CELL TUMORS IN PIGS:
by Beth A. Valentine, DVM, PhD
Barbara Baker noticed that Lord had developed a lump on his
right cheek, she didn’t give it much thought. It was about the
size of a cherry, and was not growing, bleeding, changing
shape or color, or otherwise bothering the pig. It was only
when Dr. Lawhorn, who was attending the potbellied pig
symposium in Florida, visited her home and examined Lord’s
lump that she became concerned. Dr. Lawhorn advised Barbara to
have the lump removed and sent for pathologic examination. A
few weeks later the surgery was performed. It was easy for the
veterinary pathologist to identify the characteristic features
of a mast cell tumor, but it was almost impossible for the
pathologist, or anyone else for that matter, to offer an idea
of what might happen now that the tumor was removed. We just
don’t know enough about mast cell tumors in pigs to be able to
predict their behavior.
When Barbara asked if I
would be willing to write an article on mast cell tumors in
pigs, I went to my files to see what I could find. There is
precious little written about mast cell tumors in pigs, so at
least I didn’t have to wade through a lot of material! In this
article I will try to summarize what we do know about mast
cell tumors in pigs and in other species.
First off, let me
explain what a mast cell is. Mast cells are normal residents
of the areas of the body that are exposed to what can be
considered an "external" environment. This includes
the skin, sinuses, the lining of the airways from the nose to
the lungs, and the lining of the stomach and intestines. Mast
cells are identified by their characteristic granules. The
purpose of mast cells is to release the contents of their
granules during infections. The granules of mast cells contain
a variety of substances, many of which make blood vessels
"leaky," which helps other inflammatory cells to get
to the site of an infection to try to clear it up. This normal
role is often overlooked in discussions of mast cells, because
mast cells are so often involved in allergic responses.
Allergies can be considered a form of "healthy"
inflammation gone awry. One of the substances that mast cells
produce and release is histamine, which is the basis for the
use of antihistamines in allergic conditions. Histamines cause
vessels to be leaky, which leads to fluid accumulation and
tissue swelling, and often cause an itching sensation in the
Tumors of mast cells,
called either mast cell tumors or mastocytomas, are common in
dogs, cats, and ferrets, and are much less common in horses,
cattle, pigs and people. We know a lot about the behavior of
mast cell tumors in dogs, cats, ferrets, and horses, but very
little about their behavior in cattle and pigs. Such tumors
are very uncommon in people, usually occurring in children,
where they often regress on their own. In dogs, mast cell
tumors are graded 1, 2 and 3, with grades 1 and 2 being
relatively benign and generally cured by wide surgical
excision, and grade 3 being malignant and likely to recur
and/or spread. Mast cell tumors in cats are most often benign,
although there is a less common malignant variant. Mast cell
tumors in ferrets and horses are considered benign tumors. In
cats, the most common mast cell neoplastic processes are skin
tumors (that can be multiple), and an internal mastocytosis
syndrome in which neoplastic mast cells infiltrate multiple
internal organs. In the cat, these appear to be two distinct
Adding to the confusion
is that there is a condition called mastocytosis, in which
mast cells are increased throughout the body, creating havoc
by producing their inflammation-promoting substances. In some
cases the mast cells themselves are not thought to be
neoplastic, but in others they are. I should define the term
neoplastic here. Neo means new, and plastic means growth, so a
neoplasm is a growth of new tissue. Neoplasia can be benign,
meaning that the tumor does not invade or spread. Malignant
tumors invade and/or spread through the body, causing what is
often called cancer. The term cancer comes from the Latin word
for crab, because the spread of cancer can resemble the
spreading legs of a crab. And, to make matters worse, there is
also a condition in which neoplastic mast cells circulate in
the blood, known as mast cell leukemia.
regarding mast cell disorders in pigs includes mast cell
tumors, mastocytosis, and mast cell leukemia. Mast cell tumors
of the skin or of internal organs are the most common mast
cell problems in pigs, and have even been reported in young
meat pigs examined at slaughterhouses. These tumors are not
common in young pigs, though, with one study citing only 5
cases of mast cell tumors of the skin in 664 million pigs
Barbara was able to
find me pathology reports from three other potbellied pigs
with mast cell tumors. Two were single tumors, similar to
Lord’s, and another pig had multiple mast cell tumors in the
skin. The ages recorded were around 7 years of age. The pig
with multiple tumors had re-growth of three of the tumors
following removal. So far, I have not seen any reports of
internal mast cell tumors in potbellied pigs. But, given
findings in other breeds of pigs, I suspect that this is a
possibility. The behavior of mast cells tumors is often
described as unpredictable, usually because we simply don’t
know enough to be able to predict it. This is certainly the
case with mast cell tumors in pigs. From what I can gather
from the literature to date, mast cell tumors in pigs appear
to be more similar to cats than to other species. That is,
tumors that form in the skin may be multiple and can recur
following incomplete excision, but they tend to stay in the
skin. Tumors that form internally are not often associated
with skin tumors. I hasten to add that this is still
speculation, based on a very small number of reported cases of
mast cell neoplasia in pigs. We still have a lot to learn
about mast cell tumors in pet pigs.
So, what should you do
if your pig develops a skin lump? My best advice is to have it
examined by a veterinarian and removed as soon as possible. A
mast cell tumor that is completely removed early on is far
less likely to recur or to spread than is one that has been
there for awhile. The veterinary surgeon will aim to remove
the tumor as widely as possible, and removing a small tumor is
much preferred to waiting for it to grow to a really worrisome
size. Always insist on sending the sample for pathologic
It is only by removing
tumors and having them identified as mast cell tumors, and
then following up on the pigs to see what happens, that we
will be able to learn about the behavior of mast cell tumors
in potbellied pigs. The efforts of people like Barbara Baker
and of organizations like the Duchess Fund are to be lauded.
Only by continuing to gather and examine data on disorders of
potbellied pigs will we be able to learn more about these
vexing tumors, as well as other problems that plague
Beth A. Valentine, DVM,
PhD, is a board-certified veterinary pathologist on the
faculty of the College of Veterinary Medicine at Oregon State
University, Corvallis, OR.
REPRODUCTIVE RESPIRATORY SYNDROME by: Bruce Lawhorn, DVM, MS
Reproductive Respiratory Syndrome (PRRS) is one of the most
important diseases in the domestic swine industry. As the name
implies, PRRS causes reproductive and respiratory disease.
PRRS actually is a new worldwide swine disease that was not
even recognized before the late 1980s. The disease pattern in
domestic swine herds caused by PRRS virus infection was
actually called "mystery swine disease" for several
years until the cause was discovered and proven to be a virus
in 1991. It was named the Lelystad virus because the location
of its discovery at the Central Veterinary Research Institute
in Lelystad, Netherlands. Since that time, many strains of
PRRS virus have been recognized. With the exception of mallard
ducks, other animals and humans are not known to be hosts for
the PRRS virus of swine.
It is still unknown where PRRS virus originated or how it was
introduced into domestic swine. Free-roaming feral swine in
the US and wild boar in other countries were thought to be
likely sources. Obviously feral and wild swine were in
existence a long time before PRRS emerged, but they could have
been infected with PRRS virus from some unknown source and
then made contact with domestic swine and infected them. In a
joint Texas Agricultural Extension Service/Texas Parks &
Wildlife 1996 – 1999 survey in the Texas Rolling Plains, only
1/135 samples tested positive by the PRRS ELISA antibody test.
This PRRS positive animal was a twenty-month-old, 155 pound
boar. 1 In a US survey of feral swine, all sera collected and
tested between 1976 and 1993 were negative and only 2
positives were found in 1994.2 Only 2/1250 wild boar samples
collected in Europe from 1991 through 1996 were PRRS
positive.2 From these US and European surveys it was
speculated that domestic swine probably transmitted PRRS virus
to feral and wild swine, and not vice versa. 1, 2
Another wild species, the mallard duck, has been proven to be
susceptible to PRRS virus infection and has extended virus
shedding (39 days after exposure in some).3 It is interesting
that PRRS virus is very fragile and is inactivated in an
unprotected environment at room temperature, but can survive
in room temperature well water and city water for 8 and 11
days, respectively. Mallard ducks can be infected through PRRS-contaminated
water and shed virus into feces to infect other mallard ducks.
