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Effect of nitrogen supplementation on the utilization of sodium hydroxide treated corn stover by dairy goats
SmaU Ruminant Research, 9 (1992) 167-171
167
© 1992 Elsevier Science Publishers B.V. All fights reserved. 0921-4488/92/$05.00
Technical Note Effect of nitrogen supplementation on the utilization of sodium hydroxide treated corn stover by dairy goats P.I. Wilke Department of Animal Science, Faculty of Agriculture, Universityof the Orange Free State, Bloemfontein, South Africa (Accepted 23 December 1991 )
ABSTRACT Wilke, P.I., 1992. Effect of nitrogen supplementation on the utilization of sodium hydroxide-treated corn stover by dairy goats. Small Rumin. Res., 9:167-171. Saanen goats, aged 14 to 18 months were used as experimental animals and housed in individual metabolism crates. Sodium hydroxide treatment of corn stover resulted in a 12% decrease in voluntary feed intake in spite of a digestibility increase of 17%. Addition of urea resulted in a 21% increase in feed intake over sodium hydroxide treated corn stover.
INTRODUCTION
Disappointing results have been obtained by farmers when using sodium hydroxide (NaOH)-treated roughages such as wheat straw and corn stover (maize straw). The main problem experienced with dairy goats was low intake of treated roughages that resulted in low overall intake of digestible energy (DE) in spite of increased digestibility that had resulted from NaOH treatment. Gihad ( 1979 ) investigated the effects of urea supplementation on intake of tropical grass by sheep. The use of a non-protein N-containing supplement lick was studied by Wilke et al. (1974) under natural pasture grazing conditions. In both cases there was a marked increase in voluntary feed intake. Availability of corn stover, especially in areas of subsistence agriculture, makes it a cheap source of roughage for goats during the non-lactating period and results in reduced feeding costs. Correspondence to."P.I. Wilke, Department of Animal Science, Faculty of Agriculture, University of the Orange Free State, P.O. Box 339, Bloemfontein, 9300, South Africa.
168
p.l. WILKE
The use of a low-cost maintenance ration consisting of NaOH-treated crop residues (corn stover without the ears) supplemented with non-protein nitrogen (urea) was investigated using Saanen goats. MATERIALS AND METHODS
Four experimental rations in the present study consisted of: (i) untreated maize straw, (ii) untreated maize straw plus urea, (iii) NaOH-treated maize straw (5% NaOH), (iv) NaOH-treated maize straw (5% NaOH) plus urea. Urea supplementation was hand-sprayed daily with a 50% water solution providing 25 g urea/kg feed. In the case of (i) and (iii), the same amount of water was applied to assure that part of the response obtained was not due to swelling of fibres. Urea supplementation increased CP content of (ii) and (iv) by about 7% units. Eight Saanen goat females, between 14-18-months old, were housed in individual metabolism crates (Fig. 1 ). The goats had an initial 20-day adaptation on the different diets in a change-over design with all animals receiving
Fig. 1. Metabolism crates in which experimental animals were kept.
