Evaluation of Various Chemical Treatments of Sawdust as a Replacement for Wheat Offal in Feeding Goat (Capra prisca)

Abstract

An animal nutrition experiment, using wheat offal control, was set-up with a view to finding the effects of various chemical treatments of sawdust on its nutritional parameters. The aim was to come-up with a sustainable new way of managing the menace of sawdust, an urban solid waste, that is becoming cumbersome to manage. Caustic soda, (NaOH); Urea, ((NH2)2CO) and Wood ash were used to treat the sawdust and thereafter supplemented with molasses. The results indicated a significant effect (P<0.05) of rations on Average Daily Gains, Feed Conversion Ratio and on Feed cost per Kg gain. It was, therefore, established that the digestibility coefficients of the treated sawdust were high enough to cause increase in live-weight of the test animals and that the poor nutritional values preventing the use of sawdust as animal feed in poor nations can be enhanced by treating it with Urea, Caustic soda and/or Wood ash.

Headnote

Abstract: An animal nutrition experiment, using wheat offal control, was set-up with a view to finding the effects of various chemical treatments of sawdust on its nutritional parameters. The aim was to come-up with a sustainable new way of managing the menace of sawdust, an urban solid waste, that is becoming cumbersome to manage. Caustic soda, (NaOH); Urea, ([NH^sub 2^]^sub 2^CO) and Wood ash were used to treat the sawdust and thereafter supplemented with molasses. The results indicated a significant effect (P<0.05) of rations on Average Daily Gains, Feed Conversion Ratio and on Feed cost per Kg gain. Feed costs per Kg gain were better for the Urea and Caustic soda treated sawdust rations compared to the control. There was, however, no significant effect on Final weight and on Feed intake. It was, therefore, established that the digestibility coefficients of the treated sawdust were high enough to cause increase in live-weight of the test animals and that the poor nutritional values preventing the use of sawdust as animal feed in poor nations can be enhanced by treating it with Urea, Caustic soda and/or Wood ash.

Keywords: Sawdust, Urban solid waste, Waste Management, Potential Livestock Feed.

1. Introduction:

Sawdust, a by-product of sawmilling industries, is produced in very large quantities in most developing nations, consequent to the ever rising demand for furniture and building materials. Agbim and Omaliko, (1993) observed that the accumulation of this waste, and its attendant environmental hazard are of great concern. A general attribute of this and other wastes, is the large quantity generated and the high costs of effective disposal, especially if long hauls are undertaken. For most sawmilling industries, the best and most popular means of disposing sawdust is by open-air burning, although a little percentage is used as fuel, poultry litter and other purposes (Ebhodage, 1993).

Studies in the management of sawdust as waste are not new in Nigeria, but most of these studies have had their focus on utilizing the waste as a soil amendment material, with promising results. For example, Allison, (1993); Mbagwu, (1995 and 1996); Ebhodaghe, (1993) and Ibrahim, (1994) had obtained favorable results indicating the high potentials of sawdust in increasing the fertility status of tropical soils by improving their organic matter contents, thus, bringing about increase in yields, with less corresponding costs of inputs. Ibrahim, (2001) had attempted a study on exploring the potentials of sawdust as a livestock feed, and the results have been encouraging.

Theoretical Assumptions

The basic theoretical assumptions upon which this work is based are

i. Given that:

* Crop-Residue-Urea, popularly referred to as CRU-Process in which dried cornstalks are sprinkled with 0.5% - 1.5% urea solution and buried for 3weeks, during which the fibrous stalks are softened, thereby becoming more nutritious (in terms of proteins, especially Non- Protein-Nitrogen [NPN]) and more relished by ruminants.

* Urea has an unpalatable taste as feed for livestock, but the addition of molasses to such unpalatable feeds has been found to increase the palatability as well as the energy and mineral contents, such that when fed along with CRU-process product at between 3% - 10% levels, it increases the palatability and the nutritional values of the urea-treated cornstalks.

ii. It is assumed that:

* Sawdust, which is more fibrous than cornstalks, may also be softened and have its nutritional values improved by a similar process of urea treatment especially if a stronger urea solution and longer incubation period is employed.