PRRS virus isolated from mallard duck feces has been shown to
be infectious for pigs when challenged intranasally; these
infected pigs were then able to infect susceptible contact
pigs. Scientists discount the idea that mallard ducks have
spread PRRS virus to and between swine herds probably because
duck to pig contact is very infrequent in modern swine
production. However, many swine farms around the world with
less intensive production practices have frequent duck to pig
contact. Although it is unknown where PRRS virus originated,
scientist do agree that mallard ducks could be a possible host
for introduction of different strains of PRRS virus into swine
in the future.3
It was not likely that PRRS virus infection in US domestic
swine originated from PBPs since there was already a low PRRS
prevalence in domestic swine in Iowa by 1985 (shown by
retrospective studies)2, and PBPs did not become popular as US
pets until the late 1980’s (the time of emergence of
"mystery swine disease"). However, it would be
interesting to know if there is currently any evidence of PRRS
virus infection in the PBP population of the US.
Recently, 29 sera from normal PBPs of various ages, sex and
weights from a Florida location were blood sampled and tested
for PRRS antibody by the ELISA test. All 29 sera were
negative. When infection to PRRS virus in swine does occur,
antibody to the PRRS virus detectable by ELISA persists for
about 4 to10 months. Since the average age for these 29 PBPs
was 2.6 years (9 month – 6 years range), it is possible that
PRRS virus infection in some animals could have occurred
previously but antibody was no longer detectable at the time
of sampling. Although this is a very small survey and has the
aforementioned limitation, it may indicate that, like feral
swine, PRRS virus infection is probably not important as a
cause of disease in PBPs. Testing other populations of PBPs
could substantiate this hypothesis.
1. Lawhorn B. Texas
Rolling Plains Feral Swine Survey, Proceedings of the 1999
National Feral Swine Conference, Ft. Worth, Texas, 124-127.
2. PRRS Compendium.
National Pork Producers Council, Des Moines, Iowa, 1998, 61,
3. Benefield DA,
Collins JE, Dee SA, et al. Porcine Reproductive and
Respiratory Syndrome. In:Straw BE, D’Allaire S, Mengeling WL,
et al, eds. Diseases of Swine, Eighth edition, Ames: Iowa
State University Press, 1998; 201-232.
SYNDROME – PART I
The Duchess Fund recently has received medical
reports on two purebred potbellied pigs from
registered stock involving Porcine Stress
Syndrome (PSS). PSS is also known as
CASE A – CONFIRMED (Case #000196 – Duchess
Fund Medical Database) The first case was in
July, 2000 when a pig expired on the table at a
university during a routine spay. PSS was
suspected so a cardiac puncture was done and
blood sent off for DNA testing. The result of the
DNA test was homozygous, HAL 1843 dm, which means
she was a dimutant or had two copies of the
mutant PSS gene and malignant hyperthermia (same
as PSS) was the cause of death. A complete
summary will be in Part II.
CASE B – SUSPECT (Case #000197 – Duchess Fund
Medical Database) The second case was on a
young piglet with a history of being easily
stressed. It was reported that she had a
difficult recovery following her spay. The pig
expired approximately 3 months after the spay.
The owners took the pig to a university for a
necropsy. We have the pathology report as well as
the liver tissue analysis. There was no selenium
deficiency. Fresh blood was not available for DNA
testing because the pig had expired hours before
reaching the university. However, based on the
history of the pig, microscopic change in muscle
tissue and the selenium tissue analysis of the
liver, the parents are being DNA tested for PSS.
Test results will be in Part II as well as a
Naturally, this has
raised many questions from concerned pet pig
owners. In an effort to better explain this
genetic syndrome, we asked Barbara Straw, DVM,
PhD, to share her expertise on the subject for
the benefit of potbellied pig owners. Dr. Straw
is the Editor-In-Chief of "Diseases of
Swine" 8th edition.
The following is an interview on 9/21/00
conducted by The Duchess Fund:
Duchess Fund: Dr. Straw, could you explain in
layman’s language what Porcine Stress Syndrome is
(also known as malignant hyperthermia) ?
Dr. Straw: Porcine Stress Syndrome (PSS
for short) is an inherited defect in muscle
metabolism that can be life-threatening to the
pig under certain triggering situations. Pigs
with PSS have a defect in the transport channel
that moves calcium into their muscle cells.
Normally for a muscle to contract, calcium must
be moved from outside the cell to inside. In
certain situations, this defect in which the
muscle is trying to function without the right
level of calcium results in abnormal muscle
metabolism in which lactic acid builds up.
Accompanying the acidosis is a build-up of heat
due to a wasteful process of utilizing muscle
glycogen for energy. The acidosis and
hyperthermia can be severe enough to cause death.
PSS is caused by a recessive gene. When animals
carry two copies of the gene they are prone to
showing clinical signs when certain stresses are
Fund: What is the difference between PSS and
White Muscle Disease?
Dr. Straw: White Muscle disease occurs
because of a deficiency of an essential nutrient,
selenium. Selenium is part of an enzyme that
removes peroxidase waste products from liver,
muscle and many other cells in the body When
peroxidases accumulate in muscle they damage the
tissue and it blanches out producing a
"white muscle". While both PSS and
selenium deficiency produce damage to muscle,
they have completely different causes.
Fund: Since PSS is a genetic disease, could a
supplement of Vitamin E and/or Selenium or any
other vitamin/mineral supplement prevent symptoms
or prevent death from PSS?
Dr. Straw: No. PSS is a genetic disorder
not a nutritional deficiency and the nutritional
status of a pig has not been shown to affect the
expression of PSS. Supplementation with selenium
or Vitamin E would not influence the expression
of PSS since they are caused by two separate
mechanisms. Calcium supplementation would not
help either since there is plenty of calcium
outside the muscle cell, but the cellular
transport channel isn’t working properly.
Fund: Under what conditions are pigs with PSS
likely to show symptoms and possibly die?
Dr. Straw: Transportation, high
environmental temperatures, exercise, mating and
fighting can trigger muscle damage. Also certain
compounds such as halothane anesthetic,
succinylcholine and caffeine directly act on the
calcium transport channel.
Fund: What is Dantrolene, how and when is it
used and how effective is it?
Dr. Straw: Dantrolene is a drug given by
injection that acts to stabilize the calcium
transport channel. It has moderate to high
effectiveness in treating an episode of PSS if
given immediately after signs are noticed.
However, because PSS is not a common condition,
few veterinary clinics stock this drug.
Fund: Can a pig have a non-fatal PSS episode
without spiking a high temperature?
Dr. Straw: An elevation in temperature is
a consistent finding with PSS. The abnormal
muscle metabolism generates excess heat that
raises the rectal temperature. Events such as
exercise or fighting that trigger an episode of
PSS may also raise the pig’s temperature. While
an elevation in temperature by itself is not
diagnostic, a pig with a normal temperature
subjected to such events, is not likely to be
experiencing a PSS episode.
Fund: If a veterinarian treats a pig that
subsequently dies, what should that veterinarian
do to confirm PSS if it was suspected?
Dr. Straw: When a pig dies after stressful
physical activity or anesthesia, the first thing
to do is take its temperature. PSS produces
extreme elevations in body temperature, typically
as high as 106 degrees F at the time of death.
Even some time after death the muscle temperature
will still be elevated. Next check for extreme
rigidity of the legs. The abnormal events in the
muscle produce immediate rigor mortis. The
definitive test is to directly check for the
defective gene, called HAL-1843. This test
requires a sample of blood or tissue to be sent
to a lab that performs DNA analysis. The
laboratory will report whether the pig has two,
one, or no copies of the HAL-1843 gene.
Barbara Straw, DVM, PhD
Professor Swine Medicine
Michigan State University
appreciate Dr. Straw taking the time to address
this issue and thank her
for her assistance!
As you can see, PSS is an inherited defect in
muscle metabolism. Dr. Straw has outlined the
causes and symptoms of this syndrome as well as
the steps that should be taken to diagnose and
At this time it is unknown if Case A is an
isolated case or if there are more potbellied
pigs carrying the gene. As for Case B, the DNA
test results on the pigs’ parents will determine
whether or not PSS was involved in the cause of
death. Many swine experts believe that PSS is a
minimal problem in potbellied pigs. We need more
information and monitoring to confirm this.
If you are interested in having your pig
tested for PSS, the following needs to be done:
Contact: Ed Kenney at Swinetics, phone
877-440-0894 who will register you free of
- After registration with Swinetics, contact
Jarrod Watson at GeneScreen, phone 800-752-2774
and he will send you the material for the card
test which consists of a few drops of your pigs
blood placed on a card and mailed to their lab.