EFFECT OF NITROGEN SUPPLEMENTATIONON UTILIZATIONOF TREATEDCORN STOVER
169
all diets and a change-over period of 20 days (Miller et al., 1977 ). Feeding level was 30% above refusals. RESULTS A N D D I S C U S S I O N
NaOH treatment resulted in a 12% decrease in voluntary feed intake when it was not supplemented with urea (Table 1 ). These results correspond with Miller et al. (1977) who found that the intake of untreated wheat straw was 568 g/d, untreated wheat straw plus urea 870 g/d, NaOH-treated wheat straw 429 g/d, treated wheat straw plus urea 1143 g/d. Order of response was the same, but magnitude far less (Miller et al., 1977). Alkaline treatment (2% NaOH + 2% Ca (OH) 2) of corn stover significantly increased feed intake (Oj i et al., 1977). Digestibility of maize straw was higher than wheat straw (Table 2 ). Dinius and Baumgardt (1970) found voluntary feed intake increased with higher digestibility until the feed contained about 10.5 kJ DE/g ( + 56% digestibility). Digestibility of maize straw was about 58% in this present study. The role of rumen distention decreased with increasing digestibility, and chemostatic and thermostatic factors may have controlled intake so that energy intake remained constant while DM intake decreased (Montgomery and Baumgardt, 1965 ). The increment in increased digestibility was significantly smaller in the case of maize straw than wheat straw. Hofmeyr and Jansen (1976) found that in vitro digestibility of OM (IVDOM) in maize straw increased from 6.18 to 72.5% with 5% NaOH treatment, while IVDOM of wheat straw increased from 40 to 65%. The decrease in voluntary feed intake in the case of NaOH-treated maize straw may possibly be explained by low CP content of maize straw which resulted in limited microbial activity limiting utilization of the feed (Jones, 1972; Blaxter et al., 1961 ). TABLE 1 Average dry matter intake per ks body mass Treatment
Untreated corn stover
NaOH-treated corn stover
Untreated corn stover and urea
NaOH-treated corn stover and urea
No. of animals No. of observations Average DM intake ( g / d ) SD CV% % change
8 56 441 40 9.1 0
8 56 387 98 25 - 12.3
8 56 456 62 13 3.3
8 56 482 135 28 9.3
170
P.I. WILKE
TABLE 2 Apparent digestibility of NaOH-treated corn stover with and without urea supplementation Untreated corn stover No. of animals No. of collections Apparent digestibility of GE (%) SD CV % Apparent DE content (MJ/kg) Increase in DE content (%) Apparent DE intake (M J / d ) Increase in DE intake (%)
NaOH-treated corn stover
Untreated corn stover and urea
NaOH-treated corn stover and urea
6 42
6 42
6 42
6 42
58.6 3.05 5.2
63.41 3.12 4.9
57.81 2.15 3.7
66.16 1.26 1.92
10.53
11.30
11.57
11.78
10
12
-
7
4.772
4.644
0
-2.7
4.827 -1.2
5.926 24.2
Increased rumen osmolarity may have contributed to lower intake because ruminal infusion of sodium acetate or sodium chloride by Bergen (1972) suppressed voluntary feed intake, and it was found that an osmolarity above 400 mOsm/kg led to suppressed cellulose digestion by microbes. Higher fluid content in the rumen may also have influenced intake. Warner and Stacy (1972) found that the rate of water movement through the rumen wall was a linear function of osmotic pressure in the rumen (y = 0.404 - 0.001206x; where x = m - osmol/kg). The water intake of animals receiving alkaline treated feeds shows a marked increase (Wilke et al., 1981). There was increased CP intake but the magnitude was less than obtained by Wilke et al. (1974) under grazing conditions on natural pasture. The higher feed intake obtained with CP supplementation may have been the result of increased microbial activity which in turn resulted in an increased rate of digestion and passage. Oji et al. (1977) obtained more marked increases with the treatment of maize straw with NaOH (2%) and Ca(OH)2 (2%). Digestibility of the DM increased from 51.6% to 57.9%, and voluntary feed intake by 46%. The increase in apparent digestibility during the present study (Table 2 ) was far less than in the study of Oji et al. (1977). Higher digestibility of the untreated maize straw in the present study reflects a better quality and may have influenced the response to NaOH treatment. The influence of a higher N intake is reflected in a higher DE intake partly
EFFECT OF NITROGEN SUPPLEMENTATION ON UTILIZATION OF TREATED CORN STOVER
171
due to increased feed intake and increased digestibility. Donefer et al. ( 1969 ) also found no significant increase in voluntary feed intake unless the treated material was supplemented with an N source. Increased in vitro digestibility was found by Adeleye and Kitts ( 1974 ) and Miller et al. ( 1977 ). CONCLUSIONS
Results of this study indicate that to use alkaline-treated corn stover as a maintenance diet for non-lactating dairy goats, it must be supplemented with a CP supplement.
