live 0101 controlling scabby mouth in the live sheep trade.
final report
Project code:
LIVE.101
Prepared by:
RT Norris and DC Moir
Agriculture Western Australia
Date published:
May 2000
ISBN:
1740361857
PUBLISHED BY
Meat & Livestock Australia Limited
Locked Bag 991
NORTH SYDNEY NSW 2059
Controlling Scabby Mouth in the Live
Sheep Trade
Meat & Livestock Australia acknowledges the matching funds provided by the Australian
Government to support the research and development detailed in this publication.
This publication is published by Meat & Livestock Australia Limited ABN 39 081 678 364 (MLA). Care is taken to
ensure the accuracy of the information contained in this publication. However MLA cannot accept responsibility for
the accuracy or completeness of the information or opinions contained in the publication. You should make your
own enquiries before making decisions concerning your interests. Reproduction in whole or in part of this
publication is prohibited without prior written consent of MLA.
ISBN 1"T403b 185"7
[
[
r
r
r
r
Controlling Scabby Mouth
in the
Live Sheep Trade
l\\lE-\O\
Final Report
r
r
by
RT Norris and DC Moir
Agriculture Western Australia
22 May, 2000
[
l
r
[
l
Agriculture
WESTERN AUSTRAUA
UVECORP
MEAT & LIVESTOCK
AUSTRALIA
[
Controlling Scabby Mouth in the Live Sheep Trade
Final Report to Meat & Livestock Australia
[
Agriculture Western Australia
22 May, 2000
[
[
Project
LIVE. 101
Background
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ｾＬＮＭｯＺＢＧ
.J
The live sheep export industry provides significant income for the Australian agricultural sector.
The live sheep trade accounts for around 13% of the annual national sheep turn off and returns
in excess of $150 million annually to the national economy.
Australia banned exports of Jive sheep to Saudi Arabia in 1990 following repeated rejections by
that country, ostensibly because of high levels of scabby mouth disease. Before the ban, Saudi
Arabia was the main market for Australian sheep taking 45% of the 6-7 million sheep exported
live annually. The rejections were widely publicised in the national and international media.
The publicity adversely affected Australia's international reputation, not just regarding our
livestock in the Middle East region but also for non agricultural products both in the region and
in other. areas of the world.
No sheep have been sent directly to Saudi Arabia in the last 10 years except for a one-off
shipment in 1995 which was also "rejected" by the Saudis because of high levels of scabby
mouth. In 1996, complaints about high levels of scabby mouth in Australian sheep were
received from Jordan and the United Arab Emirates, which had become major markets for our
sheep. In many shipments, 40-60% of sheep were affected and rejections were threatened.
Scabby mouth is a common disease found in all sheep-raising countries. The disease rarely
causes problems of economic significance in Australia, and is usually not observed by
producers. Consequently, most producers considered that their flocks were free of the disease
and preventive action was rarely undertaken in Australia, particularly in Western Australia.
Humans can be infected with the virus and there was widespread fear of the disease both from
the human health aspects and because of concerns about introducing infection to supposedly
clean flocks.
However, many producers began vaccinating at lamb marking in 1997 following a large
extension campaign in Western Australia called "Sqatch to catch the market". From a base of
only a few thousand doses of vaccine used before the campaign, an estimated 5 million doses
were used in 1997 and more than 7 million doses in 1998.
Agriculture Western Australia has initiated a significant research program in support of the
extension campaign. This has involved close collaboration with various sectors of the live
sheep trade, including producers, exporters, shippers and Neil Buchanan in the Middle East.
The research shows that scabby mouth prevalence in sheep on arrival in the Middle East has
fallen from 40-60% before the campaign to 6-10% in 1999.
