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Selecting the most adequate bedding material for broiler production in Brazil
| Content Provider | Scilit |
|---|---|
| Author | Garcia, Rg Paz, Icl Almeida Caldara, Fr Naas, Ia Pereira, Df Ferreira, Vmos |
| Copyright Year | 2012 |
| Abstract | Broiler chicken production is widely dispersed across the globe, and one important issue for growers is the selection of adequate bedding material, as the availability and price of substrates varies among countries and regions within a same country. This study aimed at applying a multiple criteria analysis approach for the selection of the most appropriate bedding material for broiler production. Based on field research data and growers' experience, the most desirable characteristics of a litter material were chosen as the main criteria. The selected materials were wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum) , 50% sugar cane bagasse (Saccharum L.) plus 50% wood shavings, 50% sugar cane bagasse (Saccharum L.) plus 50% rice husks, and pure sugar cane bagasse (Saccharum L.) . The analytical hierarchy process (AHP) was applied for selecting the most suitable bedding material. Validation was performed using data from previous studies carried out in central-western Brazil on the effects of different types of bedding material on broiler carcass quality. Considering the selected criteria, several bedding materials were tested and ranked, and the results showed that wood-shavings litter was the best option (weight = 0.28), followed by rice husks (weight = 0.24). All other tested alternatives presented lower scores and were, therefore, not considered for use. The AHP approach was found to be an efficient tool to select the most appropriate litter material under specific scenarios. Keywords: Alternative bedding material, broiler production, multiple criteria analysis, AHP. INTRODUCTION Bedding material acquisition and litter management are important issues for broiler producers. The sustainability of broiler production requires bedding material to be environmentally friendly, and the replacement of litter needs to be efficient and cost-effective in order to be implemented by growers in a profitable way (Mayne et al. , 2007; Bilgili et al. , 2009). This requires the availability of alternative bedding sources, as well as good understanding of how to reduce NH 3 emissions in reused litter. Managing litter moisture is challenging in reused litter, especially during the last weeks of the growout. The important factors that influence moisture in the rearing environment include short downtimes between flocks, partial-house brooding, evaporative cooling systems, and poor drinking water management (Bilgili et al. , 2009). Health issues and the incidence of breast burns and blisters, leg abnormalities, and footpad lesions are reported in the literature as partially due to poor litter conditions (Benabdewelil & Ayach, 1996). Amongst the available multi-attribute approaches, the analytic hierarchy process (AHP) is the best because it is capable of combining different types of criteria in a multi-level decision structure in order to obtain a single score for each alternative and to rank the proposed alternatives overall. Several studies have been published on different AHP scenarios and arrays, and the conclusions support the suitability of this analysis for the selection of specific criteria (Benabdewelil & Ayach, 1996; Karami, 2006; Omkarprasad & Sushil, 2006; Halmar et al. , 2009; Almeida Paz et al. , 2010). This study aimed at applying the AHP approach for the selection of the most appropriate bedding material considering all restrictions and benefits to the producer. MATERIALS AND METHODS ApplyingAHP model involves the following steps: (a) structuring the selection problem, (b) identifying the technological options, (c) identifying the applicable criteria, (d) developing the weighting schemes, and (e) ranking the management or technological options. These steps are detailed below. Structuring the selection of the appropriate broiler bedding material and identifying the options Identifying and structuring the objective of selecting the proper broiler bedding material required careful literature investigation to provide the basis for quantitative modeling. The fundamental challenge was to identify the attributes that producers genuinely consider important because the objective hierarchies should be constructed according to this classification (Rosado Jr. et al. , 2011). In this specific study, the main goal was to select the appropriate broiler bedding material for a specific scenario. The attributes were selected based on the criteria broiler growers generally use when purchasing bedding material and on previous research results (Bowers et al. , 2003; Bilgili et al. , 2009; Macklin & Krehling, 2010). Choosing a conventional or alternative bedding material involves selecting from a set of available options, each of which may fulfill some or all of the desired criteria. Although there theoretically are several types of adequate bedding alternatives, many options are often considered to be untenable due to technical restrictions (Macklin et al. , 2005; Mayne et al. , 2007; Bilgili et al. , 2009; Garcia et al. , 2010). Identifying the applied selection criteria The selected criteria were chosen based on findings published in the current literature (Bowers et al. , 2003; Mayne et al. , 2007; Bilgili et