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A simple method of treating straw with alkali has recently been developed that can boost the rate of gain of growing animals and the output of adult stock substantially and cheaply. The digestibility of straw is low - only 40 - 50 per cent - and thus it does not give much energy to the animals that eat it. The alkali treatment of straw increases digestibility to 50 - 60 per cent. Animals also eat 10 - 20 per cent more of the treated straw. As a result they get much more energy (up to 50 per cent more) when straw is treated.
The method of treatment is simple and requires nothing more than a garden sprinkling can, a hay fork, a pair of rubber gloves, and a pair of goggles. The latter two are for safety, as caustic soda can burn the skin and eyes if it splashes. Care must, therefore, be taken in handling it. In case of accident, the affected area should be immediately washed with large amounts of clean water Once the alkali is sprinkled on the straw it is no longer harmful. The straw must be broken or chaffed in order to be treated uniformly and easily. The straw to be treated is piled onto a pucca floor. One man sprinkles the caustic soda solution over the straw and another man turns the pile simultaneously with the hay fork. It is important to achieve uniform wetting of the straw.
The caustic soda solution can be made from solid flakes or from a lye solution. The latter contains 50 - 60 per cent caustic soda and is less difficult to handle when making up the solution for treatment, but must be stored and transported in drums, which is not as convenient as handling caustic soda flakes in bags. Usually the cost of caustic soda (dry flakes equivalent) is less, often only half the cost, in the form of lye than in the form of flakes, and for this reason is preferred. If flakes must be used, it is advisable to make up a 50 per cent stock solution in a drum; this makes the daily preparation of the dilute solution used in treatment more convenient. For treating the straw, make up a 2 per cent (2 kg/100 I) solution of flakes, or a 4 per cent (4 kg/100 I) solution of lye. Two litres of solution are needed for each kilogramme of straw. The sprayed straw will be moist, dark yellow in colour, and have a slight smell of caustic soda. A fresh batch should be prepared every day, though it should not be fed until 24 hours after it is treated. This is because the caustic soda continues to react slowly with the straw for 24 hours. Other feeds should be mixed with the treated straw only at the time of feeding it.
In order to obtain the maximum benefit from treated straw, it should further be treated with urea. The urea should be made into a solution (1 kg/10 1) and sprinkled on the straw at the rate of 1 1/10 kg of straw just before feeding. A complete mineral mixture should also be added to the diet.
Experiments have shown that a combination of alkali and urea treatment of straw can boost the daily rate of gain in growing stock by at least 0.2 kg/day. This will be equivalent to doubling the rate of weight gain or more, which means a much earlier first calving for heifers and start of working life for bullocks.
These recommendations are for average animals. Those fed large amounts of concentrates and/or green forage may not respond to straw treatment unless the amount of alkali is increased. If straw constitutes only about half of the diet (on a dry-feed equivalent basis), it should be treated with a 4 per cent solution of caustic soda flakes or an 8 per cent solution of lye. All additional feeds should be mixed at the time of feeding. Urea treatment may be dispensed with. A mineral supplement will, however, still be desirable.
Animals given treated straw will need to drink more water than usual, and provision should be made for this.
Table 4 shows the calculation of milk-production efficiency. The data for the consumption of various feeds on untreated straw diet represent average village feeding rates and are taken from Amble et al. (20). Lactation milk yield for the untreated straw diet is estimated as the national average, as is the frequency of calving, namely, once every two years (21). Urea energy is not included in the total for energy input, on the grounds that much of it can be recovered and used as a fertilizer on crops. This procedure results in crediting the NaOH with all the improvements in productivity; thus the last three figures in the table, relating to the MJ NaOH energy per MJ milk or milk protein energy, are underestimated.