Registration with Swinetics first will reduce the
cost of this test. Please furnish a copy of the
test results to your veterinarian and The Duchess
Fund so we can document it.
In Part II of PSS, we will be covering stress
reducing management practices, alternative
methods of medical management of pigs as well as
the summaries of these cases.
If you have questions, please email them to or
fax to 813-645-1625. Answers to your questions will also be covered in
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corporation whose purpose is to enlarge the
amount and enhance the quality of data available
to the individual practitioner relative to the
care and needs of potbellied pigs as long term
companion animals. Your donations make it
possible for us to continue our important work
and obtain our goals and accomplish our
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Copyright September, 2000 The Duchess Fund All
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SYNDROME – PART II
As you read in Part I,
The Duchess Fund has recently received medical records on two
purebred potbellied pigs involving Porcine Stress Syndrome
(PSS). PSS is also known as "Malignant
CASE A –
CONFIRMED (Case #000196 – Duchess Fund Medical Database) A pig
expired on the table during a routine spay. PSS was suspected
so a cardiac puncture was done to obtain fresh blood and it
was sent off for DNA testing. The test result was homozygous
HAL 1843 dm, which means she was a dimutant or had two copies
of the mutant PSS gene and PSS was the cause of death.
Attempts were made to locate the parents of this pig but all
efforts have been unsuccessful. This is believed to be the
first documented (confirmed) case of PSS in a potbellied pig.
CASE B – SUSPECT
(Case #000197 – Duchess Fund Medical Database) This was a
young piglet with a history of being stressed easily. She also
had a difficult recovery from a routine spay. The owners
reported what may have been seizure activity in the pig and
she expired about 3 months after the spay. The pig was
subsequently taken to a university for a necropsy. The liver
was sent to a lab to rule out a selenium deficiency and white
muscle disease. The pathology report indicated death was from
suspected PSS. Since there was no fresh blood available for
DNA testing, it could not be confirmed. Both parents of this
pig were subsequently DNA tested for PSS and both returned as
Due to ongoing
questions from pet pig owners, we have continued with the
following questions that are answered by Bruce Lawhorn, DVM,
Bruce Lawhorn, DVM MS
Associate Professor/Extension Swine Veterinarian
Texas Agricultural Extension Service/Dept Large Animal
Medicine & Surgery
College Veterinary Medicine
The Texas A&M University System
College Station, Texas 77843-2487
Duchess Fund: How
did PSS originate?
Dr. Lawhorn: During the 1930’s through the 1950’s, the
heavy muscled, low fat Pietrain swine breed was developed in
Belgium (by crossing of the local Normand
and Berkshire breeds) to meet the demand for high quality,
extra lean fresh pork. Associated with the selection for heavy
muscling and low fat was the tendency for Pietrain hogs to be
easily stressed by ordinary management practices such as
movement from pen to pen, loading into a trailer and
transportation to market. Sudden death occurred in many of
these animals after becoming stressed. It was also noticed
that pale, soft, exudative (PSE) pork was common in hams and
loin chops from this breed (compared to the uniform pink to
pinkish-red color of normal pork). During this time period,
the cause of this condition was unknown and no real diagnostic
tests other than observation were available to identify what
we now call PSS or malignant hyperthermia (MH).
condition was spread by breeding Pietrain pigs with the PSS
gene to swine in other European countries. It is speculated
that PSS was introduced
into the U.S. through Danish Landrace swine in 1934, and then
became more common when this breed was released to the public
in 1950, resulting in the creation of the American Landrace
breed. However, the Poland China breed which was developed in
Ohio, became well known for having PSS traits. Since the
Berkshire breed was used in the development of both the
Pietrain and Poland China breeds, the PSS mutant gene was
probably introduced by this common ancestry. Poland China hogs
were further selected for heavy muscling and low fat content
as the demand for lard decreased and vegetable oils became
more popular after WW II. This selection process for extremely
lean animals unknowingly increased the occurrence of PSS .
Subsequently the Poland China breed was noted for having a
high prevalence of PSE pork (late 1950’s), became associated
with a high frequency of susceptibility to stress (mid-to-late
1960’s), and was identified with having high prevalence of
reactivity to halothane gas anesthesia (early 1970s).
It is noteworthy that
anesthetizing young pigs with halothane gas was the first
accurate test to identify PSS swine (those having 2 copies of
mutant PSS gene). However, it had the drawback of not
separating carriers (having one copy of the mutant PSS gene)
from normal swine (having no copies of the mutant PSS gene)
since halothane caused no increase in rectal temperature (MH)
or stiffening of the limbs (uncontrolled muscle contraction)
in carrier and normal swine. Nevertheless, it was a good
testing method, because discontinuing halothane anesthesia in
young swine (20 to 40 pounds) after they exhibited elevated
temperature and stiffening of the limbs as signs of PSS,
allowed complete recovery. Older, larger PSS swine such as
sows would not recover from MH induced by halothane
anesthesia; this indicated body muscle mass and the heat and
metabolic disturbances caused by uncontrolled anaerobic muscle
activity influenced the case mortality rate.
By the 1970’s, the
Pietrain, Landrace and Poland China breeds were known for
their high prevalence of PSS. Other domestic swine breeds have
been affected by PSS since that time. Understanding how
widespread PSS had become, it is remarkable that modern DNA
testing throughout the world has established that the PSS
mutation was introduced by a single breeding founder pig!
Duchess Fund: What
is a spontaneous mutation?
Dr. Lawhorn: A mutation is defined as an error or errors
in copying of nucleic acid such as DNA during cell division.
For example, every time the cells of a mammal divide, an exact
copy of DNA code for the new cell is made. Cell division in
mammals occurs billions and billions of times every day.
Mutations or errors in DNA copying may have no consequences or
be the cause of major problems such as cancer.
"Spontaneous" mutation implies that there is no
apparent cause. It is well known that there are specific
causes for cell mutations such as ultraviolet light. Sunscreen
is applied to minimize the mutating effects of ultraviolet
light that can cause skin cell cancer. Scientists use
ultraviolet light in the laboratory as a disinfectant because
it causes errors in DNA replication during bacterial cell
division; bacteria are killed as a result. Spontaneous
mutations may actually have a cause, but the cause may not be
currently known. The immune system of mammals kills mutated
cells if they can be recognized as "different". For
example, the immune system kills "changed" cells
that could become cancer and the mammalian host is totally
unaware this is happening. Some mutations do not alter the
cell enough to signal the immune system to kill it. These
undetected mutations are likely to be passed on during
subsequent cell divisions; this is the case for the PSS
Duchess Fund: What
are the chances of a potbellied pig having a spontaneous
Dr. Lawhorn: Any living organism can experience a
spontaneous mutation or mutations from known causes. As
previously discussed, such mutations may have no consequences
or be life threatening. Inbreeding probably increases the
chances for mutations.
Duchess Fund: In
Part I of PSS, Case A pig test results returned as HAL1843dm.
How does this affect the relatives of the Case A pig? Also,
what is the difference between a carrier and a positive?
Dr. Lawhorn: The results ‘HAL1843dm’ refer to the original
test ‘HAL’ and ‘dm’ means dimutant. The HAL1843dm result for
Case A pig means it had 2 copies of the PSS gene (One copy
from each parent). Inheriting 2 copies of the PSS gene is what
makes a pig a PSS positive animal. Inheriting one copy of the
PSS gene makes a pig a carrier. Inheriting no copies of the
PSS gene means a pig is normal. It takes two carrier parents
that have one copy of the PSS gene to produce 25% offspring
with 2 copies (PSS pigs), 50% offspring with one copy
(carriers), and 25% with no copies of the PSS gene (normal).
So this means the parents and carrier littermates of Case A
pig should not be used for breeding and should be altered to
prevent reproduction. Also, grandparent stock that may still
be reproductively active should be tested and any carriers
found should not be used for breeding. Any littermates of Case
A pig with 2 PSS genes are likely to die after almost any
stress including anesthesia, so PSS is then a fatal or
self-limiting mutation. However, if PSS pigs survive, the
owner will have to avoid almost all stressors on the pig for
it to survive. Of course the only way to know the PSS gene
status of any littermates to a pig that died of lab-confirmed
PSS is to also lab test them for PSS. Part I of the PSS Case A
pig article discussed lab testing. The parents of a PSS pig
that dies may also be lab tested, but it is already known that
both had to be carriers to produce offspring with 2 copies of
the PSS gene.
