e a t m e n t systems, and t hus creates a disposal probl em for abattoirs. At present, RC are of t e n spread as m a n u r e on crop land. If RC were a suitable feedstuff for livestock, it would alleviate t he waste disposal problem and also reduce th e cost o f feed. Ensiling agricultural p r o d u c t s a nd forage crops is a widespread practice. Ensiling has been e x t e n d e d to conserve p r o t e i n - r i c h materials such as fish a n d o t h e r an imal b y - pr oduct s which would otherwise be wasted ( S u m n e r , 1976; Disney et al., 1977; Disney, 1979). Ensiling seems to be a feasible way of preserving RC. Alo m ar (1979) successfully ensiled RC with barley or molasses at 1Present address: By-products Laboratory, Central Leather Research Institute, Adyar, Madras 600 020, India.
0377-8401/87/$03.50
© 1987 Elsevier Science Publishers B.V.
68
TABLE I Compositionof ensilingmixtures of ruminal contents (RC) and blood with wheat straw Treatment
Proportions (w/w) RC:Blood
1 2 3 4 5 6 7 8 9 10
Wheat
Dry
straw
molasses a
70 (2:1) 70 (2:1) 70 (1:1) 70 (1:1)
30 30 30 30
60 60 60 60 50 50
40 40 40 40 50 50
+ + +
(2:1) (2:1) (I:I) (I:I) (2:1) (2:1)
-+ -+ --
11
50 (1:1)
50
12
50 (1:1)
50
+
-
13 14
40 (2:1) 40 (2:1)
60 60
+ -
15 16
40 (1:1) 40 (1:1)
60 60
+ --
aPlus sign indicates 50 g dry molasses added per 1000 g mixture. 60% dry m a t t e r levels. C h i t t e n d e n (1972) reported successful ensiling of RC and ground maize stalks a n d their utilization as cattle feed. A n t h o n y (1970) demonstrated the value of fresh animal manure a n d ground grass hay in the ratio 57:43 as a feed for r u m i n a n t s . In the present study, RC, whole blood and wheat straw were ensiled in various proportions, with and w i t h o u t molasses, to examine the ensiling characteristics of the mixtures. MATERIALS AND METHODS
T h e rumen contents a n d blood were collected immediately after slaughtering beef cattle at an abattoir (Timberville, Virginia, U.S.A.). T h e dried wheat straw was ground into lengths of 2-4 cm for ease of compaction during the ensiling process. T h e rumen contents and blood, in the ratios 2:1 a n d 1:1 ( w / w ) , were mixed with various proportions of ground wheat straw with and w i t h o u t (5% w / w ) dry molasses. F i f t y grams of dry molasses was added to 1000 g of a mixture of RC, blood a n d w h e a t straw. There were 16 t r e a t m e n t s (Table 1) and the experiment was conducted as a 2 ><4 X 2 factorial design to study t h e interactions between treatments. Each pre-ensiled mixture was packed into a polyethylene bag which was placed inside a second bag, each bag being tied. T h e polyethylene bags were
69
TABLE II Composition of rumen contents and blood (% dry matter) Material
Dry matter
pH
Crude protein
Soluble carbo-
Lactic acid
Volatile fatty acids Acetic
hydrates
Prop -
Butyric
ionic Rumen contents Blood
18.4 24.3
5.8 7.2
16.2 90.2
3.2 0
0 0
2.4 0
1.5 0
0.8 0
stored in 4-1 cardboard containers. Six containers were packed per treatment (total 96). The approximate weight of each container was about 2 kg. The mixtures were ensiled for a minimum of 6 weeks. The weight, pH and contents of dry matter, lactic acid, soluble carbohydrates, volatile fatty acids and crude protein were determined on each mixture before and after ensiling. Nitrogen was estimated by the micro-Kjeldahl method. Dry matter was determined by placing 2-g samples in an oven at 150 °C overnight. Water extracts of the materials were prepared by homogenizing 25 g wet material with 100 ml distilled water in a blender for 2 min. The homogenate was filtered through 4 layers of cheese-cloth, and the filtrate was used for measurement ofpH, volatile fatty acids by gas chromatography (Erwin et al., 1961), lactic acid (Barker and Summerson, 1941, as modified by Pennington and Sutherland, 1956) and water soluble carbohydrate contents (Dubois et al., 1956, as adapted by Johnson et al., 1966). Upon opening the bags, final weights were taken and the silages were observed for colour, texture, odour and for any mould growth. RESULTS AND DISCUSSION
After ensiling, all silages had a desirable aroma with no mould growth. The composition of RC and whole blood is presented in Table II. The chemical compositions ofpre- and post-ensiled mixtures are shown in Tables III, IV and V. All variables were significantly different after ensiling ( P < 0.01 ). Dry matter content increased significantly ( P < 0.01 ) after ensiling (Table III). The dry matter content of the mixtures reflected the different proportions of straw. The crude protein content decreased significantly after ensiling ( P < 0.01 ). The crude protein of the ensiled mixtures reflected the proportions of ingredients. For example, the level decreased linearly as the level of straw increased ( P < 0.01). Also, crude protein was higher for mixtures with more blood ( P < 0.01 ). Nevertheless, the crude protein content of all mixtures would meet the dietary requirements of most ruminants.