|Mature weight (kg)||400||400|
|Life span (years)||11||11|
|Age at first calving||5||35|
|Number of lactations/lifetime||3||4|
|Lactation yield (kg)||900||1,200|
|Lifetime milk production (kg)||2,700||4,800|
|Daily feed consumption (average over lifetime; kg)straw||4.5||55|
|urea, 1% straw||0.055|
|NaOH, 4% of straw||0.220|
|Lifetime milk consumption (kg)||100||100|
|Lifetime energy intake (MJ)|
|from feeds only||372,902||430,703|
|from feeds + NaOH||475,751|
|Lifetime energy output (MJ)|
For the method of calculating the ratio MJ NaOH energy/MJ output, see Annex 2. The increased production due to alkali treatment is a very rough estimate. Growth rate can be doubled, leading to a reduction in age at first calving of about 1.5 years, making it possible for an animal to have one extra lactation in its lifetime. Data from a substitution trial with milk cows (22) indicate that treated straw fed ad libitum to cows is equal to at least 0.5 kg concentrate mixture/day. This, in turn, should be equal to 1 litre of milk/day in village buffaloes on the plane of nutrition indicated in the table (23). Energy values (MJ/kg) used in calculations are as follows, assuming straw and concentrates contain 90 per cent dry matter and grass/forage contains 25 per cent.
|Protein in milk||1.0|
|NaOH (manufacturing cost)||51.0 (24)|
Assumed energy contents of carcasses (MJ) are:
|Protein in calf||150|
|Protein in buffalo||3,000|
The efficiency of a bullock with similar feed intake will be only slightly less than the buffalo in this example (untreated straw) if it works 1,200 hr/yr over a 6-year working life and has an 11-year total life span; i.e., 0.5 hp x 0.7455 kw x 1,200 hour x 6 x 3.6 MJ/kwh = 9,662 MJ energy output (2).
1. J.J. Patil, "The Gobar Gas Plant: Its Development, Present Status and Future,' paper presented to the ESCAP/NCST Seminar on Biogas Utilization and Technology, held in New Delhi 25 July to 2 August 1975.
2. A. K.N. Reddy and K. K. Prasad, "Technological Alternatives and the Indian Energy Crisis," Economic and Political Weekly. Special Number, pp. 1465 - 1502. August 1977.
3. H.R. Srinivasan, "Biogas (Gobar Gas) and Manure from the Waste of Farm Animals," paper submitted to the UNEP/FAO Seminar on Residue Management - The Management of Agricultural and Agro-Industrial Wastes, held in Rome, 18 - 21 January 1977.
4. M.G. Jackson, "Treating Straw for Animal Feeding: An Assessment of Its Technical and Economic Feasibility," FAO Animal Production and Health Paper No. 10, FAO, Rome, 1978.
5. K.C. Sen, S.C. Ray, and S.K. Talapatra, "The Nutritive Value of Alkali-Treated Cereal Straws," Indian J. Vet. Sci. 12: 263 (1942).
6. S.J. Watson, "Increasing the Feeding Value of Cereal Straws," J. Royal Agric. Soc. England 101 (Part II): 37 (1941).
7. T. Homb, "Norwegische Erfahrungen bei der strohaufschliessung nach dem Beckmanschen Verfahren," Futterkonservierung, Frankf./Main 2: 129 (1956).
8. N.D. Kehar, "Effect of Feeding Aikali-Treated Straw on the Growth of Young Cattle," Indian J. Vet. Sci. 24: 189 (1954).
9. Chandra, Suresh, and M.G. Jackson, "A Study of Various Chemical Treatments to Remove Lignin from Coarse Rough-ages and Increase Their Digestibility," J. Agric. Sci. Camb. 77: 11 (19711.
10. M. Singh and M.G. Jackson, "The Effect of Different Levels of Sodium Hydroxide Spray Treatment of Wheat Straw on Consumption and Digestibility by Cattle," J. Agric. Sci Camb. 77: 5 (1971).
11. M. Singh, M.L. Verma, M.G. Jackson, and K.V. Pitchaiah, in Improved Utilization of Agricultural Waste Materials and Industrial By-products as Livestock Feed Research Progress Report 1969 - 1974, pp. 92 - 102, G.B. Pant University, Pantnagar, India, 1975.
