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Exports to Saudi Arabia re-commenced in July 2005 and contributed to the increase in total sheep numbers exported for the 2005 year and particularly to an increase in
numbers for the second half of that year.
The age of sheep exported has also consistently fallen through the late 1990s and early 2000s and this has been attributed to general reductions in sheep numbers as
well as changing flock structures to favour lamb production rather than wool production.
Since 2005, there has been less large scale fluctuation in total sheep numbers exported.
5.2 Summary statistics for mortalities
When summarised over all ports, older wethers appeared to have higher mortality rates than younger wethers hoggets and lambs and rams appeared to have higher
mortality rates than wethers with an age associated decline adult rams hogget rams ram lambs.
There was also a seasonal pattern to mortality reports with voyage mortality rates being higher in the second half of the year compared to the first half of the year.
Depending on particular years when summary data were presented the pattern appeared more or less marked in different locations Fremantle, Portland, Adelaide
and this is presumably related to seasonal conditions and sheep characteristics.
There was an increase in mortality rates from 2000 to 2001 for Adelaide and Portland with the increase appearing in loading and voyage phases.
Norris and Norman 2003 indicated that there were elevated deaths in Portland in July and August 2002 in association with salmonellosis outbreaks.
There was a major reduction in mortality rates for Portland in 2003 2004 compared to 2002 and a smaller reduction for Adelaide. These reductions coincided with a
major drop in sheep exported through these ports.
Export of sheep from southern ports to the Middle East in winter months
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Table 5.1: Summary statistics for sheep exports from 2001-2009. Compiled from annual reports produced for MLA.
Port Variable
2001 2002 2003 2004 2005 2006 2007 2008 2009
Fremantle No. of sheep
4,279,734 3,359,463
3,007,980 2,821,304
3,450,944 3,295,235 2,975,179
3,150,885 2,558,183
No. of
voyages 76 96 65 44 48 47 43 50 42 No. voyages 2
death 5 3 0 1 2 0 2 1 1
Mortality rate voyage
only 0.65 0.61 0.56 0.46 0.73 0.63 0.66 0.61 0.68
all shipboard
deaths 0.96 0.88 0.77
0.71 0.97 0.86 0.96 0.87 0.91 Adelaide
No. of
sheep 1,203,991
1,329,176 843,283 258,175 301,648 289,745 450,726 447,161 291,665
No. of
voyages 24 25 21 9 6 5 10 9 7 No. voyages 2
death 0 2 2 0 0 0 2 0 0
Mortality rate
Export of sheep from southern ports to the Middle East in winter months
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voyage only
1.11 1.01 0.93 0.89 0.54 0.54 0.74 0.67 0.76 all
shipboard deaths
1.48 1.32 1.2 1.15 1 1
1.03 0.97 1.01 Portland
No. of
sheep 1,238,373
1,256,324 694,948 246,960 311,031 497,831 513,677 599,141 696,498
No. of
voyages 19 25 18 8 9 11 13 14 16 No. voyages 2
death 3 6 1 0 0 0 1 0 0
Mortality rate voyage only
1.36 1.27
0.72 0.49
0.51 0.57
0.6 0.36
0.61 all
shipboard deaths
2.1 2.09 1.01 0.78 0.83 0.92 0.99 0.64 0.86 excludes mortalities that occurred on the Cormo Express after it was rejected at Saudi Arabia
Export of sheep from southern ports to the Middle East in winter months
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Table 5.2: Relative risk estimates and associated p-values comparing mortality rates
Comparison 2001 2002 2003 2004 2005 2006 2007 2008 2009
Adelaide compared to Fremantle Relative
risk 1.54 1.50 1.56 1.62 1.03 1.16 1.07 1.11 1.11
p-value 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
Portland compared to Fremantle
Relative risk
2.19 2.38 1.31 1.10 0.86 1.07 1.03 0.74 0.94 p-value
0.001 0.001 0.001 0.001 0.001 0.001 0.022 0.001 0.001 Portland compared to
Adelaide Relative
risk 1.42 1.58 0.84 0.68 0.83 0.92 0.96 0.66 0.85
p-value 0.001 0.001 0.001 0.001 0.001 0.001 0.026 0.001 0.001
The total counts of sheep exported and of deaths derived from Table 5.1 were used to generate relative risks to compare mortality rates. For all years between 2001 and 2009, annual mortality rates for sheep exported from Adelaide were significantly higher than mortality rates for
sheep exported from Fremantle. Relative risk estimates ranged from 1.03 to 1.62.
Export of sheep from southern ports to the Middle East in winter months
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For sheep exported from Portland, mortality rates were significantly higher than Fremantle for years from 2001 to 2004. Since 2004, mortality rates for sheep exported from Portland were significantly lower than for Fremantle for three years 2005, 2008 and 2009 and were significantly
higher for the other two years 2006 and 2007. For sheep exported from Portland, mortality rates were higher than for sheep exported from Adelaide in 2001 and 2002 but they have been consistently lower than Adelaide since that time.
Export of sheep from southern ports to the Middle East in winter months
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Table 5.3: Relative risks comparing annual shipboard mortality rates over time within Ports. Annual mortality rates for each year from 2004 or 2005 onward were compared to three base rates: annual rate for 2003, annual rate for 2004 and the overall rate based on combined data for 2001-2003.
Adelaide Comparison
to: 2004 2005 2006 2007 2008 2009
2003 0.96 0.83 0.83 0.86 0.81 0.84
2001-03 combined
0.85 0.74 0.74 0.76 0.72 0.75 2004
0.87 0.87 0.90 0.84 0.88
Portland Comparison
to: 2004 2005 2006 2007 2008 2009
2003 0.77 0.82 0.91 0.98
0.63 0.85 2001-03
combined 0.42 0.45 0.50 0.53 0.34 0.46
2004 1.06
1.18 1.27
0.82 1.10
p=0.14
All comparisons were statistically significant with the exception of one. The annual mortality rate for sheep exported from Portland in 2007 was not different to the rate for sheep exported from Portland in 2003 p=0.14. All other comparisons were associated with p0.05.
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