Although there has been considerable success in controlling scabby mouth during live export,
there are two areas requiring further investigation. First, a small but significant number of
producers are reluctant to use the vaccine because they consider a) that their property is virus
free and do not wish to introduce the live virus with the vaccine orb) that vaccinating all lambs
-1-
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Ｎ［ｾ＠
[
[
[
[
r
at marking time is not justified when they sell only a relatively small number of sheep for live
export. However, many of these producers may be willing to use the vaccine if it could be used
within a few days before trucking from the farm to the pre-embarkation feedlot.
The second area requiring investigation is to establish the effectiveness of the new CSL vaccine
applicator in controlling scabby mouth during live export. Previous research has shown that the
prevalence can vary widely between farm groups of sheep (0% up to 23% in vaccinated sheep)
on arrival in the Middle East. It is known that earlier models of the vaccine applicator did not
deliver an accurate dose of vaccine to each sheep and it is postulated that under-dosing may be
the main reason for the wide variation in prevalence. Other reasons include poor vaccination
technique and loss of immunity between lamb marking and export several months later. Field
testing of the new applicator indicates that it delivers an accurate dose of vaccine, however the
variation in prevalence of scabby mouth after using the new applicator has not been established.
r
Potential Industry Benefit
r
Controlling scabby mouth in the live sheep trade from Australia would eliminate a significant
threat to the future of this strategically important industry. In addition, evidence that Australia
can deliver sheep with consistently less than 5% scabby mouth on arrival in the Middle East
opens the possibility of resuming direct trade with Saudi Arabia.
[
[
[
[
[
｛ｾ＠
[
[,-
The proposed scabby mouth vaccination program for Saudi Arabia is based on two
vaccinations; one at lamb marking time with a second vaccination at least two weeks before
trucking from the farm. However, a small study in June 1999 suggested that a single
vaccination a few days before trucking from the farm may be effective in controlling scabby
mouth (Appendix 1). If confirmed, such an option would significantly reduce vaccination costs
for the Saudi Arabian market and would also provide another alternative for producers who are
currently reluctant to use the vaccine at lamb marking. The study in June was conducted
outside the time of year when scabby mouth levels are usually highest (February-May) and
involved only 8 farm groups of sheep. It is proposed to undertake further research during the
high risk period and to involve a much greater number of farm groups of sheep.
It is also important to establish the effectiveness of the new CSL vaccine applicator in
controlling scabby mouth and in minimising the variation in prevalence between farm groups of
sheep. Low levels of scabby mouth with little variation between farm groups would indicate
that under-dosing and not poor technique or loss of immunity was the main reason for
unsatisfactory control of the disease previously. Good control with the new applicator may
eliminate the need for a second vaccination before trucking for the Saudi market and would
assist in overall efforts to control the disease during export to all markets in the region.
Objectives
By June 2000 to:
1. Establish the effectiveness of a single vaccination, given either a few days before trucking or
on the day of trucking to the feedlot, in controlling scabby mouth in the live sheep trade.
2. Establish the effectiveness of the new CSL vaccine applicator in controlling scabby mouth
in the live sheep trade.
Methodology
The proposed methodology is described below:
a) Pre-trucking study
-2-
:,(
[
ｾ＠
[
[
ｾ＠
[
[
[
[
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Farm groups of sheep will be selected for study after purchase for live export by a commercial
buyer, providing they have not previously been vaccinated against scabby mouth. On each
farm, 150 young sheep will be divided randomly into 3 treatment groups and given an ear tag:
a) vaccinated 7-10 days before trucking to the feedlot; b) vaccinated within 24 hours before
trucking; c) controls not vaccinated.
It is anticipated that between 10 and 20 farm groups of young sheep will be selected for each of
two studies conducted between February and May 2000. Autumn is the time of the year when
scabby mouth is considered to be at highest levels. After arrival in a commercial feedlot in the
Middle East, the trial sheep will be examined indi vi dually by Neil Buchanan and scored for the
presence of scabby mouth lesions.
Although the design is relatively simple, there are considerable logistical difficulties in selecting
the farms and in complying with the commercial constraints of the live sheep trade. For these
reasons, a group of AGWEST officers will need to be on standby in various locations
throughout the sheep raising areas of Western Australia. With minimal notice, they will be
expected to contact the producer, arrange to visit the property and apply the various treatments.