70 TABLE III Chemical composition and dry matter change in pre- and post-ensiled mixtures Treatment No2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 SE
Dry matter (%)
Crude protein (%) ¢
Pre
Post b
Pre
Post b
Dry matter change after ensiling (units)
46.2 35.9 42.5 36.3 48.8 37.3 49.4 47.7 56.2 56.3 57.9 53.0 61.6 63.5 63.9 60.2
47.8 38.2 42.9 38.7 49.1 42.8 51.1 50.1 58.2 56.9 59.2 56.1 62.9 63.9 64.3 62.3
18.8 24.7 23.4 26.5 16.4 21.6 21.6 22.1 13.0 14.0 19.3 16.9 12.3 11.7 13.3 13.7
16.8 20.8 22.4 24.2 16.6 18.3 18.6 18.8 12.9 13.9 15.3 15.7 11.3 11.9 12.8 13.3
-t- 21.0 ÷ 52.0 - 0.4 -t- 53.4 - 9.8 % 128.7 -t- 20.0 -{- 35.6 + 19.7 - 5.5 -{- 9.3 -t- 44.3 ÷ 4.8 - 11.4 - 14.3 q- 16.0
0.08
0.40
8.93
aFor details of proportions of ingredients, see Table I. bMean values of 6 replications. CDry matter basis. + = increase of dry matter in g kg- 1of dry matter ensiled; - = loss of dry matter in g kg- 1of dry matter ensiled; SE = standard error.
T h e p H v a l u e s o f t h e initial m i x t u r e s r a n g e d f r o m 6.6 t o 7.2 ( T a b l e I V ) . A f t e r ensiling, p H v a l u e s w e r e 5 or less. A l t h o u g h d i f f e r e n c e s w e r e small, a d d ing 5% d r y m o l a s s e s l o w e r e d ( P < 0.01 ) t h e p H v a l u e o f t h e e n s i l e d m i x t u r e s . T h e lactic a c i d levels w e r e s i g n i f i c a n t l y i n c r e a s e d in all p o s t - e n s i l e d m i x t u r e s w h e n c o m p a r e d w i t h t h e i r c o r r e s p o n d i n g p r e - e n s i l e d m i x t u r e s ( P < 0.01) ( T a b l e I V ) . T h e lactic a c i d levels c o n f i r m e d t h a t l a c t a t e f e r m e n t a t i o n h a d o c c u r r e d in all t r e a t m e n t s . A d d i t i o n o f d r y m o l a s s e s i n c r e a s e d lactic acid c o n centration (P< 0.01). There was a significant decrease of water-soluble carb o h y d r a t e s ( P < 0.01 ) in all p o s t - e n s i l e d m i x t u r e s w h e n c o m p a r e d w i t h t h e i r c o r r e s p o n d i n g p r e - e n s i l e d m i x t u r e s ( T a b l e I V ) . T h e d e c r e a s e in w a t e r - s o l u b l e c a r b o h y d r a t e s d u r i n g ensiling also i n d i c a t e d t h a t f e r m e n t a t i o n h a d t a k e n place. T h e effect of ensiling RC and whole blood with wheat straw upon volatile f a t t y acids p r o d u c t i o n is p r e s e n t e d in T a b l e V. S u b s t a n t i a l levels ( P < 0.01 ) o f acetic acid a n d p r o p i o n i c acid w e r e o b s e r v e d in all t h e m i x t u r e s , while b u t y r i c
71 TABLE IV Ensiling parameters of mixtures of tureen contents, whole blood and wheat straw Treatment Numbera
Pre 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 SE
Water soluble carbohydrates
Lactic acid (%) b
Post c
Pre
Post c
Pre
Post ¢
4.7 4.8 4.5 5.0 4.6 4.9 4.6 4.6 4.6 4.7 4.4 4.6 4.5 4.7 4.7 4.7
7.6 3.2 7.4 2.9 7.3 4.3 6.5 2.7 5.6 2.4 6.2 2.8 6.2 2.8 5.8 1.4
