Pig Health: Controlling PMWS and PDNS
Practical methods for controlling PMWS
To date, the introduction of Viramatrix fortified feed rations from weaning
is having a noticeably beneficial effect. Coupled with the treatment of individual
sick pigs with serotherapy, "huge" improvements are being reported by
the unit manager. A word of caution however, the critical period is approaching
and over the next few weeks we will see a more complete picture - but things are
looking up!
Serotherapy: Work in serotherapy has been reported from both Spain and
France. In the UK, Jake Waddilove and a few others are trying this approach. Initial
results look promising, however, Jake has warned that this procedure is controversial.
Strict veterinary supervision is required and the serum collected for a farm MUST
come from pigs on that farm to ensure the Medicines Act is not contravened.
We are being specifically vague on this process at present as work is ongoing
by Jake Waddilove and Mike Muirhead to develop an agreed protocol for the procedure.
This is being treated as a matter of urgency and we will keep everyone updated
as things progress. In the meantime please discuss any questions you may have
with your Veterinary Surgeon.
Immuno enhancers - Feed supplements: A clinical observation study is
underway with one of the most promising feed supplements (Viramatrix) which is
high in natural antioxidants, and although it is early days (the pigs are 8 weeks
old), the pigs fed the supplement are looking exteremly fit and healthy and are
currently not showing any typical early PMWS signs. Only time will tell!
Three Golden rules for controlling PMWS
Based on our latest knowledge of these two diseases, this article puts forward
three golden rules for controlling PMWS, and attempts to provides a structured
basis for introducing a farm based action plan to help control the serious problems
the diseases cause.
At the conference the debate ranged from what was, and just as important, what
was not known about the disease and its association with the PCV2 virus, what
research was needed, through to what can be done at a the farm level to help mitigate
some of the consequences of the disease. This article concentrates on the latter
of these.
ThePigSite.com attended the conference and in conjunction with one of our consultants,
Mike Muirhead, have summarised the KEY elements that have been used at farm level
and found to help the situation. These are a mixture of the 20 Madec principles,
development of these principles, and some other ideas that arose from the discussions.
The list of factors presented have been broken down into three categories,
with the aim of providing a clear set of action points. However it is important
to note nearly all the points can be split into just three golden rules. If you
always keep these 3 rules in mind and make efforts to follow their intent, you'll
be on the right track.
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Three Golden rules for controlling PMWS
|
| Rule 1 |
Limit pig-to-pig contact. |
The virus is spread around the farm by pig-to-pig contact. Limit
pig-to-pig contact and you will limit the prevalence of the disease. REMEMBER
pig-to-pig contact can also be INDIRECT by a needle, surgical instrument, muck
or people. Spread can often be to many pigs in a pen or in large common groups
etc. |
| Rule 2 |
"Stress" is a killer. |
Stressed animals are far more likely to become diseased. This
includes not only obvious physical stress factors but also exposure to micro organisms
which cause major stress to the immune system. If the immune system is overactivated,
the PCV2 virus may produce disease, unless there is a good colostral antibody.
THINK - If a procedure causes the pigs to become stressed, ask "can this
be done in a less stressful manner?". |
| Rule 3 |
Good Hygiene |
There is no substitute for good hygiene and biosecurity measures.
Clean, disinfected buildings, clean instruments and good hygiene will all make
a difference. Don't spread disease by needle or other instruments. |
With these 3 key rules in mind, we have listed the specific actions, that can
be taken at farm level to help mitigate the affects of the disease.
To help with implementation we have broken these points down into three categories:
- Management practises you should aspire to do.
- Management practises you should try to achieve.
- Additional things that have been reported to help.