* Similarly, the use of other chemicals such as sodium hydroxide (NaOH) or wood-ash in the treatment may produce similar improvements in nutritional values so that the product could serve as feed for livestock.

* It is also assumed that the addition of a higher level of molasses to the treated sawdust may enhance its voluntary acceptability as well as its feeding value for livestock.

2. Materials and Methods:

Materials: A composite of sawdust was obtained locally from a timber saw-mill in Katsina. Caustic soda was purchased from a chemical laboratory retail shop and the wood ash sourced from cooking spot employing firewood as fuel. Blackstrap type of molasses and wheat offal of Savannah Sugar Company, Numan and Honeywell, Lagos respectively were purchased from a local Veterinary shop.

Chemical Treatments:

i. Caustic Soda Treatment: A 2% (1.25moles/dm3) caustic soda solution was sprinkled on the sawdust at the rate of 1liter/kg. It was then air-dried under shade for 7days to make it crisp dry and prevent fungal growth while in storage. The dried caustic soda-treated sawdust was further mixed with molasses at a ratio of 1:9 (molasses: sawdust) as described by Ibrahim (2005). This was designated CM-S.

ii. Urea Treatment: A 2% (3.33moles/dm3) urea solution was sprinkled on the sawdust at the rate of 1liter/kg. The moist sawdust was then stacked, sealed in airtight polythene and buried in a pre-constructed pit of 2m3 for 30days. Thereafter, it was removed and dried (under shade) to disperse free ammonia. The resultant compound was then mixed with molasses at a ratio of 1:9 (molasses: sawdust) and designated UM-S.

iii. Wood Ash Treatment: The sawdust was soaked in clean ordinary water for 1hour at the rate of 1Kg/liter and then sprinkled with wood ash at the rate of 0.2Kg/Kg sawdust, stacked, sealed and buried in a pre-constructed pit for 30days. The anaerobically fermented sawdust was afterwards dried to disperse poisonous gasses and prevent fungal growth and treated with molasses as done in caustic soda and urea treatments. It was designated WM-S.

iv. Wheat Offal Treatment: Wheat offal treated with molasses at a ratio of 1:9 (molasses: wheat offal) and designated WO-M. It serves as the control.

These 4 diets were offered to 4 groups of 5 yearling goats at the rate of 1.2Kg/head/day. In addition, each animal was offered a basal diet of 0.5Kg groundnut haulms plus free choice mineral salt-lick and water. The 20 goats weighed approximately 10.00Kg each. Hence, there were 4 dietary treatments and 5 goats per treatment, with each goat serving as a replicate. All the animals were de-wormed with Albindazole® prior to the commencement of the 10-week experiment.

Completely randomized experimental design, as outlined by Steel and Torrie, (1980) was used in the feeding trial and the following data were collected from each replicate animal: feed intake; weight gain; feed conversion ratio and feed cost in Nigerian Naira, NGN/Kg weight gain.

Percentage dry matter digestibility (digestibility coefficient) was determined through Ranjhan, (1990) method:

Digestibility coefficient = Feed digested (Kg)/Feed consumed (Kg) x 100.

Where Feed digested = Feed not recovered in feces (assimilated/absorbed in the GIT).

Feed consumed = Total feed ingested.

Data collected were summarized and subjected to analyses of variance (ANOVA) using statistical analysis system (SAS©, 1988). Differences between treatment means, where ANOVA was significant were compared using Duncan's New Multiple Range Test as described by Gomez and Gomez, (1984) and Obi, (1986).

Costs of materials were based on the prevailing market prices.

3. Results and Discussions:

Table 1 indicates the results of the performance of the animals fed molasses-treated wheat offal, WO- M as the control and the variously treated sawdust as a replacement for the WO-M.