REFERENCES Adeleye, I.O.A. and Kitts, W.D., 1974. The effect of in vitro cellulose digestion of chemically treated oat straw and poplar wood. J. Agric. Sci. Camb., 82:571-573. Bergen, W.G., 1970. Osmolality and rumen function in sheep. J. Anim. Sci., 31: 236. Blaxter, L.L., Wainman, F.W. and Wilson, R.S., 1961. The regulation of food intake by sheep. Anim. Prod., 3: 51-61. Dinius, D.A. and Baumgardt, B.R., 1970. Regulation of food intake in ruminants. 6. Influence of caloric density of pelleted rations. J. Dairy Sci., 53: 311- 316. Donefer, E., Adeleye, I.O.A. and Jones, T.A.O.C., 1969. Effect of urea supplementation on the nutritive value of sodium hydroxide treated oat straw. Am. Chem. Soc. Adv. Chem. Sci., 95: 328-339. Gihad, E.A., 1979. Intake, digestibility and nutrient utilization by sheep of sodium hydroxide treated tropical grass supplemented with soybean and urea. J. Anim. Sci., 48:1172-1176. Hofmeyer, H.S. and Jansen, T.H., 1976. The possibility of using sodium hydroxide treated roughages in animal production. S. Afr. J. Anim. Sci., 6:147-154. Jones, G.M., 1972. Chemical factors and their relations to feed intake regulation in ruminants: A review. Can. J. Anim. Sci., 52: 207-239. Miller, E.L., Johnson, T.L., Briggs, M.C.E. and Kempsey, R.G., 1977. The effect of alkali and urea on ground and pelleted all-straw diets for sheep. Proc. Nutr. Soc. Meeting. 36:129A, 12 Sept. Montgomery, M.J. and Baumgardt, B.R., 1965. Regulation of food intake in ruminants. I. Pelleted rations varying in energy concentrations. J. Dairy Sci., 48: 569-574. Oji, U.I., Mowat, D.N. and Winch, J.E., 1977. Alkali treatment of corn stover to increase nutritive value. J. Anita. Sci., 44: 789-802. Warner, A.C.I. and Stacy, B.D., 1972. Water, sodium and potassium movements across the rumen wall of sheep. Qrt. J. Exp. Physiol., 57:103-119. Wilke, P.I., Bishop, E.J.B. and Compaan, J.P., 1974. The effect of seasonal variation on the supplementation of cattle and sheep with non-protein nitrogen. Forth Hare Papers, 6: 5564. Wilke, P.I., Smith, A. and Janovsky, E., 1981. The influence of sodium hydroxide treated roughage on the water intake of dairy goats. S. Afr. J. Anim. Sci., 11: 93-98.
167
© 1992 Elsevier Science Publishers B.V. All fights reserved. 0921-4488/92/$05.00
Technical Note Effect of nitrogen supplementation on the utilization of sodium hydroxide treated corn stover by dairy goats P.I. Wilke Department of Animal Science, Faculty of Agriculture, Universityof the Orange Free State, Bloemfontein, South Africa (Accepted 23 December 1991 )
ABSTRACT Wilke, P.I., 1992. Effect of nitrogen supplementation on the utilization of sodium hydroxide-treated corn stover by dairy goats. Small Rumin. Res., 9:167-171. Saanen goats, aged 14 to 18 months were used as experimental animals and housed in individual metabolism crates. Sodium hydroxide treatment of corn stover resulted in a 12% decrease in voluntary feed intake in spite of a digestibility increase of 17%. Addition of urea resulted in a 21% increase in feed intake over sodium hydroxide treated corn stover.
INTRODUCTION
Disappointing results have been obtained by farmers when using sodium hydroxide (NaOH)-treated roughages such as wheat straw and corn stover (maize straw). The main problem experienced with dairy goats was low intake of treated roughages that resulted in low overall intake of digestible energy (DE) in spite of increased digestibility that had resulted from NaOH treatment. Gihad ( 1979 ) investigated the effects of urea supplementation on intake of tropical grass by sheep. The use of a non-protein N-containing supplement lick was studied by Wilke et al. (1974) under natural pasture grazing conditions. In both cases there was a marked increase in voluntary feed intake. Availability of corn stover, especially in areas of subsistence agriculture, makes it a cheap source of roughage for goats during the non-lactating period and results in reduced feeding costs. Correspondence to."P.I. Wilke, Department of Animal Science, Faculty of Agriculture, University of the Orange Free State, P.O. Box 339, Bloemfontein, 9300, South Africa.