Duchess Fund: If
both parents test negative for PSS by a DNA test, can we
assume that all babies are PSS free?
Dr. Lawhorn: Yes!
Duchess Fund: Do
carriers demonstrate PSS signs after stress?
Dr. Lawhorn: No. Even PSS swine may not demonstrate signs
of malignant hyperthermia after mild stress. For example, many
domestic swine that are known to have PSS have been
successfully transported to slaughter and not shown outward
signs of PSS. However, both PSS and carrier swine are
predisposed to exhibit the undesirable meat quality of PSE
pork. It is noteworthy that PSE can occur in pork from normal
pigs that have been overly fatigued during an extended transit
time to slaughter. This means that the PSS mutant gene is not
the only cause of PSE pork and shows how a stress, such as
muscle fatigue, can affect even normal pigs.
Duchess Fund: Are
there outward signs or characteristics that might indicate a
pig is a carrier or has PSS?
Dr. Lawhorn: There are no outward signs for a carrier but
a PSS pig may show signs of becoming stiff-gaited after
exercise or other stress followed by muscle tremors, mouth
breathing and rapid over heating. If the pig dies, rigor
mortis will already be present to some degree. Young pigs may
exhibit mild signs of PSS that worsen as the pig ages and
gains muscle mass.
Duchess Fund: Is a
PSS pig at less risk as he/she ages?
Dr. Lawhorn: As previously discussed, as the weight and
age of the pig increases, the risk of MH and death after
stress increase because there is more muscle mass to
uncontrollably contract and generate excessive body heat and
metabolic disturbances not compatible with life. As a PSS pig
reaches a mature body weight, the risk of stressing out and
dying should remain constant since the genetics of the pig
Duchess Fund: If a
pig has been under anesthesia for a medical procedure and
recovered without incident, can it be assumed that pig is PSS
Dr. Lawhorn: It was discussed previously that younger and
smaller body weight PSS pigs (2 PSS gene copies) easily
survived brief anesthesia with halothane gas even though they
did show increased temperature and muscle stiffening before
being taken off anesthesia. Also remember that the halothane
anesthesia test could not differentiate between normal and
carriers (1 PSS gene copy). Therefore, successfully undergoing
any type of anesthesia (gas, injectable or combinations) does
not mean the PBP is not a carrier. It is even possible that a
young PBP with PSS might successfully undergo anesthesia once
but demonstrate PSS signs and die under anesthesia when older
and heavier. Therefore, successfully undergoing anesthesia,
especially at a young age, is no guarantee that the PBP is not
a carrier or PSS animal.
Duchess Fund: If a
pet pig tests PSS positive and subsequently needs veterinary
care (which may be stressful), can any technique or drug be
used to prevent a PSS episode?
Dr. Lawhorn: To date the need for such intervention has
been extremely uncommon since PSS is extremely rare in pet
pigs like PBPs. However, if a pet pig has been acclimated to
going to the veterinarian’s office even by mock health visits,
there should be less stress on the animal. It must be
emphasized that any stress on a PSS pig of any breed may
result in an acute PSS episode and sudden death. For this
reason pretreatment at home with a drug such as dantrolene
sodium could prevent a PSS episode. Dantrolene sodium is
muscle relaxant used to prevent MH in humans. It is available
to physicians under the trade names Dantrium(r), Dantrolen(r),
Dantamacrin(r) and Danlene(r). Dantrolene sodium is an
expensive drug only available by a veterinary prescription.
The client’s veterinarian would have to make a PSS diagnosis
before it would be practical for the veterinarian to prescribe
such a drug (dantrolene is not normally kept by most
veterinarians since it is expensive and rarely needed).
Duchess Fund: Can
PSS skip a generation or more?
Dr. Lawhorn: To answer this question it is important to
understand that normal sire and normal dam matings produce
only normal pigs and no PSS carriers (1 PSS gene copy) or PSS
pigs (2 copies of PSS gene) . A normal sire mating to a PSS
carrier dam (or vice versa) produces 50% PSS carrier offspring
and 50 % normal offspring. As long as PSS carrier offspring
kept as breeders are never mated to another PSS carrier, no
PSS offspring will ever occur; so many generations could be
"skipped" before PSS pigs were produced. However,
the only thing that determines whether PSS pigs are produced
is strictly genetics, not number of generations.
Duchess Fund: What
impact does inbreeding have on PSS and potbellied pigs?
Dr. Lawhorn: To put this question into perspective,
consider that only one lab-confirmed fatal PSS Case A (2000)
and one possible nonfatal case of PSS (Journal American
Veterinary Medical Association, 1993) have been reported since
potbellied pigs (PBPs) have been introduced into the U.S. Case
A (fatal PSS PBP) means the its parents are PSS carriers and
one or both of the grandparents were PSS carriers and so on.
Since not many PBPs were originally introduced into the U.S.,
the gene pool that established PBPs as U.S. pets is very
small. When breeding within a very small gene pool, inbreeding
cannot be avoided unless new genetics is introduced. Since
this original gene pool has probably not been expanded, the
PSS mutation must have been passed down from generation to
generation until PSS carrier parents were finally mated and
produced offspring that were PSS PBPs. Therefore it could be
argued that the breeding within the narrow gene pool has
already been the cause of PSS in PBPs. Since DNA testing to
distinguish normal, carrier and PSS swine has only been
readily available since about 1993, cases of sudden death in
PBPs from PSS may have gone undiagnosed until recently. If PSS
cases or carriers in PBPs continue to be lab-confirmed by DNA
testing, it seems that breeding for years within a narrow gene
pool has contributed to the problem.
O’Brien PJ and Ball RO.
Porcine Stress Syndrome. In: Straw BE, D’Allaire S, Mengeling
WL, et al, eds, Diseases of Swine. Eighth edition, Ames: Iowa
State University Press, 1998; 757-775.
Viral Genetics and
Evolution. In: Fenner F, Buchanan PA, Gibbs, EPJ, et al, eds,
Veterinary Virology. Orlando: Academic Press, 1987; 89-116.
Micromedex (R) Health
Care Series Integrated Index, Vol. 106, expires 11/2000,
We thank Dr. Lawhorn
for his time and effort in helping our readers understand this
A new diagnostic
technique has just become available and is being offered by
GeneScreen. In the past, fresh blood or fresh tissue from a
live pig had to be sent to a lab for DNA testing in order to
confirm PSS. Now, however, tissue and/or bones from a deceased
pig can be sent to GeneScreen for DNA testing. We asked DNA
Technologist, Jarrod Waton with GeneScreen to elaborate on
this new technique for our readers, which follows:
Jarrod Watson, DNA
2600 Stemmons Fwy. #133
Dallas, TX 75207
(214) 631-8152 or toll free (800) 752-2774
The test that
GeneScreen, Inc. uses to detect the presence of the Porcine
Stress Syndrome (PSS) gene requires DNA from the pig. DNA is
in every cell of the body. Generally this test is performed
using DNA isolated from the pig’s blood. GeneScreen, Inc.
utilizes blood stain cards requiring significantly less blood,
primarily to decrease cost for the pig owner. In addition, the
same test can be run using various postmortem body tissue
samples. Some of these tissue samples include skin, internal
hair (including the follicle), given proper quantities of the
particular tissue. However, many of the methods used for the
extraction of DNA from these tissues do incur additional
costs. If you are wishing to have a test performed using these
tissues, be sure to call and ask about feasibility and
We thank Mr. Watson for
his time and effort to provide us with information on this
As we outlined in
Part I, here are the instructions if you would like to have
your pig tested for PSS.
- Contact Ed Kenney at
Swinetics, phone 877-440-0894 who will register you free
- After registration
with Swinetics, contact Jarrod Watson at GeneScreen, phone
800-752-2774 and he will send you the material for the
card test which consists of a few drops of your pigs’
blood placed on a card and mailed to their lab. Directions
will be given for tissue and/or bone samples also as well
as any cost differences.
Swinetics first will reduce the cost of this test. Please
furnish a copy of the test results to your veterinarian and
The Duchess Fund
so we can document them.
Due to additional
questions raised concerning Porcine Stress Syndrome, we
are now working on Part III. If you have any question(s),
please submit to
us so we can include yours as well. Remember, there are no
except the ones not asked!