In some cases, the officers will need to re-visit properties to vaccinate the sheep in treatment b)
above.
b) Monitoring study
Farm groups of sheep will be selected on arrival at a pre-embarkation feedlot on two occasions
between February and May 2000 (avoiding the study described above). Approximately 50
sheep per group from about 20 farms will be selected on each occasion providing they are
identifiable to a farm (it is anticipated that some groups will need to be given an ear tag at the
feedlot). The sheep will be examined individually for scabby mouth by Neil Buchanan after
arri val in a commercial feedlot in the Middle East. The previous owner of the sheep will be
interviewed by telephone to determine whether the sheep were vaccinated previously and if so,
whether the new CSL vaccine applicator was used.
Dissemination Strategy
A report will be prepared after the completion of all four studies and distributed to produc.er
groups in Western Australia,live sheep exporters, MLA and LiveCorp. The results will also be
extended to sheep producers by way of AGWEST's Agricultural Memo, rural newspapers,
seminars and radio talks. The information will also be made available to sheep producers and
exporters in other areas of Australia.
Results
[
[
[
[
L
L
Pre-trucking study
Unfortunately, it was not possible to complete the pre-trucking study, despite several attempts.
Regular contact was made with all of the sheep exporters from Western Australia between
February and May in an attempt to find suitable young sheep for the study. However, it proved
extremely difficult to find un-vaccinated lambs eligible for selection. The success of the
vaccination campaign in Western Australia has resulted in relatively few un-vaccinated flocks
being available. Also, consignments of lambs exported have been relatively small recently,
largely because of low numbers of suitable sheep for export from Western Australia.
Nevertheless, the findings of a study undertaken in 1999 (Appendix I), together with other
research where vaccination was given shortly before trucking from the farm, provide some
confidence that vaccination shortly before leaving the farm will effectively control scabby
mouth during sea transport. Consequently, it is doubtful whether further research on the
effectiveness of pre-trucking vaccination is necessary. However, if further research is
-3-
ｾＬ＠
[
[
[
[
[
r
[
considered necessary, it should not be undertaken in Western Australia because of the
difficulties discussed above.
Monitoring study
When a potentially suitable voyage was identified in the first half of 2000, the pte-trucking
study was given priority. However, when it became clear that the pre-trucking study could not
be undertaken for the selected voyage, the monitoring study was attempted. On one occasion
this work had to be abandoned because of competing priorities at the feedlot (simultaneous
receivals for two shipments and loading for a third shipment). Despite these difficulties, the
work was finally undertaken in April, and a report is attached at Appendix 2.
Communications
The report of the monitoring study (Appendix 2) has been widely distributed to AGWEST
veterinarians for production of extension articles in the Agency's Agricultural Memos. The
report has also been distributed to exporters in Western Australia, the state's producer groups
(WAFF & PGA), LiveCorp, senior policy officers in A...FFA, Tony Brightling and Neil
Buchanan.
[
Additional extension will be undertaken from time to time, to maintain the momentum of the
scabby mouth vaccination campaign in Western Australia, and support will be provided to
producers, exporters and others elsewhere in Australia as required.
[
Conclusions
[
A considerable body of knowledge both from the present project and from previous research
clearly indicates that scabby mouth can be controlled effectively during live export of sheep to
the Middle East.
[
[
[
[
[
[
•
•
•
•
•
•
Vaccination is the most effective means of controlling scabby mouth in the live sheep trade.
The cooperation of all sectors of the trade is essential for the success of a large scale
vaccination campaign such as that which has operated in Western Australia in recent years.
A single vaccination at lamb marking has resulted in low levels (4% to 10%) of scabby
mouth at discharge in the Middle East.
Vaccination shortly before leaving the farm is effective in controlling scabby mouth, but is
less convenient for most producers than vaccination at lamb marking.
.