al. , 2009; Freitas et al. , 2009) and on growers' experience and knowledge. The scheme of the system was designed using the following three distinct levels: level 1 represented the goal, level 2 represented the most important characteristic of a bedding material, and level 3 represented the related characteristics that fulfill level 2 ( Figure 1 ). Developing the weighting schemes and ranking the options The purpose of the AHP is to provide a vector of weights expressing the relative importance of the alternatives for each criterion. The adopted scale of importance was defined according to the method described by Saaty (1977), using a 1–9 score scale for pairwise comparison ( Table 1 ). When the AHP approach is applied, a pairwise comparison matrix is established. The rows and columns of this matrix represent the components that belong to the same parent component in the decision hierarchy (Eq. 1). The weight of component i compared to component j relative to the parent component is determined using Saaty's scale ( Table 1) . The weight is then assigned to the (i, j) th position of the pairwise comparison matrix (Saaty, 1980) in order to support comparisons within a limited range, but with sufficient sensitivity. The reciprocal of the assigned number is assigned to the (j, i) th position. Once the pairwise comparison matrix is established, the weights of the components are calculated by solving for the eigenvector of the pairwise comparison matrix: where w is the weight of importance and the criterion is more important than . Pairwise comparisons are then made between each pair of factors at a given level of the hierarchy relative to their contribution to the factor at the immediately preceding level. These pairwise comparisons yield a reciprocal (n, n) matrix , where a ii = 1 (diagonal elements) and a ji = 1/a ij . Suppose that only the first column of matrix is provided to state the relative importance of factors 2, 3, . . . , with respect to factor 1. If the judgments were completely consistent, then the remaining columns in the matrix would be completely determined by the transitivity of the relative importance of the factors. However, there would be no consistency except for that created by setting a ji = 1/a ij . Therefore, the comparison needs to be repeated for each column of the matrix; specifically, independent judgments must be made for each pair. is consistent if and only if λ max = . However, the inequality of λ max > always exists; therefore, the average of the remaining eigenvalues (λ) can be used as a consistency index (CI; Eq. 2), which is the difference between λ max and divided by the normalizing factor (n-1). CI = (λmax – n)/(n – 1) Eq. 2 where CI = consistency index; λ max = highest eigenvalue; and n = number of matrix elements. The CI of the studied problem is compared with the average random index (RI) obtained from associated random matrices of order n to measure the error due to inconsistency (Saaty, 1977; Saaty, 1980). A consistency ratio (CR = CI/RI) with a value ≤ 0.1 should be maintained for the matrix to be consistent; otherwise, the pairwise comparisons should be revised. The homogeneity of factors within each group, a small number of factors in the group, and a better understanding of the decision problem would improve the consistency index. Field validation The validation was performed using data obtained from a field study (Caldara et al. , 2009; Freitas et al. , 2009; Bilgili et al. , 2009; Almeida Paz et al. , 2010) comparing six different bedding materials available in most regions of Brazil, as well as mixtures of these materials such as wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum) , 50% sugarcane bagasse (Saccharum L.) plus 50% wood shavings, 50% sugarcane bagasse (Saccharum L.) plus 50% rice husks, and pure sugarcane bagasse (Saccharum L.) . The wood shavings consisted of nearly 80% of Eucaliptus saligna and 20% of other mixed woods. Chopped grass was 1 to 1.5 cm long, and sugarcane bagasse was 0.1 to 3 cm long. All tested bedding materials were applied at a depth of 10 cm. A total of 3,240 broiler chickens (Manual, 2010) were distributed in 60 pens measuring 4.5 m 2 each, each equipped with a bell drinker and a tube feeder. Flock density was 12 birds m -2 , which is typical in Brazil. House side walls were covered with curtains and inside temperature was controlled using fans and foggers. Chicks were brooded using 250 W infrared lamps, one per pen. The lighting regime was 24 h of light during the entire rearing period using 40 W lamps, which provided an average of 22 lx. All birds received feed and water ad libitum during the entire experimental period. The feeding program included the following three phases: a starter diet (day 1-21) |
| Related Links | http://www.scielo.br/pdf/rbca/v14n2/v14n2a6.pdf http://www.scielo.br/scielo.php?script=sci_pdf&pid=S1516-635X2012000200006&lng=en&nrm=iso&tlng=en |
| Ending Page | 127 |
| Page Count | 7 |
| Starting Page | 121 |
| ISSN | 1516635X |
| e-ISSN | 18069061 |
| DOI | 10.1590/s1516-635x2012000200006 |
| Journal | Brazilian Journal of Poultry Science |
| Issue Number | 2 |
| Volume Number | 14 |
| Language | English |
| Publisher | FapUNIFESP (SciELO) |
| Publisher Date | 2012-06-01 |
| Access Restriction | Open |
| Subject Keyword | Brazilian Journal of Poultry Science Agricultural Engineering |
| Content Type | Text |
| Resource Type | Article |
| Subject | Animal Science and Zoology |