Start with the top list, focusing on a few items at a time. Once these are
in place move onto the second list, actioning a few items at a time. Always bear
in mind the 3 golden rules and ensure everyone's actions meet their intent.
| Things you should aspire to |
| |
Action |
Explanation |
Reason/Benefits |
| 1 |
Farm-wide
All-in, all-out is King. Apply across the farm. If not by building, by enclosed
pen |
Strictly apply these procedures. For it to be successful all-in, all-out means
just that. There are no half measures. It is vital it is done properly. |
Rule 1: The virus appears to pass from pig to pig. The application of all-in,
all-out helps limit this risk, however it only works if it is practised fully
and used in-conjunction with the next point. |
| 2 |
Farm-wide
Apply strict Cleaning and Disinfection procedures. |
Hygiene standards are absolutely critical. Wet down pens using detergent,
Leave for as long as possible to soak, Powerwash off ALL accessible organic material,
Disinfect with Virkon S (or other suitable disinfectant) per instructions. Allow
to dry. |
Rule 3: The virus survives in waste organic matter. If pens are not fully
cleaned and disinfected disease can be passed down the line. Use Virkon S as it
is reported to be the most effective solution for killing the PCV2 virus. Micro-organisms
need water to live, where ever possible allow pens to dry out before re-stocking.
|
| 3 |
Farm-wide
Limit the mixing of pigs to an absolute minimum |
As best as possible, try to maintain pig groups from weaning through to finishing.
|
Rule 1,2: Mixing pigs breaks two rules. It increases pig-to-pig contact and
places the pigs under stress, both of which appear to significantly increase the
prevalence of the disease. |
| 4 |
Farrowing
Good colostrum management |
Colostral immunity would appear to exist, therefore it is vital that piglets
get a good colostrum intake ideally within the first 6 hours of birth, but certainly
within 24 hours. |
Any procedures to enhance colostrum intake need to be taken within 24 hours
of birth. Do not cross foster after this period (see next point) |
| 5 |
Farrowing
Stop Cross-fostering after 24 hours. |
In the first 24 hours piglets are receiving colostrum and any immunity is
high. Once colostrum intake stops the immunity status of the piglets is fixed. |
Rule 1: Cross fostering of piglets after 24 hours may help spread the virus.
This should be avoided where possible. If this procedure needs to be used, set
up a cull sow in a separate house/area specifically for this purpose. |
| 6 |
W-G-F
Solid Partitions between pens |
Where pens of pigs are separated by open barriers, these should ideally be
changed to solid barriers. |
Rule 1: Open partitions allow pig to pig contact. This allows the spread of
the virus increasing the likelihood of disease. Barriers should be designed to
prevent nose-to-nose contact between pigs. |
| 7 |
W-G-F
Lower stocking densities |
The following stocking densities are recommended by Madec:
Weaners: 3 pigs/sq.m.
Grow/Finish: + 0.75 sq.m/pig |
Rule 2: The lower the stocking density the less the pigs are stressed. Less
stress equals healthier pigs. |
| W-G-F = Weaner, Grower and Finisher accommodation |
| Other things you should try to achieve: |
| 8 |
Weaners
Increase access to feeders |
The pigs should have plenty of room to access feeders. Madec recommends at
least 7cm per piglet. |
Rule 2: If piglet have to fight for food, this will increase the stress levels.
Greater access lowers the need to fight for food, lowering stress. |
| 9 |
W-G-F
Improved temperature control |
Limit the temperature variation the pigs are exposed to. Ideally the temperature
should allow the pigs to be comfortable at all times. |
Rule 2: Chilling causes stress, lowers immunity and increases the risk of
infection. |
| 10 |
W-G-F
Reduce pen sizes. |
Madec recommends a pen size of around 13 pigs, or that of one litter. |
Rule 1,2: This may or may not practical depending upon your building layout,
but the fewer number of pigs in a pen, fewer pigs can be infected in any given
group. |
| 11 |
Farrowing
Stop teeth clipping |
Stop clipping teeth and free up some time to action some of the other points.
|
Rule 1: Is it really necessary to clip teeth these days? This only helps spread
the disease. Many producers are reported to have stopped. Why not give it a try!
Alternatively, action as below. |
| 12 |
Farm-wide
Implement strict hygiene measures |
Ensure good hygiene standards when injecting and tail docking. Use new needles,
sterilise instruments etc. |
Rule 1,3: What better way to spread disease than by injecting numerous pigs
with the same needle! It has been suggested that needles and instruments be dipped
in a 2% solution of Virkon S for 60 seconds between pigs to kill the virus. Have
a number of instruments on the go, all stored in Virkon S, and rotate the instruments
as you treat each pig. |
| 13 |
Farrow-W-G-F
Vaccination and Vaccination timing |
Three types of vaccination were discussed: M-hyo. Glässers and PRRS.