Two vaccinations, with the second vaccination given shortly before export, has resulted in
negligible levels (less than 0.5%) of scabby mouth at discharge.
Scabby mouth is no longer considered an issue of concern in most markets for Australian
sheep in the Middle East.
Budget report
A final budget report is not available at present but is expected to be submitted to MLA in July
2000.
[
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-4-
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[
Appendix 1
[
Prevalence of scabby mouth after pre-trucking vaccination
[
Don Moir*, Richard Norris*, Neil Buchanant and Greg Norman*
* Agricultw-e W A, t Meat & Livestock Australia
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l,
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ｾ＠
23 June, 1999
Background
Management strategies are under investigation to ensure sheep consistently have less than 5%
prevalence of scabby mouth on arrival in the Middle East. Two studies late in 1997 showed
scabby mouth prevalences of 9.2% and 6.5% in lambs vaccinated at marking about 5 months
previously, compared to 41.2% in unvaccinated controls.
A study in April 1998 examined whether a booster vaccinaiion, given on entry to the feedlot
before export, affected the level of scabby mouth on arrival in the Middle East. The results
(Norris et al 1998) showed that the booster vaccination significantly reduced the level of scabby
mouth; young sheep that received the booster had a prevalence of 2.9% compared to 8.0% in
controls that had been vaccinated at marking only. In a repeat of this study in June 1998, lambs
that received a booster vaccination at the feedlot had less than 5% scabby mouth in the Middle
East compared to 9.8% in the controls. Some sheep in this study were not previously
vaccinated, so their booster vaccination was actually a primary vaccination. This group also
had less than 5% scabby mouth in the Middle East.
Ideally, vaccination against scabby mouth should be given at least 14 days before challenge to
allow sufficient time for immunity to develop. However, most sheep for live export are
purchased less than 14 days before trucking to the feedlot. Consequently, there was a need to
examine the effectiveness of vaccinating at times that are more convenient for those involved in
the live sheep trade. The present study was carried out to determine whether a primary
vaccination given either within two weeks of trucking from the farm or within 24 hours before
trucking would achieve less than 5% clinical scabby mouth at discharge in the Middle East.
Method
Sheep that were purchased for live export in May 1999 were selected for study if they were not
previously vaccinated against scabby mouth. On each of eight properties, 150 1998-drop
merino lambs were randomly allocated to three treatment groups of 50 lambs per group and
given a coloured ear tag. The treatment groups were: vaccinated against scabby mouth from 4
to 11 days before trucking from the farm (Orange tags); vaccinated within 24 hours before
trucking (Blue tags); not vaccinated (pink tags).
In most flocks vaccination was carried out by the farmer (flocks 2 and 18 were vaccinated by
AGWEST officers), either on the bare skin around the tailor behind the elbow, using the new
Scabigard® (CSL) applicator. The trial animals were mixed with the rest of the export
consignment on each farm until arrival at the feedlot when :J.!I trial animals from all farms were
grouped and penned separately. The sheep were loaded on a ship at Fremantle after 2 to 4 days
in the feedlot and arrived in Jordan 16 days later.
After arrival at a feedlot in Jordan, the trial sheep were examined for scabby mouth by an
Australian veterinarian and scored for lesion severity using the following system (0 = no scabby
-5-
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[
[
[
mouth; 1 =mild lesions not readily seen; 2 larger lesions easily detected: 3 =extensive readily
visible lesions), Some trial sheep were mixed with the rest of the consignment in the feedlot in
Western Australia or during loading onto the ship and were lost to followup. Other trial sheep
could not be correctly identified to farm group because of errors in reading or recording the ear
tag number in the feedlot in Jordan. These sheep were allocated to flock "99".
Differences between treatment groups were compared using the Chi-squared test.
