Tackling the future challenges of Organic Animal Husbandry - vTI
Tackling the future challenges of Organic Animal Husbandry - vTI
Tackling the future challenges of Organic Animal Husbandry - vTI
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RAHMANN G & GODINHO D (Ed.) (2012): <strong>Tackling</strong> <strong>the</strong> Future Challenges <strong>of</strong> <strong>Organic</strong> <strong>Animal</strong> <strong>Husbandry</strong>.<br />
Proceedings <strong>of</strong> <strong>the</strong> 2 nd OAHC, Hamburg/Trenthorst, Germany, Sep 12-14, 2012<br />
Route optimization s<strong>of</strong>tware is widely used within o<strong>the</strong>r parts <strong>of</strong> <strong>the</strong> transport sector, but <strong>the</strong>re have<br />
only been a handful <strong>of</strong> studies on slaughter transports and <strong>the</strong>se have used relatively small datasets<br />
(Ljungberg et al. 2007, Oppen & Løkketangen 2008, Oppen, et al. 2010).<br />
We test <strong>the</strong> efficacy <strong>of</strong> three different route optimization methods, <strong>the</strong> Clarke & Wright heuristic<br />
(C.W), drivers choice (D.C) and RuttOpt. All <strong>of</strong> <strong>the</strong> methods work on <strong>the</strong> same type <strong>of</strong> data: a set <strong>of</strong><br />
spatially separated nodes, representing farms and abattoirs, each farm having a number <strong>of</strong> animals<br />
to be transported to an abattoir. C.W is a heuristic commonly used in route planning and works by<br />
iteratively connecting nodes to find <strong>the</strong> ones that minimizes costs (distances) (Clarke & Wright<br />
1964). D.C is based on C.W but works in a more random fashion, reflecting realistic choices made<br />
by <strong>the</strong> drivers. This algorithm uses a distance dependent probability distribution to connect farms on<br />
a route. For more details on C.W and D.C see Håkansson (2012). RuttOpt is a route optimization<br />
algorithm originally developed for <strong>the</strong> forest industry. It utilizes a modified unified tabu search algorithm<br />
to find optimal routes from farms to slaughterhouse (Andersson et al. 2008).<br />
To test <strong>the</strong> C.W and D.C heuristics, areas from three densely farmed regions in Sweden, each <strong>of</strong> 10<br />
000 km 2 were chosen. 1-16 animals were randomly assigned to each farm and <strong>the</strong> two heuristics<br />
were used to create transport solutions for each <strong>of</strong> <strong>the</strong> regions. For <strong>the</strong> RuttOpt method <strong>the</strong> five<br />
largest abattoirs in Sweden were chosen and 52 cases were constructed for each <strong>of</strong> <strong>the</strong>m. The cases<br />
contained all <strong>the</strong> registered transport events for each week <strong>of</strong> <strong>the</strong> year 2008 related to <strong>the</strong> particular<br />
abattoirs, describing from what farm and how many animals were sent. RuttOpt was <strong>the</strong>n used to<br />
construct routes for each case.<br />
The results from <strong>the</strong> three methods were <strong>the</strong>n set in relation to <strong>the</strong> equivalent results when only 1<br />
farm was allowed on each route. This was not considered as a realistic scenario but it allowed comparison<br />
<strong>of</strong> <strong>the</strong> relative efficacy <strong>of</strong> each method.<br />
Spatial analysis <strong>of</strong> slaughter capacity<br />
A trend in <strong>the</strong> slaughter industry within Sweden and Europe has been that fewer large abattoirs constitute<br />
a larger part <strong>of</strong> <strong>the</strong> total capacity. In Sweden <strong>the</strong> amount <strong>of</strong> abattoirs slaughtering 90 % <strong>of</strong> <strong>the</strong><br />
cattle was reduced from 26 to 14 abattoirs between <strong>the</strong> years 1985 and 2002, with longer transport<br />
distances as a result (Kaspersson & Gullstrand 2004). In 2008 <strong>the</strong> ten largest abattoirs slaughtered<br />
91 % <strong>of</strong> pigs and cattle (out <strong>of</strong> 62 abattoirs). This affects transport distances as some animals will<br />
have to be transported far<strong>the</strong>r if <strong>the</strong>re is insufficient local slaughter capacity.<br />
Two methods were used to quantify <strong>the</strong> importance <strong>of</strong> <strong>the</strong> distribution <strong>of</strong> slaughter capacity in Sweden.<br />
The first method use virtual landscapes that were created using discrete Fourier transformation<br />
to generate a representation <strong>of</strong> farms in a landscape (Håkansson 2012). Both large and small slaughterhouses<br />
were added to <strong>the</strong> virtual landscapes, and <strong>the</strong> C.W algorithm was used to measure <strong>the</strong><br />
differences in distance that resulted from varying <strong>the</strong> amount <strong>of</strong> abattoirs.<br />
The second method involved creating a model <strong>of</strong> <strong>the</strong> complete slaughter transport system <strong>of</strong> 2008.<br />
The system was <strong>the</strong>n optimized such that each farm sent its animals to <strong>the</strong> abattoir that will minimize<br />
<strong>the</strong> total distance traveled. Abattoirs were <strong>the</strong>n removed one by one and <strong>the</strong> resulting total<br />
transport distances recorded. The outcome <strong>of</strong> <strong>the</strong> model was compared to <strong>the</strong> actual transports that<br />
took place in 2008 (Håkansson 2012).<br />
Results<br />
Route optimization<br />
The D.C algorithm was <strong>the</strong> least successful in reducing <strong>the</strong> distances that <strong>the</strong> transport vehicles<br />
travel, resulting in 15-35 % lower distances compared to if <strong>the</strong> trucks only stop at one farm each<br />
route. The corresponding value for C.W was 40 % and for RuttOpt <strong>the</strong> distances were reduced by<br />
59 %. The mean number <strong>of</strong> stops for D.C was between 1.72-1.73 (varying between 1.53 and 1.88)<br />
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