2.4 1.4 1.9 1.2 2.6 1.6 1.8 1.9 2.2 1.5 2.3 1.6 2.5 2.1 5.0 6.7
2.6 4.0 3.9 3.7 1.6 0.9 0 0 0 0 0 0 0.1 0 0 0.1
6.9 6.9 10.0 5.3 5.7 2.2 6.3 6.2 4.4 2.9 6.0 4.9 4.3 1.8 3.1 1.8
pH
6.6 6.6 6.7 6.9 6.8 6.7 6.8 6.9 6.7 6.7 6.8 6.9 6.9 7.0 6.9 7.2
(%)b
0'02
0.33
0.62
aFor details of proportions of ingredients, see Table I. bDry matter basis. CMean values of 6 replications. SE = standard error. acid levels w e r e d e c r e a s e d m a r g i n a l l y ( P < 0.05). Valeric a n d i s o v a l e r i c acids were n o t d e t e c t e d . A few o f t h e i n t e r a c t i o n s w e r e s t a t i s t i c a l l y s i g n i f i c a n t ( T a b l e V I ) . H o w e v e r , it w a s o b s e r v e d t h a t t h e i n t e r a c t i o n s , in general, i n d i c a t e d d i f f e r e n c e s in m a g n i t u d e o f t h e y i e l d s for t h e v a r i o u s t r e a t m e n t c o m b i n a t i o n s , r a t h e r t h a n diff e r e n c e s in d i r e c t i o n . F o r e x a m p l e , in t h e case of lactic acid, all t r e a t m e n t c o m b i n a t i o n s g a v e a n i n c r e a s e in lactic acid a f t e r ensiling. F o r t h e v a r i a b l e p H , all t r e a t m e n t c o m b i n a t i o n s d e c r e a s e d t h e p H d u r i n g ensiling. I n general, t r e a t m e n t c o m b i n a t i o n s o f t h e o t h e r v a r i a b l e s e i t h e r all i n c r e a s e d t h e yield or all d e c r e a s e d it. I n t h e few i n s t a n c e s w h e r e a t r e a t m e n t c o m b i n a t i o n g a v e t h e y i e l d o f a v a r i a b l e in t h e o p p o s i t e direction, t h e m a g n i t u d e o f t h e yield w a s negligible. A l t h o u g h s m a l l r e s p o n s e s in e n s i l i n g c h a r a c t e r i s t i c s w e r e n o t e d f r o m a d d i n g d r y m o l a s s e s , e n s i l i n g w a s s a t i s f a c t o r y w i t h o u t it. T h e r e s u l t s i n d i c a t e t h a t g o o d - q u a l i t y silage o f a n acidic s w e e t n a t u r e , e x c e l l e n t t e x t u r e , a n d a c c e p t a b l e a r o m a , c o u l d b e o b t a i n e d if R C a n d w h o l e b l o o d ( r a t i o 2:1 or 1:1) are m i x e d
72 TABLE V Effect of ensilingrurnen contents and blood with wheat straw upon volatile fatty acid concentration~ Treatment b No.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Acetic
(%)
Pre
Post c
0.54 0.83 0.52 0.69 0.59 0.59 0.42 0.48 0.43 0.48 0.29 0.38 0.36 0.30 0.19 0
1.79 2.41 1.93 2.74 2.07 4.02 1.90 1.91 2.23 3.00 1.75 1.64 1.38 1.73 1.68 2.16
SE
Propionic (% )
Butyric (% )
Pre
Post c
Pre
Post ¢
0.23 0.47 0.21 0.51 0.40 0.53 0.15 0.35 0.24 0.43 0.11 0.10 0.04 0.03 0.03 0.06
0.13 0.25 0.12 0.16 0.12 0.13 0 0.12 0.11 0.14 0 0.06 0 0 0.03 0
0.05 0.15 0.02 0.12 0.12 0.02 0.01 0.01 0 0 0 0 0 0 0 0
0.32 0.47 0.19 0.25 0.20 0.32 0 0.15 0.11 0.14 0 0.09 0 0 0.14 0
0.16
0.05
0.03
aDry matter basis. bFor details of proportions of ingredients, see Table I. CMean values of 6 replications. SE = standard error.