L
[
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[
Results
The prevalence of scabby mouth (score 2 & 3 lesions) was 0.3% in the group vaccinated 4 to 11
days before trucking, 1.9% in the group vaccinated within 24 hours of of trucking, and 12.1 % in
the control group (p
Project code:
LIVE.101
Prepared by:
RT Norris and DC Moir
Agriculture Western Australia
Date published:
May 2000
ISBN:
1740361857
PUBLISHED BY
Meat & Livestock Australia Limited
Locked Bag 991
NORTH SYDNEY NSW 2059
Controlling Scabby Mouth in the Live
Sheep Trade
Meat & Livestock Australia acknowledges the matching funds provided by the Australian
Government to support the research and development detailed in this publication.
This publication is published by Meat & Livestock Australia Limited ABN 39 081 678 364 (MLA). Care is taken to
ensure the accuracy of the information contained in this publication. However MLA cannot accept responsibility for
the accuracy or completeness of the information or opinions contained in the publication. You should make your
own enquiries before making decisions concerning your interests. Reproduction in whole or in part of this
publication is prohibited without prior written consent of MLA.
ISBN 1"T403b 185"7
[
[
r
r
r
r
Controlling Scabby Mouth
in the
Live Sheep Trade
l\\lE-\O\
Final Report
r
r
by
RT Norris and DC Moir
Agriculture Western Australia
22 May, 2000
[
l
r
[
l
Agriculture
WESTERN AUSTRAUA
UVECORP
MEAT & LIVESTOCK
AUSTRALIA
[
Controlling Scabby Mouth in the Live Sheep Trade
Final Report to Meat & Livestock Australia
[
Agriculture Western Australia
22 May, 2000
[
[
Project
LIVE. 101
Background
[
[
[
[
[
[
[
[
[
[
[
L
L
L
ｾＬＮＭｯＺＢＧ
.J
The live sheep export industry provides significant income for the Australian agricultural sector.
The live sheep trade accounts for around 13% of the annual national sheep turn off and returns
in excess of $150 million annually to the national economy.
Australia banned exports of Jive sheep to Saudi Arabia in 1990 following repeated rejections by
that country, ostensibly because of high levels of scabby mouth disease. Before the ban, Saudi
Arabia was the main market for Australian sheep taking 45% of the 6-7 million sheep exported
live annually. The rejections were widely publicised in the national and international media.
The publicity adversely affected Australia's international reputation, not just regarding our
livestock in the Middle East region but also for non agricultural products both in the region and
in other. areas of the world.
No sheep have been sent directly to Saudi Arabia in the last 10 years except for a one-off
shipment in 1995 which was also "rejected" by the Saudis because of high levels of scabby
mouth. In 1996, complaints about high levels of scabby mouth in Australian sheep were
received from Jordan and the United Arab Emirates, which had become major markets for our
sheep. In many shipments, 40-60% of sheep were affected and rejections were threatened.
Scabby mouth is a common disease found in all sheep-raising countries. The disease rarely
causes problems of economic significance in Australia, and is usually not observed by
producers. Consequently, most producers considered that their flocks were free of the disease
and preventive action was rarely undertaken in Australia, particularly in Western Australia.
Humans can be infected with the virus and there was widespread fear of the disease both from
the human health aspects and because of concerns about introducing infection to supposedly
clean flocks.
However, many producers began vaccinating at lamb marking in 1997 following a large
extension campaign in Western Australia called "Sqatch to catch the market". From a base of
only a few thousand doses of vaccine used before the campaign, an estimated 5 million doses
were used in 1997 and more than 7 million doses in 1998.
Agriculture Western Australia has initiated a significant research program in support of the
extension campaign. This has involved close collaboration with various sectors of the live
sheep trade, including producers, exporters, shippers and Neil Buchanan in the Middle East.
The research shows that scabby mouth prevalence in sheep on arrival in the Middle East has
fallen from 40-60% before the campaign to 6-10% in 1999.
