Use of statistical process control in a health maintenance programme
Introduction
A comparison between two treatment philosophies was
carried out on a farrow to finish 2700 sow system.
The farm had a history of post-weaning respiratory problems with spikes
of mortality associated with Enzootic pneumonia and Actinobacillus
pleuropneumonia of 7%.
- Standard Veterinary Care
Based on previous clinical evidence the farm was
provided with a prophylactic medication and vaccine programme.
- Health Maintenance
Based on a review of the pig flow, environment and
management of the pigs with minimal prophylactic medication and vaccine
programme. Use of statistical process
control to determine health progress.
Herd Health
Specifics
The farm’s health status:
|
Positive |
Negative |
||
|
Positive |
Negative |
||
|
Negative |
Negative |
||
|
Negative |
Negative |
Treatment
routines
Similarities
Both concepts adopted Mycoplasma hyopneumoniae vaccination at weaning.
Amoxycillin at weaning via water medication for 4 days
at 20 mg/kg bodyweight.
Differences
Standard veterinary care
Parvovirus vaccination to gilts pre-service and sows
at weaning
APP vaccine at 12 weeks and 16 weeks of age
Amoxycillin and tilmicosin via water medication (both
at 20mg/kg bodyweight) for 4 days at weaning and one week later.
Health maintenance
Parvovirus vaccination to gilts pre-service only
APP vaccine not used
No tilmicosin water medication used
Amoxycillin used at weaning for 4 days only.
Chlortetracycline in-feed 400g/t for 14 days
post-weaning.
Review of the ventilation system on the farm – use of
automatic controllers
Adoption of a pig flow model around 115 sows a week to
farrow – 1100 pigs to wean (9.6 per sow).
Results
Health maintenance was employed over 2007 and compared
with results from 2006.
The SPC model utilized was:
a)
points above the upper critical control point = 2 s.d.
b)
8 consecutive points on one side of the mean
c)
3 out of 4 points on one side of the central line (=1
s.d)
Mortality
Standard Veterinary Care
Stats: Mean 2.9%
s.d 1.3 Upper Critical Point 5.5
Large markers indicate periods when system out of control
Health Maintenance
Stats: Mean 3.0%
s.d 1.3 Upper Critical Point 5.6
There was no statistical difference p = 0.52
Costs in 1000 Au$
|
|
Standard Care |
Health Maintenance |
|
Vaccines |
190 |
101 |
|
In-feed |
0 |
20 |
|
In-water |
120 |
8 |
|
Extra repairs |
0 |
30 |
|
Totals |
317 |
159 |
|
Difference |
|
158 |
|
per pig sold - 58,000 pigs per year = $2.72 per pig $158,000 per year |
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Discussion
Veterinarians can make substantial reductions in the
cost of production by encouraging their clients to adopt a health maintenance
programme. The programme does necessitate that the veterinary advisor examines
the whole farm rather than selected populations “at risk”.
The keys are: Ensuring biosecurity standards are set
and met. Pig flow targets are achieved
on a batch programme.
The environment is ideal for production and where the
environment is suboptimal the veterinarian identifies these areas accurately
and offers reasonable ameliorations.
The use of statistical process control can assist to
identify times when the system is out of control and additional treatment
measures are required.
Note in both scenarios the system was “in control” a majority
of the time. Variations around the mean
(both up and down) occur in any production system.
The health maintenance approach can reduce costs while
allowing the veterinarian more input into the system.