TABLE VI Significant interactions No.
Parameter
Significant interactions~
Treatment combinations showing good ensilage
1 2 3
Dry matter Crude protein Soluble carbohydrates Lactic acid pH Acetic acid Propionic acid Butyric acid
AB, AC, BC, ABC AB, AC
60:40/2:1/50:50/2:1/_.
AB ABC AB, AC, ABC AB, BC, ABC AB, AC AC
70:30/1:1/-t60:40/1:1/+ 40:60/1:1/60:40/2:1/50:50/2:1/50:50/2:1/-
4 5 6 7 8
~A--tureen contents and blood vs. wheat straw levels, 70:30, 60:40, 50:50, 40:60; B--rumen contents vs. blood levels, 2:1, 1:1; C = molasses levels present ( + ), absent ( - ).
73 with wheat straw in the ratio 70:30, 60:40 or 50:50 at a dry m a t t e r level of 35-56%. In India, about 50 million sheep and 2 million cattle are slaughtered per annum. Approximately 4000-5000 tons of crude protein could be obtained from the RC of these animals, if it was properly collected and processed. T h e present results also indicate t h a t ensiling is the best m e t h o d of preserving RC and blood, a n d ensiled mixtures could be further investigated in feeding trials. In India, about 65-70% of animals are slaughtered in rural areas. Ensiling is a rural technology a n d hence it is particularly suitable for conservation of RC and blood from small abattoirs where only a few animals are slaughtered per day. ACKNOWLEDGEMENTS The authors express their t h a n k s to colleagues of the D e p a r t m e n t of Animal Sciences for their help and cooperation. N.M. Rao t h a n k s the Food and Agriculture Organisation of the U n i t e d Nations for awarding a fellowship on animal by-products processing. N.M. Rao is also grateful to Ms. L a k s h m i Rangachari for statistical interpretation of the results.
REFERENCES Alomar, C.D., 1979. Chemicalevaluationofensiled rumen contents. Inst. Prod. Anim.Univ.Aust. de Chile Casilla 567, Valdivia Chile, Agronom. Surv. 7(2): 89 (cited in Chem. Abstr., 1980, 92(9) 145253. Anthony, W.B., 1970. Feedingvalue of cattle manure for cattle. J. Anim, Sci., 30: 274-277. Barker, S.B. and Summerson, W.H., 1941. The colorimetric determination of lactic acid in biological material. J. Biol. Chem., 138: 535-554. Chittenden, J.A., 1972. Solid wastes in the meat packing industry. Iowa Beef Processors, Dakota City, NE. Cited by Jack L. Witherowin the National Provisioner, 26 October 1974, p. 16. Disney, J.G., 1979. Prospectus for fish silage in Malaysia, Sri Lanka, Bangladeshand the Philippines. Indo. Pac. Fish Comm. Occ. Pap. No. 1/1979, FAO/IPFC, Bangkok,p. 51. Disney, J.G., Tatterson, I.N. and Olley,J., 1977. Recent developmentsin fish silage. Proc. Cenf. Handl. Process Mark. Trop. Fish, pp. 231-240. Dubois, M.K., Gilles,A., Hamilton, J.K., Rebers, P.A. and Smith, F., 1956. Colorimetricmethod for determination of sugars and related substances. Anal. Chem., 28: 350-356. Erwin, E.S., Marco, G.J. and Emery, E.M., 1961. Volatile fatty acid analysis of blood and tureen fluid by gas chromatography.J. Dairy Sci., 44: 1768-1771. Johnson, R.R., Balwani,T.L., Johnson, L.J., McClure,K.E. and Dehority, B.A., 1966. Corn plant maturity. II. Effecton in-vitro cellulosedigestibilityand solublecarbohydratecontent. J. Anita. Sci., 25: 617-623. Pennington, R.J. and Sutherland, T.M., 1956. Ketone-bodyproduction from various substances by sheep-rumen epithelium.Biochem.J., 63: 353-361. Sumner, J., 1976. A feasibilitystudy for fish silageproduction in the IPFC region. Rep. Indo. Pac. Comm. Work. Party Fish Technol. Mark., Sri Lanka, October 1976. No. FT/76/4, Rome FAO and IPFC. Trop. Sci., 21: 221-229.