Any affects should be monitored. The timing of vaccination should also be reviewed.
Avoid vaccinating piglets around the time of weaning, apply, say one week before
or after. |
Rule 2,3: Vaccination was implicated as a trigger for the disease on some
farms, but on others vaccination had not been used. It was considered the timing
of the M-hyo vaccination might be important on some farms, but if respiratory
problems existed it was considered better to continue. It was suggested the Glässers
vaccine could be more beneficial than not, and the view was the PRRS vaccines
had little effect on the disease (PMWS), but helped to increase growth rates.
Both weaning and vaccination stress the piglets thus doing both together can cause
excessive stress which should be avoided. |
| 14 |
Farm-wide
Prompt removal of sick pigs |
Move sick pigs promptly to the hospital pen. |
Rule 1: The longer sick pigs are left in the pen the greater the likelihood
that other pigs in the pen will become sick. |
| 15 |
Farm-wide
Formalise a "Sick Pig" policy |
Formalise your policy on what you will do with sick pigs in the hospital pen.
Write it down and follow it to the letter. You should be clear on when a pig should
be euthanased or how long it will be given to "recover". |
There is nothing more demoralising than poorly pigs not getting any better.
Be clear and decide what to do with them. It will help staff morale. |
| 16 |
Farm-wide
Good "disposal" of dead pigs |
Do not leave dead pigs uncovered. Remove to a remote area of the farm and
cover over with straw pending disposal. |
The sight of dead pigs is very disturbing to staff and will not help morale.
They act as a constant reminder of the problems. |
| W-G-F = Weaner, Grower and Finisher accommodation |
| Other ideas that have been reported to have a positive effect |
| 17 |
W-G-F
Improve air quality |
Madec recommends the following limits:
NH3 < 10ppm,
CO2 < 0.15% |
Improving the air quality is beneficial because it reduces the development
of respiratory disease |
| 18 |
W-G-F
Sensible flow within buildings (air, animals) |
Improving air flow within a building will help to reduce toxic
gases |
Rule 2: This helps reduce the stress on the respiratory system |
| 19 |
Sows
Feedback |
This principle is based on exposing sows to the pathogen, to increase colostral
immunity which is then passed on to the piglets. |
One option is to feed back grower faeces to pregnant sows between 80 - 90
days gestation. This may or may not be successful, and could make things worst.
Discuss this with your veterinarian. |
| 20 |
Farrowing
Improved nutrition |
The use of immuno-enhancer feed products have been reported to help, however
data as to their effectiveness is limited. One product (Vira Matrix) was reported
as having shown good results. |
Immuno-enhancers are designed to enhance the ability of the pigs immune system
to resist attack from a pathogen. It was also reported that feeding vegetables
(dried carrots) to suckling piglets could help. |
| 21 |
Farrowing
Treat sows/gilts for parasites before farrowing |
Give sows/gilts a good wash and treat for parasites before they enter the
farrowing house |
Rule 2: Parasitic burdens on the sow result in the animal becoming disadvantaged
or in poor condition. In this state its colostrum levels might be compromised
having a detrimental effect on the piglets. In a well managed herd this should
not be an issue. |
| 22 |
Finishing-Farrowing
Serology |
Injecting piglets with a serum created from older healthy pigs who have been
through the system. |
There are several complications with this, not least the legality of doing
it. However, it was reported this procedure had appeared to be beneficial in Spanish
trials, and could be something you might wish to discuss with your veterinarian.
|
| 23 |
W-F-G
Aerial Disinfection |
Aerial disinfection using Virkon S or other suitable disinfectant) may have
an affect on reducing the spread of the virus. |
Rule 3: There was little information on the effectiveness of aerial disinfection,
but a number of producers are trying it. We will endeavour to follow up on this
as these trials progress. |
| 24 |
W-F-G
Water disinfection |
Disinfection of the water reduces the micro-organism challenge presented to
the pigs and improves hygiene. |
Rule 2,3: Less challenge, less stress. |
| W-G-F = Weaner, Grower and Finisher accommodation |
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