168
p.l. WILKE
The use of a low-cost maintenance ration consisting of NaOH-treated crop residues (corn stover without the ears) supplemented with non-protein nitrogen (urea) was investigated using Saanen goats. MATERIALS AND METHODS
Four experimental rations in the present study consisted of: (i) untreated maize straw, (ii) untreated maize straw plus urea, (iii) NaOH-treated maize straw (5% NaOH), (iv) NaOH-treated maize straw (5% NaOH) plus urea. Urea supplementation was hand-sprayed daily with a 50% water solution providing 25 g urea/kg feed. In the case of (i) and (iii), the same amount of water was applied to assure that part of the response obtained was not due to swelling of fibres. Urea supplementation increased CP content of (ii) and (iv) by about 7% units. Eight Saanen goat females, between 14-18-months old, were housed in individual metabolism crates (Fig. 1 ). The goats had an initial 20-day adaptation on the different diets in a change-over design with all animals receiving
Fig. 1. Metabolism crates in which experimental animals were kept.
EFFECT OF NITROGEN SUPPLEMENTATIONON UTILIZATIONOF TREATEDCORN STOVER
169
all diets and a change-over period of 20 days (Miller et al., 1977 ). Feeding level was 30% above refusals. RESULTS A N D D I S C U S S I O N
NaOH treatment resulted in a 12% decrease in voluntary feed intake when it was not supplemented with urea (Table 1 ). These results correspond with Miller et al. (1977) who found that the intake of untreated wheat straw was 568 g/d, untreated wheat straw plus urea 870 g/d, NaOH-treated wheat straw 429 g/d, treated wheat straw plus urea 1143 g/d. Order of response was the same, but magnitude far less (Miller et al., 1977). Alkaline treatment (2% NaOH + 2% Ca (OH) 2) of corn stover significantly increased feed intake (Oj i et al., 1977). Digestibility of maize straw was higher than wheat straw (Table 2 ). Dinius and Baumgardt (1970) found voluntary feed intake increased with higher digestibility until the feed contained about 10.5 kJ DE/g ( + 56% digestibility). Digestibility of maize straw was about 58% in this present study. The role of rumen distention decreased with increasing digestibility, and chemostatic and thermostatic factors may have controlled intake so that energy intake remained constant while DM intake decreased (Montgomery and Baumgardt, 1965 ). The increment in increased digestibility was significantly smaller in the case of maize straw than wheat straw. Hofmeyr and Jansen (1976) found that in vitro digestibility of OM (IVDOM) in maize straw increased from 6.18 to 72.5% with 5% NaOH treatment, while IVDOM of wheat straw increased from 40 to 65%. The decrease in voluntary feed intake in the case of NaOH-treated maize straw may possibly be explained by low CP content of maize straw which resulted in limited microbial activity limiting utilization of the feed (Jones, 1972; Blaxter et al., 1961 ). TABLE 1 Average dry matter intake per ks body mass Treatment
Untreated corn stover
NaOH-treated corn stover
Untreated corn stover and urea
NaOH-treated corn stover and urea
No. of animals No. of observations Average DM intake ( g / d ) SD CV% % change
8 56 441 40 9.1 0
8 56 387 98 25 - 12.3
8 56 456 62 13 3.3
8 56 482 135 28 9.3
170
P.I. WILKE
TABLE 2 Apparent digestibility of NaOH-treated corn stover with and without urea supplementation Untreated corn stover No. of animals No. of collections Apparent digestibility of GE (%) SD CV % Apparent DE content (MJ/kg) Increase in DE content (%) Apparent DE intake (M J / d ) Increase in DE intake (%)
NaOH-treated corn stover
Untreated corn stover and urea
NaOH-treated corn stover and urea
6 42
6 42
6 42
6 42
58.6 3.05 5.2
63.41 3.12 4.9
57.81 2.15 3.7
66.16 1.26 1.92
10.53
11.30
11.57
11.78
10
12
-
7
4.772
4.644
0
-2.7
4.827 -1.2
5.926 24.2