If you need additional
information, please contact us (below).
The Duchess Fund is a
non-profit 50l(c)(3) corporation whose purpose is to enlarge
the amount and enhance the quality of data available to the
individual practitioner relative to the care and needs of
potbellied pigs as long term companion animals. Your donations
make it possible for us to continue our important work and
obtain our goals and accomplish our objectives.
The Duchess Fund
408 – 14th St. S.W.
Ruskin, FL 33570
2000 The Duchess Fund All Rights Reserved
A COPY OF THE OFFICIAL
REGISTRATION AND FINANCIAL INFORMATION MAY BE OBTAINED FROM
THE DIVISION OF CONSUMER SERVICES BY CALLING TOLL FREE WITHIN
THE STATE. REGISTRATION DOES NOT IMPLY ENDORSEMENT, APPROVAL,
OR RECOMMENDATION BY THE STATE. THE NUMBER FOR THE DIVISION OF
CONSUMER SERVICES IN FLORIDA IS 800-435-7352. Registration
#SC-11271 The Duchess Fund does not utilize any professional
solicitors. 100% of contributions go directly to The Duchess
Precision in Control of Intramuscular Injectable
Anesthetics in Swine by D. Bruce Lawhorn
In swine destined for human consumption,
veterinarians correctly stress that the ham
muscles are not to be used for injection because
any lesions in this area will reduce the value of
a major portion of the pork carcass. The neck
muscles and subcutaneous areas behind the ears
and the lose skin in the axillary spaces of the
front or hind limbs are excellent sites for
antibiotic and deworming injections and
vaccinations (always follow product label
instructions for injection site). However,
intramuscular injection of tranquilizers such as
xylazine and anesthetics such as TelazolR and
ketamine have the most predictable onset of
action, duration of anesthesia and recovery time
when injected into the ham muscles. Tranquilizer
and/or anesthetic injection using the neck
muscles in obese potbellied pigs or even lean
show swine seem to be more poorly absorbed and
often necessitate repeat administration to
achieve an acceptable plane of anesthesia or
restraint, and makes the recovery time prolonged.
The worst scenario is lack of anesthetic control
when previously injected drugs suddenly exert
their action and cause the plane of anesthesia to
become too deep. At this point, resuscitation may
In addition, every possible advantage should be
sought before anesthetizing Sus scrofa. Fast the
animal for 12 to 24 hours and withhold water 4
hours prior to the procedure. Aspiration
pneumonia in non-intubated pigs (intubation is
difficult in pigs) is a real risk Preanesthetic
injection of atropine (0.05 mg/kg IM) has been
recommended to reduce salivation induced by
inhalant anesthetics such as halothane. It has
been reported that xylazine prevents salivation
induced by TelazolR or ketamine. Clinical
experience with xylazine and TelazolR anesthesia
in swine substantiates this reported claim.
Perform a physical exam to rule out obvious
problems such as pneumonia, that significantly
increase the odds for anesthetic death. Also
obtain a history that includes tolerance to
exercise and on the pig’s arrival to the clinic
walk it around to observe for signs of
respiratory distress or muscle tremoring. Pigs
with pneumonia will usually cough after light
exercise. Heavily muscled show pigs may display
signs of Porcine Stress Syndrome (PSS) such as
stiffness, muscle tremors, extremely rapid
elevation of body temperature (PSS also called
malignant hyperthermia), vasodilation and red
blotching of entire skin surface (seen in white
pigs), and mouth breathing when exercise
stressed. The smaller the size of the pig, the
better the chance for recovery from a PSS
episode. This is why the history is so important.
Smaller pigs may have had non-fatal episodes of
PSS that can be described or "hinted
at" by the owner in a thorough history. One
probable nonfatal case of PSS in a potbellied pig
(PBP) under isoflurane gas anesthesia has been
documented, and another PBP case with a fatal
outcome during a routine spay was recently
diagnosed PSS positive and confirmed by a DNA
blood test at Marshfield Laboratory. PSS genes
are inherited in association with heavy muscling,
therefore light muscled breeds, such as the PBP,
are expected to have a low prevalence of this
genetic defect. However, if PSS cases continue to
be reported in PBPs, extensive inbreeding could
be the cause.
Care must be exercised in blood sampling a
suspected PSS pig since any stress such as
restraint may trigger the syndrome and cause
death. Alternatively, the sire and dam may be
blood sampled and tested. If both parents are
carriers (have one PSS gene [heterozygous] ), 25
percent of a litter will carry two mutant genes
and be PSS animals (homozygous recessive), likely
to express PSS signs after stress and die; 50
percent will be carriers and 25 percent will be
normal. If one parent is a carrier and one is
normal, 50 percent of offspring will be carriers
and 50 percent will be normal. Carrier swine do
not express malignant hyperthermia of PSS when
Two labs currently offering the PSS test are
Marshfield Laboratory, 1000 North Oak Avenue,
Marshfield Wisconsin, 54449 (800-222-5835) and
GeneScreen, 2600 Stemmons Freeway, Suite 133,
Dallas, Texas 75207 (800-752-2774). Marshfield
requires at least a 2 ml EDTA blood sample that
is refrigerated and sent overnight with coolent,
but Genescreen uses a testing procedure requiring
only several drops of blood on a card that may be
sent unrefrigerated in an envelope (also will
accept whole blood EDTA samples). Obviously it is
much easier and less stressful to obtain several
drops of blood from a needle prick of ear vein or
other area than to collect larger quantities.
However, remember that any amount of stress on a
PSS pig may cause expression of the syndrome and
possible death. Both test are expensive but
registration (registration instructions available
from either lab) slightly decreases the cost.
Swine recovering from anesthesia seem to take at
least 6 hours to regain adequate thermoregulatory
ability. This means they are susceptible to hypo-
or hyperthermia depending on their recovery
environment. Show swine are commonly anesthetized
in a trailer and transported before completely
recovering from anesthesia. PBPs may be
anesthetized at the client’s home with recovery
observation assigned to the owner. On days with
temperature extremes, swine recovering from
anesthesia are at risk for complications and
death. Animals recovering from anesthesia should
be observed, temperatured and turned at least
once an hour until they are walking around and
alert. This usually takes 2 to 6 hours with IM
anesthetics. Monitoring recovery is best
performed by veterinarians or professional staff
that can recognize hypo- or hyperthermia and
other complications and take appropriate actions.
anesthetics in swine can be safely and
effectively utilized if the previously discussed
practices are considered and implemented to fit
into each practitioners routine of swine
Lawhorn, DVM, MS, Associate Professor and
Extension Veterinarian, Texas Agricultural
Extension Service and Dept. of Large Animal
Medicine and Surgery, College of Veterinary
Medicine, The Texas A&M University System;
Swindle MM. "Anesthetic and Perioperative
Techniques in Swine: An Update," Charles
Spring 1994; Ko JCH, Thurmon JC, Benson GJ, et
al. "Using Telazol-ketamine-xylazine
anesthesia for castration of cryptorchid
pigs," Veterinary Medicine, October 1994,
999-1002; Claxton-Gill MS, Cornick-Seahorn JL,
Gamboa JC, et al. "Suspected Malignant
Hyperthermia Syndrome in a Miniature Pot-Bellied
Pig Anesthetized with Isoflurane," Journal
American Veterinary Medical Association, Vol.
203, No. 10, November 15, 1993, 1434-1436; and
personal communications with Barbara Baker and
Jenny Blaney, The Duchess Fund, Inc.
www.Duchessfund.org, Ruskin, Florida, Sept 2000.
FATAL DISEASE DISCOVERED IN POTBELLIED PIGS
Mehra, Staff Writer, VetCentric.com
Potbellied pig owners may have cause for concern.
Porcine stress syndrome (PSS), a potentially
life-threatening genetic disease, thought only to
affect commercial swine, has recently been found
in the genes of at least one potbellied pig.
PSS is a syndrome of acute death, and signs may
include progressive breathing problems, tremors
and stiffness, and high body temperature. The
disease causes incorrect calcium transport to
muscles, which creates an excess of lactic acid
as well as a high temperature. Both symptoms can
be fatal. In livestock pigs, the disease usually
is onset after transportation, and due to
fighting, exercise, and even a hot climate.