Table 1 shows that there were no significant effect of diets (P>0.05) on the final weight and feed intake. There was however, a significant difference in Average Daily Gain, ADG between WO-M, CM-S and WMS diets (P>0.05). There was no significant difference observed for ADG between UM- S and WO-M diets. The WM-S diet had significantly lowest value for ADG of 53.10g/head (P<0.05). There were significant difference between treatment means for Feed Conversion Ratios, FCR as a result of dietary treatments (P>0.05). WO-M and UM-S had the best FCR (11.13 and 11.97 respectively). CM-S had only a slight improvement on FCR above the values obtained for WM-S. Feed Cost (NGN/Kg gain) was significantly affected by dietary treatments (P>0.05). Treated sawdust rations had lower feed cost per Kg gain than the wheat offal-based control diet, WO-M. Urea-treated sawdust, UM-S as well as Wood ash- treated sawdust, WM-S resulted in significantly lower feed cost per Kg gain than the CM-S and WO-M diets (P>0.05).

4. Conclusion:

The results obtained from this work indicated significant effect of rations on ADG, FCR and Feed cost (NGN/Kg gain). There were however, no significant effects on Final weight and Feed intake. The improvements observed on ADG and on FCR for WO-M, UM-S and CM-S rations might have been as a result of the higher percentage digestibility observed for these rations.

Despite the similarities in FCR for WO-M, CM-S and UM-S rations, Feed cost per Kg gain was better for UM-S and CM-S rations than for WO-M. The high cost for WO-M ration appears to be due to the much higher cost for wheat offal compared to the almost totally free cost for sawdust.

This work has established that poor nutritional values of sawdust for use as animal feed can be enhanced by treating it with Urea, Caustic soda and Wood ash and that the treated compounds were voluntarily accepted by goats, Capra prisca. The digestibility coefficients of the rations were high enough to cause increase in live-weight of the test animals.

As is the case with all new areas of research, the horizon of effective utilization of sawdust in the livestock industry very wide, a new door has just open.

References

References

[1] F.E. Allison, Soil Organic Matter and its Role Crop Production, Elsevier Scientific Publishing, London, 1993.

[2] G.D. Steel and J.H. Torrie, Principles and Procedures of Statistics: A Biometrical Approach (2nd Edition), McGraw-Hill Book Company, Inc, New York, 1980.

[3] I.U. Obi, Statistical Methods of Detecting Differences between Treatments Means, Snapp Press, Enugu, Nigeria, 1986.

[4] J.S.C. Mbagwu, Sub-soil productivity of an Ultisol in Nigeria as affected by organic waste and in-organic fertilizer amendments, Soil Science, 140(1995), 436-444.

[5] J.S.C. Mbagwu, Effects of organic amendments on some physical properties of a tropical Ultisol, Biological Wastes, 28(1996), 257-267.

[6] K.A. Gomez and A. Gomez, Statistical Procedures for Agricultural Research, John Wiley and Sons, New York, 1984.

[7] M.Y.E. Ibrahim, Laboratory studies on sawdust and its potentials as a livestock feed, BIJE, 4(1) (December) (2003), 1-9.

[8] M.Y.E. Ibrahim, Feeding and growth response of weaner rabbits on molasses supplemented diet, BIJE, 5(1) (2005), 113-119.

[9] N.N. Agbim and C.F.E. Omaliko, Forage-corn response to rice-mill waste and fertilizer, Journ. Environ. Qual., 12(3) (1993), 320-324.

[10] P.O. Ebhodaghe, Conditioning of sawdust as a suitable soil amendment for plant growth, Un- published M.Sc. Thesis, Department of Soil Science, University of Nigeria, Nsukka, (1993).

[11] SAS, Institute Inc, SAS/STAT Guide for Personal Computer, Version 6, Edit Cary, NC, USA, 1988.

[12] S.K. Ranjhan, Animal Nutrition in the Tropics, Vikas Publishing House, Pvt. Ltd., Sahibabad Distt., Ghaziabad, UP, India, 1990.

[13] Y.E. Ibrahim, Effects of raw, fermented and vermicomposted poultry droppings on some soil characteristics and the growth and response of Solanum melongena L., KJPAS, 2(1-2) (2009), 97-100.