Increased rumen osmolarity may have contributed to lower intake because ruminal infusion of sodium acetate or sodium chloride by Bergen (1972) suppressed voluntary feed intake, and it was found that an osmolarity above 400 mOsm/kg led to suppressed cellulose digestion by microbes. Higher fluid content in the rumen may also have influenced intake. Warner and Stacy (1972) found that the rate of water movement through the rumen wall was a linear function of osmotic pressure in the rumen (y = 0.404 - 0.001206x; where x = m - osmol/kg). The water intake of animals receiving alkaline treated feeds shows a marked increase (Wilke et al., 1981). There was increased CP intake but the magnitude was less than obtained by Wilke et al. (1974) under grazing conditions on natural pasture. The higher feed intake obtained with CP supplementation may have been the result of increased microbial activity which in turn resulted in an increased rate of digestion and passage. Oji et al. (1977) obtained more marked increases with the treatment of maize straw with NaOH (2%) and Ca(OH)2 (2%). Digestibility of the DM increased from 51.6% to 57.9%, and voluntary feed intake by 46%. The increase in apparent digestibility during the present study (Table 2 ) was far less than in the study of Oji et al. (1977). Higher digestibility of the untreated maize straw in the present study reflects a better quality and may have influenced the response to NaOH treatment. The influence of a higher N intake is reflected in a higher DE intake partly
EFFECT OF NITROGEN SUPPLEMENTATION ON UTILIZATION OF TREATED CORN STOVER
171
due to increased feed intake and increased digestibility. Donefer et al. ( 1969 ) also found no significant increase in voluntary feed intake unless the treated material was supplemented with an N source. Increased in vitro digestibility was found by Adeleye and Kitts ( 1974 ) and Miller et al. ( 1977 ). CONCLUSIONS
Results of this study indicate that to use alkaline-treated corn stover as a maintenance diet for non-lactating dairy goats, it must be supplemented with a CP supplement.
REFERENCES Adeleye, I.O.A. and Kitts, W.D., 1974. The effect of in vitro cellulose digestion of chemically treated oat straw and poplar wood. J. Agric. Sci. Camb., 82:571-573. Bergen, W.G., 1970. Osmolality and rumen function in sheep. J. Anim. Sci., 31: 236. Blaxter, L.L., Wainman, F.W. and Wilson, R.S., 1961. The regulation of food intake by sheep. Anim. Prod., 3: 51-61. Dinius, D.A. and Baumgardt, B.R., 1970. Regulation of food intake in ruminants. 6. Influence of caloric density of pelleted rations. J. Dairy Sci., 53: 311- 316. Donefer, E., Adeleye, I.O.A. and Jones, T.A.O.C., 1969. Effect of urea supplementation on the nutritive value of sodium hydroxide treated oat straw. Am. Chem. Soc. Adv. Chem. Sci., 95: 328-339. Gihad, E.A., 1979. Intake, digestibility and nutrient utilization by sheep of sodium hydroxide treated tropical grass supplemented with soybean and urea. J. Anim. Sci., 48:1172-1176. Hofmeyer, H.S. and Jansen, T.H., 1976. The possibility of using sodium hydroxide treated roughages in animal production. S. Afr. J. Anim. Sci., 6:147-154. Jones, G.M., 1972. Chemical factors and their relations to feed intake regulation in ruminants: A review. Can. J. Anim. Sci., 52: 207-239. Miller, E.L., Johnson, T.L., Briggs, M.C.E. and Kempsey, R.G., 1977. The effect of alkali and urea on ground and pelleted all-straw diets for sheep. Proc. Nutr. Soc. Meeting. 36:129A, 12 Sept. Montgomery, M.J. and Baumgardt, B.R., 1965. Regulation of food intake in ruminants. I. Pelleted rations varying in energy concentrations. J. Dairy Sci., 48: 569-574. Oji, U.I., Mowat, D.N. and Winch, J.E., 1977. Alkali treatment of corn stover to increase nutritive value. J. Anita. Sci., 44: 789-802. Warner, A.C.I. and Stacy, B.D., 1972. Water, sodium and potassium movements across the rumen wall of sheep. Qrt. J. Exp. Physiol., 57:103-119. Wilke, P.I., Bishop, E.J.B. and Compaan, J.P., 1974. The effect of seasonal variation on the supplementation of cattle and sheep with non-protein nitrogen. Forth Hare Papers, 6: 5564. Wilke, P.I., Smith, A. and Janovsky, E., 1981. The influence of sodium hydroxide treated roughage on the water intake of dairy goats. S. Afr. J. Anim. Sci., 11: 93-98.