67
E n s i l i n g of R u m e n Contents and Blood with Wheat Straw N. MURALIDHARA RAO1and J.P. FONTENOT Department of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (U.S.A.) (Received 14 March 1986; accepted for publication 22 January 1987)
ABSTRACT
Rao, N.M. and Fontenot, J.P., 1987. Ensiling of rumen contents and blood with wheat straw, Anita. Feed Sci. Technol, 18: 67-73. Rumen contents and whole blood in the ratios 2:1 and 1:1 (w/w) were mixed with ground wheat straw in the proportions of 70:30, 60:40, 50:50 and 40:60 (w/w) with and without dry molasses (5% w/w). The mixtures were ensiled for 6 weeks in polyethylene bags. Weight, pH, dry matter, lactic acid, soluble carbohydrates, volatile fatty acids and crude protein were determined before and after ensiling. All silages had desirable aromas after 6 weeks fermentation, pH was between 4 and 5, and lactic acid and acetic acid levels were sufficient to ensure preservation in most of the ensiled mixtures.
INTRODUCTION R u m e n c o n t e n t s ( R C ) consist of partially digested feed materials consum ed by the animal before slaughter, t o g e t h e r with r u m e n microorganisms susp e n d e d in liquid. T h e solid p o r t i o n of RC c a n n o t be handl ed in municipal sewage t r e a t m e n t systems, and t hus creates a disposal probl em for abattoirs. At present, RC are of t e n spread as m a n u r e on crop land. If RC were a suitable feedstuff for livestock, it would alleviate t he waste disposal problem and also reduce th e cost o f feed. Ensiling agricultural p r o d u c t s a nd forage crops is a widespread practice. Ensiling has been e x t e n d e d to conserve p r o t e i n - r i c h materials such as fish a n d o t h e r an imal b y - pr oduct s which would otherwise be wasted ( S u m n e r , 1976; Disney et al., 1977; Disney, 1979). Ensiling seems to be a feasible way of preserving RC. Alo m ar (1979) successfully ensiled RC with barley or molasses at 1Present address: By-products Laboratory, Central Leather Research Institute, Adyar, Madras 600 020, India.
0377-8401/87/$03.50
© 1987 Elsevier Science Publishers B.V.
68
TABLE I Compositionof ensilingmixtures of ruminal contents (RC) and blood with wheat straw Treatment
Proportions (w/w) RC:Blood
1 2 3 4 5 6 7 8 9 10
Wheat
Dry
straw
molasses a
70 (2:1) 70 (2:1) 70 (1:1) 70 (1:1)
30 30 30 30
60 60 60 60 50 50
40 40 40 40 50 50
+ + +
(2:1) (2:1) (I:I) (I:I) (2:1) (2:1)
-+ -+ --
11
50 (1:1)
50
12
50 (1:1)
50
+
-
13 14
40 (2:1) 40 (2:1)
60 60
+ -
15 16
40 (1:1) 40 (1:1)
60 60
+ --
aPlus sign indicates 50 g dry molasses added per 1000 g mixture. 60% dry m a t t e r levels. C h i t t e n d e n (1972) reported successful ensiling of RC and ground maize stalks a n d their utilization as cattle feed. A n t h o n y (1970) demonstrated the value of fresh animal manure a n d ground grass hay in the ratio 57:43 as a feed for r u m i n a n t s . In the present study, RC, whole blood and wheat straw were ensiled in various proportions, with and w i t h o u t molasses, to examine the ensiling characteristics of the mixtures. MATERIALS AND METHODS
T h e rumen contents a n d blood were collected immediately after slaughtering beef cattle at an abattoir (Timberville, Virginia, U.S.A.). T h e dried wheat straw was ground into lengths of 2-4 cm for ease of compaction during the ensiling process. T h e rumen contents and blood, in the ratios 2:1 a n d 1:1 ( w / w ) , were mixed with various proportions of ground wheat straw with and w i t h o u t (5% w / w ) dry molasses. F i f t y grams of dry molasses was added to 1000 g of a mixture of RC, blood a n d w h e a t straw. There were 16 t r e a t m e n t s (Table 1) and the experiment was conducted as a 2 ><4 X 2 factorial design to study t h e interactions between treatments. Each pre-ensiled mixture was packed into a polyethylene bag which was placed inside a second bag, each bag being tied. T h e polyethylene bags were
