CAE , Caprine
arthritis-encephalitis virus and What it Means to You
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By Gail Bowman |
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My
husband, David, and I started raising Boer goats in 1994 when we saw an
advertisement for Boer meat goats in a magazine. We had bought
two dairy goats the year before, fallen totally in love with them. We
wanted more goats, but not more milk. So we mortgaged our house and
flew to California to bring home our first pair of Boer goat kids. What
an awful experience! They were both sick! They had staph
infections, lice, chlamydia, and the little girl was pregnant at four months
old! Argh! Well, we were in an instant legal battle which
taught us a lot about goat diseases and the value of knowing your breeder!
After that, we found a good veterinarian to teach us how to test our
own goats, and what to test for. Our ranch is now CAE, CL and Johne's
negative, and has been for over three years. We test for disease twice
a year, and are very serious about the results. |
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When
I tried to find a dairy ranch in my area that tested for any diseases, especially
CAE since I live in a high incidence CAE area, I met with surprising resistance
and even anger from the local dairy goat raisers. I had people tell
me that, "CAE is impossible to get rid of, so why make waves?",
and "CAE is just a phantom disease with no real evidence that it exists."
I even had hate mail and nasty phone calls! Well, wouldn't you
know that that kind of resistance just made me more determined? I
finally did find a ranch that had been testing for CAE for 3 years, and
I bought my dairy base for cross breeding from them. |
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Now,
four kidding seasons after that first experience, we have met and visited
many of the top breeders in the United States and Canada. I am the
coordinator for the International Boer Goat Association for the Northwestern
United States. We have done extensive research on, and have a good
understanding of, Boer blood lines and breeding practices. We are
very excited about our crop of beautiful kids this year! Our kids
have the advantage of a carefully designed feeding program, a disease free
environment, and the best spectrum of genetics available! I guess
that just goes to show that good can come from the most unfortunate of circumstances! |
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Please
allow me to share with you some of the new research I have discovered on
CAE. It is not a phantom disease! It is easily understood and
makes perfect sense. Why would any breeder want to ignore a disease
that will cut down on their production and can be easily controlled? Now,
I know that is not reasonable if you have 2000 meat goats. Who has
time to worm much less test? But most of us have relatively small
breeding operations, or dairy operations, that would benefit by the control
of this disease. |
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CAE
or CAEV (Caprine arthritis-encephalitis
virus) is a common disease of goats that is prevalent worldwide. In
the United States, prevalence as high as 81% has been reported for goat
herds. According to a recent study by J. D. Rowe, DVM, "Infection
most commonly occurs when the virus is present in colostrum or milk that
is ingested. However, prolonged contact, particularly in high-density
goat populations, also results in significant transmission." (5
p. 35) Not all CAEV infections in kids can be explained by ingestion
of affected colostrum or milk. Up to 10% of kids from positive
dams, who were removed from their mothers at birth, have been reported
to show infection. In these cases, infection must have occurred in
one of four ways: 1. in-utero transmission, 2. transmission
from the dam by vaginal contact, 3. accidental ingestion of infected
colostrum, 4. transmission from the dam by exposure to saliva or respiratory
secretions during licking. |
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CAEV
infection may not be serologically testable for months or years, and some
infected animals, who can transmit the disease, may never show clinical
symptoms. Symptoms include a progressive rear leg weakness and/or
paralysis in kids 2 to 6 months of age, chronic arthritis (most frequently,
but not solely, of the knee joint) in adults, inflammation of the mammary
gland, lung, and nervous system. Nervous system involvement may include
blindness, head tilts, and facial nerve paresis. Mammary involvement
results in "udder edema" or "hard udder" where the entire
udder becomes hard and warm within the first few hours after kidding, resulting
in the kids going hungry. (11) (This is not to be confused with the doe
that has so much milk at kidding that she needs to be milked in addition
to nursing her kids.) Lung involvement results in chronic pneumonia. |
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In
a milking herd, shared milking machines, milk contaminated hands or towels,
etc. will significantly increase the risk of spreading the disease. In
a meat herd, transmission can occur via needles, tattooing instruments or
dehorning equipment. Also cited by P. L. Greenwood as possible
avenues of infection, in high density herds that are endemically infected,
are head butting to the point of drawing blood, eye-licking, biting, snorting
and coughing, and urinating too near another goat's face.(15) In addition,
according to Rowe and East, sexual contact has been researched with some
definite indications that the risk of infection in the exchange of saliva,
estrus mucus, urine, semen and nasal secretions, is possible. (5 p. 41) |
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The
period of time between exposure to CAEV and development of detectable (testable)
antibody levels has been estimated, by researchers, at between 3 weeks to
8 months after exposure to the disease.(16)(17)(18) Many ranches have
reported conversion from negative test results to positive test results