12. U.S. Agrawal, P.C. Sah, and R.C. Jakhmola, in Investigations on Agricultural By-products and Industrial Waste Materials for Evolving Economic Rations for Livestock. Research Progress Report 1976 - 1977, pp. 26 - 37, G.B. Pant University, Pantnagar, India, 1977.
13. J.A. Kategile, "Factors Affecting the in vivo Digestibility and the Voluntary Feed Intake of Sodium Hydroxide-Treated Maize-Cob Diets and the Performance of Heifers Fed on Sodium Hydroxide-Treated Maize-Cob-Based Diets," Ph.D. thesis, University of Dar-esSalaam, 1977.
14. A.F.E. Palmer, "An On-Farm Research System: Two Papers on Maize Research in Pakistan," Asian Report Series No. 4, International Maize and Wheat Improvement Centre, New Delhi.
15. J. Krummel and W. Dritschilo, "Resource Costs of Animal Protein Production," Wld. Anim. Rev. 21: 6 (1977).
16. U.I. Oji and D.N. Mowat, "Breakdown of Urea to Ammonia for Treating Corn Stover," Abstract Am. Anim. Sci. Soc., 1977.
17. J. Keran, E. Coxworth, H. Nicholson, and R. Chaplin, Ammoniation of Straw to Improve Its Nutritional Value as a Feed for Ruminant Animals, University of Saskatchawan Agricultural Extension Publication 329, 1977.
18. J. A. Tatchel I, The Energy Input into a Bag of Fertilizer, I Cl Agricultural Division, Birmingham (cited by K.I. Blaxter, "The Energetics of British Agriculture," J. Sci. Food Agric., 76: 1055 ).
19. K.L. Blaxter, The Energy Metabolism of Ruminants p. 169, Hutchinson, London, 1962.
20. V.N. Amble, V.V.R. Murthy, K.V. Sathe, and B.B.P.S. Goel, "Milk Production of Bovines in India and Their Feed Availability, " Indian J. Vet Sci. Anim. Husb. 35: 22 (1965).
21. Government of India, Indian Livestock Census. Ministry of Food and Agriculture, Directorate of Economics and Statistics, New Delhi, 1972.
22. K.V. Pitchaiah and M.G. Jackson, in Improved Utilization of Agricultural Waste Materials and Industrial By-products as Livestock Feed, Research Progress Report 1969 1974, pp. 102 - 108, G.B. Pant University, Pantnagar, India, 1975.
23. J.W. Meilor and B. De Ponteves, "Effect of Growth in Demand for Milk on the Demand for Concentrate Feeds: India, 1951 - 76," Indian J. Agric. Econ. 19: 131 (1964).
24. G. Leach and M. Slesser, "Energy Equivalents of Network Inputs to Food Producing Processes," report of Strathclyde University, Glasgow, 1973 - cited by E. Owen, in A. N. Duckham, J.G.W. Jones, and E.H. Roberts (eds.), Food Production and Consumption: The Efficiency of Human Food Chains and Nutrient Cycles, pp. 289 - 318, North Holland, Amsterdam, 1976.
Straw is more effectively treated with sodium hydroxide than with ammonia for increasing digestibility. However, urea would have the advantage of introducing the elements of nitrogen for protein synthesis.
It was questioned whether the financial incentive would suffice to encourage farmers to adopt straw treatment, as it takes two or three seasons for the beneficial effects of treated straw to be of evident significance. For this reason, it was recommended that straw treatment projects be run in conjunction with milk production ones, because increased milk production is a convincing indicator of improved nutrition in cows fed treated straw.
Straw treatment projects are suitable at both the village and individual farm level. It was queried whether money might not be better spent on buying groundnut meal rather than on straw treatment; it was pointed out that straw is far more plentiful than groundnut.
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