69
TABLE II Composition of rumen contents and blood (% dry matter) Material
Dry matter
pH
Crude protein
Soluble carbo-
Lactic acid
Volatile fatty acids Acetic
hydrates
Prop -
Butyric
ionic Rumen contents Blood
18.4 24.3
5.8 7.2
16.2 90.2
3.2 0
0 0
2.4 0
1.5 0
0.8 0
stored in 4-1 cardboard containers. Six containers were packed per treatment (total 96). The approximate weight of each container was about 2 kg. The mixtures were ensiled for a minimum of 6 weeks. The weight, pH and contents of dry matter, lactic acid, soluble carbohydrates, volatile fatty acids and crude protein were determined on each mixture before and after ensiling. Nitrogen was estimated by the micro-Kjeldahl method. Dry matter was determined by placing 2-g samples in an oven at 150 °C overnight. Water extracts of the materials were prepared by homogenizing 25 g wet material with 100 ml distilled water in a blender for 2 min. The homogenate was filtered through 4 layers of cheese-cloth, and the filtrate was used for measurement ofpH, volatile fatty acids by gas chromatography (Erwin et al., 1961), lactic acid (Barker and Summerson, 1941, as modified by Pennington and Sutherland, 1956) and water soluble carbohydrate contents (Dubois et al., 1956, as adapted by Johnson et al., 1966). Upon opening the bags, final weights were taken and the silages were observed for colour, texture, odour and for any mould growth. RESULTS AND DISCUSSION
After ensiling, all silages had a desirable aroma with no mould growth. The composition of RC and whole blood is presented in Table II. The chemical compositions ofpre- and post-ensiled mixtures are shown in Tables III, IV and V. All variables were significantly different after ensiling ( P < 0.01 ). Dry matter content increased significantly ( P < 0.01 ) after ensiling (Table III). The dry matter content of the mixtures reflected the different proportions of straw. The crude protein content decreased significantly after ensiling ( P < 0.01 ). The crude protein of the ensiled mixtures reflected the proportions of ingredients. For example, the level decreased linearly as the level of straw increased ( P < 0.01). Also, crude protein was higher for mixtures with more blood ( P < 0.01 ). Nevertheless, the crude protein content of all mixtures would meet the dietary requirements of most ruminants.
70 TABLE III Chemical composition and dry matter change in pre- and post-ensiled mixtures Treatment No2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 SE
Dry matter (%)
Crude protein (%) ¢
Pre
Post b
Pre
Post b
Dry matter change after ensiling (units)
46.2 35.9 42.5 36.3 48.8 37.3 49.4 47.7 56.2 56.3 57.9 53.0 61.6 63.5 63.9 60.2
47.8 38.2 42.9 38.7 49.1 42.8 51.1 50.1 58.2 56.9 59.2 56.1 62.9 63.9 64.3 62.3
18.8 24.7 23.4 26.5 16.4 21.6 21.6 22.1 13.0 14.0 19.3 16.9 12.3 11.7 13.3 13.7
16.8 20.8 22.4 24.2 16.6 18.3 18.6 18.8 12.9 13.9 15.3 15.7 11.3 11.9 12.8 13.3
-t- 21.0 ÷ 52.0 - 0.4 -t- 53.4 - 9.8 % 128.7 -t- 20.0 -{- 35.6 + 19.7 - 5.5 -{- 9.3 -t- 44.3 ÷ 4.8 - 11.4 - 14.3 q- 16.0
0.08
0.40
8.93
aFor details of proportions of ingredients, see Table I. bMean values of 6 replications. CDry matter basis. + = increase of dry matter in g kg- 1of dry matter ensiled; - = loss of dry matter in g kg- 1of dry matter ensiled; SE = standard error.