of goats as old as five years of age, although conversion seems to be most
prevalent between 1 and 2 years of age. Researchers attribute conversions
later than two years of age to some lateral exposure to the disease as discussed
in the last paragraph. |
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The
following steps are recommended to prevent CAEV transmission: 1. Immediately
remove the kids from their dams at birth (with the sack intact until the
kid is out of its mother's body, if possible), being careful to prevent
the does from licking their kids. Then take the kid inside and wash
it in warm water, in a clean sink. 2. Provide heat treated, artificial
or cow colostrum. Do not pool colostrum from mothers
that might be infected and then feed the pooled colostrum to your isolated
kids! 3. Feed pasteurized or powdered milk. 4. Separate all
possibly infected animals from uninfected animals by a double fence with
at least 10 feet between the fences. Do not use common feeders, waterers
or salt blocks. 5. Milk negative and younger does before milking positive
and older does. 6. When possible, breed negative does with negative
bucks. If negative and positive animals are mated, use a single hand-mating
allowing minimal oral contact. 7. Do not share needles, tattooing
equipment or dehorning devices without careful cleaning and sterilization.
8. Test your kids at 6 month intervals starting after the kids are
at least 4 months old. Most breeders suggest testing during times
of stress, such as about 2 to 3 weeks before kidding. There is, however,
some evidence to suggest that a goat with another type of systemic
infection may test with a false positive for CAEV.(5) |
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You
can easily and inexpensively draw your own blood samples for disease testing.
Just use a 3cc syringe and an empty, sterile, red top blood vial.
Get someone to show you how to get the blood, put it in the vial and
Next Day it to a good lab. Here are a few laboratories that may be
able to process your blood sample. If there is not one listed in your area,
try calling the one that is nearest you. They probably know of another
lab that is closer. |
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California
Veterinary Diagnostic Lab System |
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West
Health Sciences Drive |
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University
of California - Davis |
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Davis,
Calif. 95616 |
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(916)752-7577 |
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National
Animal Disease Center |
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PO
Box 70 |
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Ames,
Iowa 50010 |
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Pan
American Veterinary Laboratories |
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3921
Steck Ave |
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Austin,
Texas 78759 |
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(512)794-9657
Fax |
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(800)856-9655 |
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Veterinary
Diagnostic Laboratories |
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University
of Minnesota |
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College
of Veterinary Medicine |
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Carter
and Gortner Aves. |
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St
Paul, Minnesota 55108 |
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Washington
Animal Disease Diagnostic Laboratory |
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College
of Veterinary Medicine |
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Washington
State University |
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PO
Box 2037 |
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College
Station/Bustad Hall, Rm 155-N |
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Pullman,
Washington 99165-2037 |
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(509)335-7424
Fax |
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(509)335-9696 |
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Diagnostic
Laboratory |
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Cornell
University |
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College
of Veterinary Medicine |
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Ithaca,
New York 14853 |
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Footnotes: |
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(5)Rowe,
Joan Dean, and Nancy E. East."Risk Factors for Transmission and Methods
for Control of Caprine Arthritis-Encephalitis Virus Infection" The
Veterinary Clinics of North America Mar 1997 Vol 13 #1 |
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(11)East,
Nancy E. "Diseases of the Udder" The Veterinary Clinics of
North America Nov 1983 Vol 5 Num 3 p.591-600 |
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(15)Greenwood
P.L., R.N. North, and P.D. Kirkland."Prevalence, spread and control
of Caprine Arthritis-Encephalitis Virus in dairy goats in herds in New South
Wales" Aust Vet J 72:341, 1995 |
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(16)Oliver,
R.E, R.A. McNiven, and A.F. Julian, et al."Experimental infection of
sheep and goats with Caprine Arthritis-Encephalitis Virus" NZ Vet 30:158,
1982 |
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(17)Ellis
T.M., H. Carman and W.F. Robinson, et al."The effect of colostrun-derived
antibody on neo-natal transmission of Caprine Arthritis-Encephalitis Virus
infection" Aust Vet J 63:242, 1986 |
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(18)Rimstad
E., N. East, and E. DeRock, et al."Detection of antibody to Caprine
Arthritis-Encephalitis Virus using recombinant gag proteins"
Arch Virol 134:345, 1994 |
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