Although there has been considerable success in controlling scabby mouth during live export,
there are two areas requiring further investigation. First, a small but significant number of
producers are reluctant to use the vaccine because they consider a) that their property is virus
free and do not wish to introduce the live virus with the vaccine orb) that vaccinating all lambs
-1-
.gre
Ｎ［ｾ＠
[
[
[
[
r
at marking time is not justified when they sell only a relatively small number of sheep for live
export. However, many of these producers may be willing to use the vaccine if it could be used
within a few days before trucking from the farm to the pre-embarkation feedlot.
The second area requiring investigation is to establish the effectiveness of the new CSL vaccine
applicator in controlling scabby mouth during live export. Previous research has shown that the
prevalence can vary widely between farm groups of sheep (0% up to 23% in vaccinated sheep)
on arrival in the Middle East. It is known that earlier models of the vaccine applicator did not
deliver an accurate dose of vaccine to each sheep and it is postulated that under-dosing may be
the main reason for the wide variation in prevalence. Other reasons include poor vaccination
technique and loss of immunity between lamb marking and export several months later. Field
testing of the new applicator indicates that it delivers an accurate dose of vaccine, however the
variation in prevalence of scabby mouth after using the new applicator has not been established.
r
Potential Industry Benefit
r
Controlling scabby mouth in the live sheep trade from Australia would eliminate a significant
threat to the future of this strategically important industry. In addition, evidence that Australia
can deliver sheep with consistently less than 5% scabby mouth on arrival in the Middle East
opens the possibility of resuming direct trade with Saudi Arabia.
[
[
[
[
[
｛ｾ＠
[
[,-
The proposed scabby mouth vaccination program for Saudi Arabia is based on two
vaccinations; one at lamb marking time with a second vaccination at least two weeks before
trucking from the farm. However, a small study in June 1999 suggested that a single
vaccination a few days before trucking from the farm may be effective in controlling scabby
mouth (Appendix 1). If confirmed, such an option would significantly reduce vaccination costs
for the Saudi Arabian market and would also provide another alternative for producers who are
currently reluctant to use the vaccine at lamb marking. The study in June was conducted
outside the time of year when scabby mouth levels are usually highest (February-May) and
involved only 8 farm groups of sheep. It is proposed to undertake further research during the
high risk period and to involve a much greater number of farm groups of sheep.
It is also important to establish the effectiveness of the new CSL vaccine applicator in
controlling scabby mouth and in minimising the variation in prevalence between farm groups of
sheep. Low levels of scabby mouth with little variation between farm groups would indicate
that under-dosing and not poor technique or loss of immunity was the main reason for
unsatisfactory control of the disease previously. Good control with the new applicator may
eliminate the need for a second vaccination before trucking for the Saudi market and would
assist in overall efforts to control the disease during export to all markets in the region.
Objectives
By June 2000 to:
1. Establish the effectiveness of a single vaccination, given either a few days before trucking or
on the day of trucking to the feedlot, in controlling scabby mouth in the live sheep trade.
2. Establish the effectiveness of the new CSL vaccine applicator in controlling scabby mouth
in the live sheep trade.
Methodology
The proposed methodology is described below:
a) Pre-trucking study
-2-
:,(
[
ｾ＠
[
[
ｾ＠
[
[
[
[
[
[
[
[
Farm groups of sheep will be selected for study after purchase for live export by a commercial
buyer, providing they have not previously been vaccinated against scabby mouth. On each
farm, 150 young sheep will be divided randomly into 3 treatment groups and given an ear tag:
a) vaccinated 7-10 days before trucking to the feedlot; b) vaccinated within 24 hours before
trucking; c) controls not vaccinated.
It is anticipated that between 10 and 20 farm groups of young sheep will be selected for each of
two studies conducted between February and May 2000. Autumn is the time of the year when
scabby mouth is considered to be at highest levels. After arrival in a commercial feedlot in the
Middle East, the trial sheep will be examined indi vi dually by Neil Buchanan and scored for the
presence of scabby mouth lesions.