T h e p H v a l u e s o f t h e initial m i x t u r e s r a n g e d f r o m 6.6 t o 7.2 ( T a b l e I V ) . A f t e r ensiling, p H v a l u e s w e r e 5 or less. A l t h o u g h d i f f e r e n c e s w e r e small, a d d ing 5% d r y m o l a s s e s l o w e r e d ( P < 0.01 ) t h e p H v a l u e o f t h e e n s i l e d m i x t u r e s . T h e lactic a c i d levels w e r e s i g n i f i c a n t l y i n c r e a s e d in all p o s t - e n s i l e d m i x t u r e s w h e n c o m p a r e d w i t h t h e i r c o r r e s p o n d i n g p r e - e n s i l e d m i x t u r e s ( P < 0.01) ( T a b l e I V ) . T h e lactic a c i d levels c o n f i r m e d t h a t l a c t a t e f e r m e n t a t i o n h a d o c c u r r e d in all t r e a t m e n t s . A d d i t i o n o f d r y m o l a s s e s i n c r e a s e d lactic acid c o n centration (P< 0.01). There was a significant decrease of water-soluble carb o h y d r a t e s ( P < 0.01 ) in all p o s t - e n s i l e d m i x t u r e s w h e n c o m p a r e d w i t h t h e i r c o r r e s p o n d i n g p r e - e n s i l e d m i x t u r e s ( T a b l e I V ) . T h e d e c r e a s e in w a t e r - s o l u b l e c a r b o h y d r a t e s d u r i n g ensiling also i n d i c a t e d t h a t f e r m e n t a t i o n h a d t a k e n place. T h e effect of ensiling RC and whole blood with wheat straw upon volatile f a t t y acids p r o d u c t i o n is p r e s e n t e d in T a b l e V. S u b s t a n t i a l levels ( P < 0.01 ) o f acetic acid a n d p r o p i o n i c acid w e r e o b s e r v e d in all t h e m i x t u r e s , while b u t y r i c
71 TABLE IV Ensiling parameters of mixtures of tureen contents, whole blood and wheat straw Treatment Numbera
Pre 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 SE
Water soluble carbohydrates
Lactic acid (%) b
Post c
Pre
Post c
Pre
Post ¢
4.7 4.8 4.5 5.0 4.6 4.9 4.6 4.6 4.6 4.7 4.4 4.6 4.5 4.7 4.7 4.7
7.6 3.2 7.4 2.9 7.3 4.3 6.5 2.7 5.6 2.4 6.2 2.8 6.2 2.8 5.8 1.4
2.4 1.4 1.9 1.2 2.6 1.6 1.8 1.9 2.2 1.5 2.3 1.6 2.5 2.1 5.0 6.7
2.6 4.0 3.9 3.7 1.6 0.9 0 0 0 0 0 0 0.1 0 0 0.1
6.9 6.9 10.0 5.3 5.7 2.2 6.3 6.2 4.4 2.9 6.0 4.9 4.3 1.8 3.1 1.8
pH
6.6 6.6 6.7 6.9 6.8 6.7 6.8 6.9 6.7 6.7 6.8 6.9 6.9 7.0 6.9 7.2
(%)b
0'02
0.33
0.62
aFor details of proportions of ingredients, see Table I. bDry matter basis. CMean values of 6 replications. SE = standard error. acid levels w e r e d e c r e a s e d m a r g i n a l l y ( P < 0.05). Valeric a n d i s o v a l e r i c acids were n o t d e t e c t e d . A few o f t h e i n t e r a c t i o n s w e r e s t a t i s t i c a l l y s i g n i f i c a n t ( T a b l e V I ) . H o w e v e r , it w a s o b s e r v e d t h a t t h e i n t e r a c t i o n s , in general, i n d i c a t e d d i f f e r e n c e s in m a g n i t u d e o f t h e y i e l d s for t h e v a r i o u s t r e a t m e n t c o m b i n a t i o n s , r a t h e r t h a n diff e r e n c e s in d i r e c t i o n . F o r e x a m p l e , in t h e case of lactic acid, all t r e a t m e n t c o m b i n a t i o n s g a v e a n i n c r e a s e in lactic acid a f t e r ensiling. F o r t h e v a r i a b l e p H , all t r e a t m e n t c o m b i n a t i o n s d e c r e a s e d t h e p H d u r i n g ensiling. I n general, t r e a t m e n t c o m b i n a t i o n s o f t h e o t h e r v a r i a b l e s e i t h e r all i n c r e a s e d