One potbellied pig has already died from the
disease and another pig, suspected of dying from
PSS as well, is being tested. According to the
Duchess Fund, an organization that provides
medical information about potbellied pigs to the
public, the first pig, known as "Case
A," died during a spay procedure and a DNA
test revealed the pig had PSS. "Case B"
also died during a spay, but no fresh blood was
available so the parents are being tested. The
mother was negative for PSS, or malignant
hyperthermia as it is also called, and the test
results of the father pig are pending, said
Barbara Baker of the Duchess Fund.
PSS has long been known as a genetic disease in
commercial swine that is promoted by overgrown
muscles and stress. As of yet, there is no way of
knowing if Case A was an isolated incident or if
the PSS gene is widespread in potbellied pigs.
"They’ve bred it out of commercial
swine," Ms. Baker said. In fact, commercial
breeders were able to breed the gene out of the
pigs fairly easily, added Barbara Straw, DVM,
"It’s controlled at a single
gene," Dr. Straw explained. "This gene
is associated with heavy muscling."
Potbellied pigs are often kept as companion
animals and how the disease got into their gene
pool so far is a mystery. The pigs are not bred
for food and so their muscles are not overly
developed. PSS can be brought on, however, by
anesthesia, which is what happened in Case A.
Potbellied pig owners may be concerned because if
their pig has the PSS gene, it might die from a
simple procedure requiring the use of anesthesia,
such as a spay or tusk trimming, Ms. Baker said.
If a pig was known to have PSS, Ms. Baker said,
"you would certainly want to limit the
procedures down." For example, a pig with
PSS might not have its tusks trimmed as often as
a pig without the gene.
A drug called Dantrolene can be used to stop a
PSS attack, Ms. Baker, said but few veterinarians
carry it since PSS had never been known to affect
Dr. Straw said she doesn’t think the disease
is widespread among potbellied pigs; if it were,
more pets would have died during spays.
It should be just as easy to breed the gene out
of potbellied pigs as it was to remove the gene
from the commercial pigs’ pool, but since
only one case of PSS has been confirmed, this may
not even be necessary, Dr. Straw said.
"It may be that very few carry this
trait," she said. Even the pigs that do have
the gene do not always get PSS. "Most of
them get along without having an episode."
For more information:
To find out if your potbellied pig has the PSS
gene, you can order a special test kit from
GeneScreen, a genetic testing laboratory. The kit
costs $33 (or $25 if you pre-register with
Swinetics at (877)-440-0894) and contains
instructions and a blood absorbent card. Once the
card containing a drop of the pig’s blood is
mailed back, it takes five days to get the
PIG DISEASE by: Dr. John Carr,
B.V.S.C., PhD, DPM, MRCVS Garth Veterinary Group.
Many of you may have heard rumors of a new
disease which has been seen in the UK
particularly since the summer. The full name for
this disease is Post-weaning Multisystemic
Wasting Syndrome. The problem currently is mainly
confined in Anglia and the Midlands, however, as
the disease has no specific causal agent, its
precise means of spread can not be determined. In
general this disease should pose little risk to
the pet pig population however, it is better to
be advised of its existence.
name suggests the disease’s principle sign is
severe rapid weight loss in young pigs of 6-15
weeks of age. Pigs also show respiratory
distress, pale skin and occasionally scour. The
disease is a syndrome and this means that we do
not know exactly what causes it. There is some
evidence from Europe e.g. France and Spain where
it has been causing problems since 1997 that a
Porcine Circovirus type 2 (PCV-2) is at least
disease appears to infect piglets before 4 weeks
of age, and then at least 5 weeks later starts to
cause the wasting symptoms. The disease can also
spread from the wasting pigs to other in contact
pigs, with an incubation period of some 4 weeks
before symptoms are seen.
are unlucky enough to have a case please contact
your vet. If the pig dies, and mortality can be
quite high, for your vets information, the post
mortem findings suggestive of the syndrome are
rubbery lungs with interlobular oedema giving a
mosaic pattern to the external surface of the
lung. Lymph nodes are massively enlarged
indicating that at least part of the disease is
due to a dysfunctional immune system. Gastric
ulcers are often identified. There are tests on
tissues which will confirm the PCV-2 presence.
we have not come across any really effective
treatment. In cases the best thing to do is to
keep the pigs well bedded down to keep them warm
without restricting ventilation. Soluble
antibiotics seem most effective rather than using
injectables as this only causes more stress so
making it more difficult for the pig to fight the
primary viral disease. Routine vitamins in the
drinking water help the pigs to fight off the
viral challenge and broad spectrum in feed
antibiotics help prevent secondary infections.
spread predominantly by pig movements therefore
the risks to pet pigs are minimal assuming basic
health precautions are adhered to. In particular
it would be wise to isolate all incoming stock
for at least 3 weeks off farm if possible and
contact the supplier to see there have been no
further disease problems before moving them onto
your unit. Use different clothing and boots when
feeding and cleaning out the new arrivals.
Discuss with the breeder that there are no PMWS
problems. Report any suspicious problems to your
Used With Permission From The Potbellied Pig
by: Jenny Blaney
It’s spring. I can
tell because the calls about Dippity Pig are
coming in. The medical term for Dippity is
Erythema Multiforme. Literally translated it
means: a superficial reddening of the skin,
usually in patches, that takes many forms.
Personally, I like "Dippity Pig"
Dippity can vary in character and severity from
pig to pig, there are certain definite symptoms.
These include, but not necessarily all at once:
sensitivity to being touched around the
back end of the pig sometimes to the
point that the pig squeals when touched
"hunkered-down" stance with the
tail tucked between the back legs and
clamped to the body
of and/or inability to use the back legs
to the point of falling down
symptoms may or may not be accompanied by moist,
red areas appearing over the rump region and
extending halfway up the back toward the head.
These moist areas sometimes turn into actual
lesions that can ooze serum or blood. They
usually run from side to side, not head to tail.
George, D.V.M. from the University of California
at Davis, describes Dippity as:
clinical signs include squealing and inability to
walk without falling down in the rear limbs.
Affected pigs suddenly howl painfully, and fall
with the rear limbs extended backward, and the
back arched. They may pull themselves forward
with the fore limbs while keeping the rear limbs
extended behind them. The skin over the lumbar
area is extremely painful, and the pig resists
vigorously whenever the back is touched lightly.
Severe responses can be evoked by blowing on the
back. The skin thickens over twelve hours, and
begins weeping. This forms an oval wet patch over
the lumbar area measuring 5 by 10 cm."
of symptoms of Dippity is often quite sudden. The
weakness and sensitivity in the back legs can
occur in a matter of hours. A perfectly normal
pig can be incapacitated three hours later. Any
skin eruptions or lesions can occur in a matter
of minutes. Depending on the pain threshold of
the pig and the severity of the case, the animal
ends up anywhere from uncomfortable to screaming
primary cause of Dippity appears to be stress. It
is not clear whether the stress is external or
internal in nature, or whether it can be
self-induced. External stress could include a pig
show, a trip to the vet, the introduction of a
new pig or owner, a violent thunderstorm or a
sudden deviation in normal routine.
appears to be some correlation between Dippity
and exposure to the sun. A friend of mine
acquired ten, white, commercial pigs who were
about ten weeks old. They had been in a total
confinement system, therefore, had never been out
in the sun. Upon their release into the great
outdoors, these white pigs all developed the
"dipping" and "squealing"
symptoms of Dippity, without the lesions. Was
this just a case of severe sunburn or Dippity
stress could mean an inappropriate diet or a
change in diet, inadequate water supply, a sudden
drastic change in body temperature due either to
illness or climate, even the onset of a
particularly hard heat cycle for the female pig.
Often the triggering of a Dippity episode can be
traced back to an unusual, recent event in the
no treatment for Dippity, nor is there any
preventive medication available at this time
since the exact causes have not been determined.
Topical creams or sprays can encourage healing of
the sores and lesions. Injectable drugs can be
used to alleviate discomfort or pain. However,
once Dippity occurs, no drugs will prevent it
from running its course. The onset of Dippity is
quite spontaneous. Duration of symptoms can be
anywhere from 24-72 hours. Complete recovery is
just as spontaneous and mysterious. Spring and
summer seem to be the most common times of year
for Dippity to occur. More often than not it is
younger pigs who are affected – that is pigs
under two years of age.
important thing you can do for your piggies if
Dippity strikes, is to immediately reduce stress,
both internal and external. Confine your pig in a
suitable temperature for the time of year. A
quiet, dark place does a lot to calm your pig.