Although the design is relatively simple, there are considerable logistical difficulties in selecting
the farms and in complying with the commercial constraints of the live sheep trade. For these
reasons, a group of AGWEST officers will need to be on standby in various locations
throughout the sheep raising areas of Western Australia. With minimal notice, they will be
expected to contact the producer, arrange to visit the property and apply the various treatments.
In some cases, the officers will need to re-visit properties to vaccinate the sheep in treatment b)
above.
b) Monitoring study
Farm groups of sheep will be selected on arrival at a pre-embarkation feedlot on two occasions
between February and May 2000 (avoiding the study described above). Approximately 50
sheep per group from about 20 farms will be selected on each occasion providing they are
identifiable to a farm (it is anticipated that some groups will need to be given an ear tag at the
feedlot). The sheep will be examined individually for scabby mouth by Neil Buchanan after
arri val in a commercial feedlot in the Middle East. The previous owner of the sheep will be
interviewed by telephone to determine whether the sheep were vaccinated previously and if so,
whether the new CSL vaccine applicator was used.
Dissemination Strategy
A report will be prepared after the completion of all four studies and distributed to produc.er
groups in Western Australia,live sheep exporters, MLA and LiveCorp. The results will also be
extended to sheep producers by way of AGWEST's Agricultural Memo, rural newspapers,
seminars and radio talks. The information will also be made available to sheep producers and
exporters in other areas of Australia.
Results
[
[
[
[
L
L
Pre-trucking study
Unfortunately, it was not possible to complete the pre-trucking study, despite several attempts.
Regular contact was made with all of the sheep exporters from Western Australia between
February and May in an attempt to find suitable young sheep for the study. However, it proved
extremely difficult to find un-vaccinated lambs eligible for selection. The success of the
vaccination campaign in Western Australia has resulted in relatively few un-vaccinated flocks
being available. Also, consignments of lambs exported have been relatively small recently,
largely because of low numbers of suitable sheep for export from Western Australia.
Nevertheless, the findings of a study undertaken in 1999 (Appendix I), together with other
research where vaccination was given shortly before trucking from the farm, provide some
confidence that vaccination shortly before leaving the farm will effectively control scabby
mouth during sea transport. Consequently, it is doubtful whether further research on the
effectiveness of pre-trucking vaccination is necessary. However, if further research is
-3-
ｾＬ＠
[
[
[
[
[
r
[
considered necessary, it should not be undertaken in Western Australia because of the
difficulties discussed above.
Monitoring study
When a potentially suitable voyage was identified in the first half of 2000, the pte-trucking
study was given priority. However, when it became clear that the pre-trucking study could not
be undertaken for the selected voyage, the monitoring study was attempted. On one occasion
this work had to be abandoned because of competing priorities at the feedlot (simultaneous
receivals for two shipments and loading for a third shipment). Despite these difficulties, the
work was finally undertaken in April, and a report is attached at Appendix 2.
Communications
The report of the monitoring study (Appendix 2) has been widely distributed to AGWEST
veterinarians for production of extension articles in the Agency's Agricultural Memos. The
report has also been distributed to exporters in Western Australia, the state's producer groups
(WAFF & PGA), LiveCorp, senior policy officers in A...FFA, Tony Brightling and Neil
Buchanan.
[
Additional extension will be undertaken from time to time, to maintain the momentum of the
scabby mouth vaccination campaign in Western Australia, and support will be provided to
producers, exporters and others elsewhere in Australia as required.
[
Conclusions
[
A considerable body of knowledge both from the present project and from previous research
clearly indicates that scabby mouth can be controlled effectively during live export of sheep to
the Middle East.
[
[
[
[
[
[
•
•
•
•
•
•
Vaccination is the most effective means of controlling scabby mouth in the live sheep trade.
The cooperation of all sectors of the trade is essential for the success of a large scale
vaccination campaign such as that which has operated in Western Australia in recent years.
A single vaccination at lamb marking has resulted in low levels (4% to 10%) of scabby
mouth at discharge in the Middle East.
Vaccination shortly before leaving the farm is effective in controlling scabby mouth, but is
less convenient for most producers than vaccination at lamb marking.