t h e yield or all d e c r e a s e d it. I n t h e few i n s t a n c e s w h e r e a t r e a t m e n t c o m b i n a t i o n g a v e t h e y i e l d o f a v a r i a b l e in t h e o p p o s i t e direction, t h e m a g n i t u d e o f t h e yield w a s negligible. A l t h o u g h s m a l l r e s p o n s e s in e n s i l i n g c h a r a c t e r i s t i c s w e r e n o t e d f r o m a d d i n g d r y m o l a s s e s , e n s i l i n g w a s s a t i s f a c t o r y w i t h o u t it. T h e r e s u l t s i n d i c a t e t h a t g o o d - q u a l i t y silage o f a n acidic s w e e t n a t u r e , e x c e l l e n t t e x t u r e , a n d a c c e p t a b l e a r o m a , c o u l d b e o b t a i n e d if R C a n d w h o l e b l o o d ( r a t i o 2:1 or 1:1) are m i x e d
72 TABLE V Effect of ensilingrurnen contents and blood with wheat straw upon volatile fatty acid concentration~ Treatment b No.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Acetic
(%)
Pre
Post c
0.54 0.83 0.52 0.69 0.59 0.59 0.42 0.48 0.43 0.48 0.29 0.38 0.36 0.30 0.19 0
1.79 2.41 1.93 2.74 2.07 4.02 1.90 1.91 2.23 3.00 1.75 1.64 1.38 1.73 1.68 2.16
SE
Propionic (% )
Butyric (% )
Pre
Post c
Pre
Post ¢
0.23 0.47 0.21 0.51 0.40 0.53 0.15 0.35 0.24 0.43 0.11 0.10 0.04 0.03 0.03 0.06
0.13 0.25 0.12 0.16 0.12 0.13 0 0.12 0.11 0.14 0 0.06 0 0 0.03 0
0.05 0.15 0.02 0.12 0.12 0.02 0.01 0.01 0 0 0 0 0 0 0 0
0.32 0.47 0.19 0.25 0.20 0.32 0 0.15 0.11 0.14 0 0.09 0 0 0.14 0
0.16
0.05
0.03
aDry matter basis. bFor details of proportions of ingredients, see Table I. CMean values of 6 replications. SE = standard error.
TABLE VI Significant interactions No.
Parameter
Significant interactions~
Treatment combinations showing good ensilage
1 2 3
Dry matter Crude protein Soluble carbohydrates Lactic acid pH Acetic acid Propionic acid Butyric acid
AB, AC, BC, ABC AB, AC
60:40/2:1/50:50/2:1/_.
AB ABC AB, AC, ABC AB, BC, ABC AB, AC AC
70:30/1:1/-t60:40/1:1/+ 40:60/1:1/60:40/2:1/50:50/2:1/50:50/2:1/-
4 5 6 7 8
~A--tureen contents and blood vs. wheat straw levels, 70:30, 60:40, 50:50, 40:60; B--rumen contents vs. blood levels, 2:1, 1:1; C = molasses levels present ( + ), absent ( - ).
73 with wheat straw in the ratio 70:30, 60:40 or 50:50 at a dry m a t t e r level of 35-56%. In India, about 50 million sheep and 2 million cattle are slaughtered per annum. Approximately 4000-5000 tons of crude protein could be obtained from the RC of these animals, if it was properly collected and processed. T h e present results also indicate t h a t ensiling is the best m e t h o d of preserving RC and blood, a n d ensiled mixtures could be further investigated in feeding trials. In India, about 65-70% of animals are slaughtered in rural areas. Ensiling is a rural technology a n d hence it is particularly suitable for conservation of RC and blood from small abattoirs where only a few animals are slaughtered per day. ACKNOWLEDGEMENTS The authors express their t h a n k s to colleagues of the D e p a r t m e n t of Animal Sciences for their help and cooperation. N.M. Rao t h a n k s the Food and Agriculture Organisation of the U n i t e d Nations for awarding a fellowship on animal by-products processing. N.M. Rao is also grateful to Ms. L a k s h m i Rangachari for statistical interpretation of the results.
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