Low music helps to soothe also. Keep your pig
well hydrated during the episode. Reassure and
comfort your pig often, but complete rest is a
must. Prevention of sunburn can be accomplished
by using a sun screen on your pig. If lesions are
present, liquid vitamin E or aloe vera gel are
soothing and healing. Some vets prescribe topical
1% hydrocortisone cream. Consult your
veterinarian as to the appropriateness of drugs
to alleviate discomfort or pain.
can occur as a single, one-time event, or a pig
can suffer multiple attacks. Seldom does it occur
in older pigs, even though they may have been
affected as younger kids. Perhaps they outgrow
it. In seven years, I have never heard of any
lasting ill effects from this mysterious
who have had Dippity more than once, there is a
check list available to help determine the causes
and possibly provide preventive measure. For
further information, contact Jenny Blaney.
ABOUT MANGE? by: Jenny Blaney
Mange is a
skin disease that is caused by mites, small
insect-like parasites, almost invisible to the
naked eye. Each species of domesticated animal
has it’s own species of mange mites; and, with
the exception of the sarcoptic mites, the mites
from one species of animals cannot live normally
on a different species. However, the sarcoptic
mites are transmissible from one class of animals
to another. The spread of mange is most often
through physical contact, such as a pig touching
another pig. Bedding that holds moisture (such as
straw) and cold temperatures makes it easier for
the mite to survive off the pig. The sarcoptic
form of mange is the most damaging, causing
severe skin irritation including itching,
lesions, and crusting, as well as unthriftiness.
The female mite attacks her host laying eggs for
about two weeks. The eggs are hatched and the
mites reach maturity in another two weeks.
Therefore, a new generation of mites can be
produced every fifteen days. This high rate of
proliferation makes the eradication of mange
first identified as a pest in pigs 140 years ago.
It continues to this day to be a challenge to
veterinarians and remains a costly proposition in
commercial pig operations. Don’t assume that
because your potbelly is a pet in the house that
the following information does not apply to your
situation. The sarcoptes scabies var. suis is
just as content to munch on your potbelly as a
of mange can be anywhere from sub clinical to
very subtle to obvious. Potbellies with sub
clinical mange could be regarded as
"carriers" with no visible signs of the
parasite. These are the most difficult cases to
spot. They do not rub or scratch nor do they have
any discoloration of the skin. There are no
"flakes" or dandruff. There are no
lesions. However, when sub clinical potbellies
are subjected to stress such as traveling to the
vet or a show, a sudden cold or hot change in the
weather, a new member added to (or subtracted
from) a household, mange can spontaneously erupt.
A gilt coming into their first heat can suddenly
break out with mange. Symptoms of mange can be
very subtle, but left untreated will develop into
more obvious signs. Symptoms characteristic of
mange infestation are as follows:
pigs’s skin is dry and scaly, like
"dandruff" (potbellies are
known for their dry skin making it even
more difficult to differentiate between
mange and a normal dry skin condition.)
pig begins to rub against objects – a
black pig will leave white
"tracks" on the body where it
has rubbed against furniture, etc.
bumps and/or scabs appear just under the
surface of the skin most often found
behind the ears, under the front legs and
on the chest, between the back legs and
on the ankles just about the hard hoof.
These bumps become more prevalent
anywhere the skin is thin or moist or
same moist areas take on an orange cast
in color, more easily seen on pigs with
white skin, but present on black pigs as
well. The orange color will wash off only
to reappear in two or three days.
begin to exude excessive amounts of
reddish-brown debris. Ears sometimes have
a bad smell.
have the same reddish-brown, crusty
matter in the corners and sometimes on
begin to tear, sometimes to the point of
leaving tear "tracks" down the
face. The pig looks like he is crying.
A pig may
have all of the above symptoms without having
started to scratch or rub. A pig may rub or
scratch a lot with only one or two of the above
symptoms. Some pigs just have filthy ears and
eyes that "cry" but no other symptoms.
As with most syndromes, some pigs seem to have a
higher resistance threshold while other pigs are
super sensitive to mange infestation.
untreated, a pig with some or all of the symptoms
above will develop a "chronic"
condition that is classic and easy to recognize.
Aside form the stated indicators of mange, there
are some additional signs to look for:
scabby, thickened skin
thin and/or actual hair loss
skin becomes dark gray
cast is more prevalent
top of the back between the shoulder
blades will be a greasy patch due to
constant localized irritation.
chronic and/or obvious cases of mange are more
prone to being treated, I would like to focus
further on the less obvious sub clinical
potbellies are vaccinated and wormed twice a year
as part of their normal medical management
routine. In addition many owners worm in-between
those visits to the veterinarian. A pre-existing
case of mange is probably kept somewhat under
control in these cases, although it is never
really eradicated. Therefore, lingering subtle
symptoms are present but not always recognized.
Skin and hair coat damage from mange mites is
gradual and may be misinterpreted as due to
inadequate diet and/or vitamins.
I have been told of a change in temperament of
the pig. The pig may become a little more
lethargic, less "sweet," cranky and
less tolerant of being handled. Since worming is
being done at least twice a year and there are no
obvious symptoms, mange is seldom considered the
culprit. In almost all cases the dirty ears are
the big tip-off. Proper treatments for mange,
even without a confirmed diagnosis almost always
results in improvement in general condition,
appearance and temperament of the pig.
the life cycle of the mange mite helps to tailor
treatments accordingly in order to kill the mites
continuously as more eggs hatch, thereby
effectively breaking up the cycle. Since mites
eventually find their way to the pig’s head,
especially the ears, I have found it necessary to
treat the ears specifically and in conjunction
with the rest of the pig’s body. The canals in
the ears are dark and moist and serve as a
perfect protected environment for the mange mite.
The ear tissue is very thin which makes it easy
to penetrate. Often the ears will exude excessive
amounts of dark red-brown debris. Similar debris
is often found in the corners of the eyes and in
any wrinkles about the face. Alex Hogg, DVM,
University of Nebraska, shared a diagnostic
approach with me:
deeply in the ear of the pig with a
curette or small melon baller. Get some
skin and debris – sometimes you need to
see a little blood to be sure you are
all the debris in a small, clear, plastic
debris with one teaspoon baby oil.
petri dish at 37°c (body temperature)
mites will come out of the debris, skin,
etc. and can be observed swimming in the
baby oil the next day.
under a 10 X dissecting microscope to
personal feeling is that mites are able to
survive for a time in the debris in the ears,
rather than in the ear tissue itself. The ear is
the only place where debris can build up
significantly without dropping off the body. By
the time the mites have exhausted the debris and
need to tunnel back into the skin, any mange
treatment given the pig has worn off. If the ears
are treated separately and simultaneously with
the rest of the protocol, the whole pig clears up
faster. I have had very good results with the
a mix of ½ hydrogen peroxide and ½
isopropyl alcohol and put in a small
plastic bottle with a tapered snout on
the end. Warm solution before each use –
the pig will object less.
warmed solution directly into each ear.
Try to rub and massage the ears to work
the solution down deep into the ears.
solution will help loosen any large
pieces of debris that may be lodged where
you can’t see. The pig will shake its
head which will also help free up chunks
to clean as much discolored debris out of
each ear. Never go deeper into the ear
than you can see.
recommended number of drops of
Tresaderm® into each ear and massage.
This is a dog/cat ear preparation for ear
mites. It also contains an antibiotic
that reduces inflammation of the
sensitive ear tissue.
Note: I didn’t say any of this
would be easy….I’m just saying it works!
this procedure every other day for five
treatments. Always clean the ears first so that
the medication can get down deep enough to work.
After five treatments, check ears weekly for
signs of re-infestation. If needed repeat above
steps for five more treatments.
various treatment protocols for mange on the
body, depending on the severity of infestation.
Injectables remain the drugs of choice since they
can reach all parts of the pig, except perhaps
the ears for reasons previously stated. The
following, as well as the earlier described ear
treatment, is based on my personal experience. As
with any health issue concerning your potbelly,
always consult with your veterinarian and follow
administering any medication to your potbelly you
need an accurate weight. That doesn’t mean a
"guesstimate". That means actually
weigh your pig. For any drug to be successful,
the dosage must be accurate.
preventive maintenance regimen can be achieved by
using a pour-on topical, an oral, or an
injectable preparation designed to kill both
internal and external parasites. Pour-ons work
best on pigs with a fairly heavy hair coat since
the medication needs the hair shaft to penetrate
into the body. Frequent close examination of the
pig’s skin and ears should inform you of the
presence or absence of mange. If no signs of
mange are evident, periodic treatment according
to your veterinarians’ recommendations, can keep
your pig mange free.