.
Two vaccinations, with the second vaccination given shortly before export, has resulted in
negligible levels (less than 0.5%) of scabby mouth at discharge.
Scabby mouth is no longer considered an issue of concern in most markets for Australian
sheep in the Middle East.
Budget report
A final budget report is not available at present but is expected to be submitted to MLA in July
2000.
[
L
[
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Appendix 1
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Prevalence of scabby mouth after pre-trucking vaccination
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Don Moir*, Richard Norris*, Neil Buchanant and Greg Norman*
* Agricultw-e W A, t Meat & Livestock Australia
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23 June, 1999
Background
Management strategies are under investigation to ensure sheep consistently have less than 5%
prevalence of scabby mouth on arrival in the Middle East. Two studies late in 1997 showed
scabby mouth prevalences of 9.2% and 6.5% in lambs vaccinated at marking about 5 months
previously, compared to 41.2% in unvaccinated controls.
A study in April 1998 examined whether a booster vaccinaiion, given on entry to the feedlot
before export, affected the level of scabby mouth on arrival in the Middle East. The results
(Norris et al 1998) showed that the booster vaccination significantly reduced the level of scabby
mouth; young sheep that received the booster had a prevalence of 2.9% compared to 8.0% in
controls that had been vaccinated at marking only. In a repeat of this study in June 1998, lambs
that received a booster vaccination at the feedlot had less than 5% scabby mouth in the Middle
East compared to 9.8% in the controls. Some sheep in this study were not previously
vaccinated, so their booster vaccination was actually a primary vaccination. This group also
had less than 5% scabby mouth in the Middle East.
Ideally, vaccination against scabby mouth should be given at least 14 days before challenge to
allow sufficient time for immunity to develop. However, most sheep for live export are
purchased less than 14 days before trucking to the feedlot. Consequently, there was a need to
examine the effectiveness of vaccinating at times that are more convenient for those involved in
the live sheep trade. The present study was carried out to determine whether a primary
vaccination given either within two weeks of trucking from the farm or within 24 hours before
trucking would achieve less than 5% clinical scabby mouth at discharge in the Middle East.
Method
Sheep that were purchased for live export in May 1999 were selected for study if they were not
previously vaccinated against scabby mouth. On each of eight properties, 150 1998-drop
merino lambs were randomly allocated to three treatment groups of 50 lambs per group and
given a coloured ear tag. The treatment groups were: vaccinated against scabby mouth from 4
to 11 days before trucking from the farm (Orange tags); vaccinated within 24 hours before
trucking (Blue tags); not vaccinated (pink tags).
In most flocks vaccination was carried out by the farmer (flocks 2 and 18 were vaccinated by
AGWEST officers), either on the bare skin around the tailor behind the elbow, using the new
Scabigard® (CSL) applicator. The trial animals were mixed with the rest of the export
consignment on each farm until arrival at the feedlot when :J.!I trial animals from all farms were
grouped and penned separately. The sheep were loaded on a ship at Fremantle after 2 to 4 days
in the feedlot and arrived in Jordan 16 days later.
After arrival at a feedlot in Jordan, the trial sheep were examined for scabby mouth by an
Australian veterinarian and scored for lesion severity using the following system (0 = no scabby
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mouth; 1 =mild lesions not readily seen; 2 larger lesions easily detected: 3 =extensive readily
visible lesions), Some trial sheep were mixed with the rest of the consignment in the feedlot in
Western Australia or during loading onto the ship and were lost to followup. Other trial sheep
could not be correctly identified to farm group because of errors in reading or recording the ear
tag number in the feedlot in Jordan. These sheep were allocated to flock "99".
Differences between treatment groups were compared using the Chi-squared test.
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Results
The prevalence of scabby mouth (score 2 & 3 lesions) was 0.3% in the group vaccinated 4 to 11
days before trucking, 1.9% in the group vaccinated within 24 hours of of trucking, and 12.1 % in
the control group (p