Fall seem to be the two most common times of year
when manage mites are prevalent. However,
depending on climate and immediate environment,
infestation can occur any times of the year.
found the following to be effective:
Pour-On for Cattle and Ivomec® Injection for
Cattle and Swine are ivermectin-based drugs.
Ivomec® is the Merial Ltd. registered trademark
for ivermectin. Another injectable drug option is
Dectomax®. This is the registered trademark of
Pfizer Animal Health for the drug called
doramectin. Dectomax® lasts eighteen days in the
pig’s system. It is virtually pain free.
Dectomax® may prove to be a good alternative to
Ivomec® for this reason. Seek the advise of your
veterinarian as to which product will produce the
best result and recommenced treatment regimen.
occasional out-break brought on by exposure to
another pig or simply environmental conditions,
topical or injectable preparations can be quite
effective in stopping the mite in its tracks
provided treatment commences early on. Use
product and protocol recommended by your vet but
increase the number of treatments to at least
three and possibly four. Treatments must be given
at proper intervals. In addition, the ears should
be treated at the same time following the
procedure outlined. If these protocols seem like
"overkill", bear in mind that it is
worth the expense and time spent, rather than
dealing with re-infestation.
experience, when mange becomes a chronic
condition in pig, the luxury of a topical
preparation is no longer an option. A more
aggressive approach will be needed. The most
effective treatment is going to be the injection
and it will ultimately be the least stressful for
the pig. Coupled with the Tresaderm® in the
ears, the injections will need to be timed to
interrupt the life cycle of the mite. The whole
treatment protocol should be structured around
the level of infestation, the possible exposure
to re-infestation (as in multi-pig situation),
and the pig’s general environment such as
bedding, housing, etc.
chronic mange, my protocol is:
pig(s) in question providing a clean, dry
space either indoors or outdoors with
with first injection of an appropriate
dose level based on accurate weight.
ear treatment as previously described
simultaneously with the injection.
second dose 10 days later.
ear treatments with Tresaderm®.
it is not necessary to treat the bedding,
it is advisable to change the bedding at
the same time each injection is given.
third injection 10 days later.
upon each pig’s response, a fourth
injection may be needed.
to check ears frequently for any signs of
in severe and/or long-standing cases of mange, I
have encountered an additional problem. Due to
self-mutilation by constantly scratching and
rubbing, some pigs can break open the skin enough
to set off a positive gram staph infection which
further complicates their condition. This
infection impedes healing, promotes further hair
loss, and while mites may no longer be present,
the over-all condition of the pig does not
improve. In these cases antibiotic therapy has
been necessary. Continue to examine the pig even
after mange treatments are complete. Appreciable
improvement in skin, hair coat, eyes, ears and
even temperament can take as long as thirty days.
that mange is highly contagious from pig-to-pig
through pig-to-pig physical contact. If one
animal in your group of pigs is showing signs of
mite infestation, the chances are others can or
will be plagued as well. In multiple pig
situations, a preventive mange control program
should be followed. Treat all pigs on premise
simultaneously at least biannually. When
considering any mange prevention or control
program, check with your veterinarian as to
appropriate drug, dosage, and administration
based on your individual needs.
mange mite can be a tough critter to irradiate.
The best ammunition against infestation is as
frequent skin and ear checks.
- Get a
timely diagnosis by your veterinarian of
the presence of mites.
a good understanding of the life cycle of
an accurate weight of your pig.
with your veterinarian on appropriate
is no short cut – all medication
directions must be followed. Subsequent
treatments must be given at proper
intervals in order to break the life
cycle of the mite.
ears simultaneously with Tresaderm®.
can conquer the mange mite dilemma before another
140 years go by! After all, we humans are WAY
more mighty than that pesky, microscopic mite!
URINARY FUNCTION by: Jenny Blaney
owner, know your potbellied pig better than
anyone. You, the owner, are in a unique position
to observe your pig on a daily basis. It follows
that maintaining your pig in a healthy state is
going to be up to you. Consistent management
practices will help you to quickly pick up on any
deviation from your pig’s normal affect and
behavior. Your ability to notice changes will
ultimately be proportionate to the depth of your
relationship with your pet. This ability in turn
will help ensure that your pig lives as long and
happy a life as possible. There are some
guidelines to be aware of, as well as tools
available to you to help accomplish this goal.
veterinarian can tell much about the overall
health of your piggy by examining a sample of
urine. This is a relatively inexpensive
diagnostic tool that can be used to monitor
health over the life of your pig. Among other
tings your veterinarian can check the urine for:
Ph level, triple phosphate crystals, calcium
phosphate crystals, protein, blood, pus and
sugar. Bi-annual urine examinations over the life
of your pig will provide valuable information on
overall condition, nutrition, assimilation,
metabolic capabilities and aging. Your
veterinarian will be better able to head off a
potential problem before it becomes a serious
a urine sample from your pig is not as difficult
as it may sound. As with any new activity you try
with your pig, it takes some preparation for
forethought. You know your pig’s voiding routine
better than anyone. There are sterile packaged
kits (for people) you can obtain from your local
pharmacy that are appropriate and convenient.
Follow the directions included in the package to
avoid contamination of the sample. (Any other
container used for collection should be clean and
dry and preferably sterile.) Collection needs to
be done at the same time of day and in the same
manner each time in order to provide consistent
results. The best time for collection is probably
first thing in the morning with a
"mid-stream" catch, avoiding the very
beginning of the urine stream. Discuss the
"art" of collection with your
veterinarian before you start, as to method,
amount and delivery to his/her office. Generally,
if the sample sits after collection for more than
one hour, it needs to be refrigerated. The
fresher the sample is when it reaches the
veterinarian the better. Always collect and
deliver in a consistent manner. Label, date and
enter time of day on the sample.
To aid in
the consistency of findings of each urine sample
submitted, avoid any major diet changes for a few
weeks prior to collection. If you make a diet
change, wait for thirty days after the change
before you collect. This applies to any
medications given along the way as well. Always
follow your veterinarians guidelines concerning
consumption as well as diet affect your pig’s
voiding routine. The first urine sample you
submit to your veterinarian should be based on
what your pig is eating and drinking at present
with no new changes introduced. This will provide
a base for information gathered. Not all pigs are
good water drinkers. If you make any changes to
diet. or fluid consumption, such as adding juices
to drinking water to encourage fluid intake,
check with your veterinarian to see how long you
should wait before taking another sample. Any
changes in diet and fluid intake should be made
one change at a time, with a period of time in
between changes to allow for the body’s adaption
to that change. Again, follow your veterinarian’s
urine for examination twice yearly will make you
more aware of your pig’s voiding routine. You
will begin to notice your pig’s normal behavior
before, during and after voiding. You will be
better prepared to spot changes in behavior
associated with voiding. Pay attention to the
duration of the voiding process, whether it is a
steady stream with some force behind it or just a
trickle. Watch for straining or discomfort
associated while voiding.
results of the first urine sample submitted are
found to be within normal ranges, this is still
valuable information. Those results will provide
a basis for comparing subsequent samples taken
every six months. This continued monitoring of
urine will provide important diagnostic
information on the overall condition of your pig
as the aging process progresses. Again,
consistency in collecting and submitting the
sample is vital to obtaining accurate results.
one simple exercise that you the owner can do
between urine collections. Periodically, while
your pig is voiding, lay a section of white paper
towel down to fully absorb the urine as it is
voided. (Place the paper towel on the ground, in
the litter box, wherever the pig is urinating.)
Then take that piece of paper towel and lay it on
any non-porous surface to dry naturally. After it
has dried thoroughly, check that surface to see
if the dried urine has left any cloudy, shinny,
or white residue. Also examine the paper towel
itself for any discoloration of the urine. If
anything unusual is noted, collect a urine sample
as previously described and submit to your
veterinarian for examination.
owner, can play a vital role in monitoring and
maintaining the health of your potbellied pig.
Three of the most important things you an do to
make your potbellied pig experience a success
and cultivate an in-depth
relationship with your pig.
your management practices as
consistent as possible.
and cultivate a mutually satisfying
working relationship with your