What are the 3 big causes of EEL that we need to know?
What kind of a critter is Trich?
How is Trich transmitted?
How does this little feller cause economic losses?
Early embryonic losses (infertility)
Long calving interval
Culling/replacement of infected cattle
When are clinical signs seen? What are the clinical signs?
At pregnancy check
Open cows at preg check (50% maybe)
potential pyometras and abortions
may see retained fetal membrane when there is no calf.
Where does Trich colonize in bulls?
prepuce and penile crypts
What is the disposition for these bulls?
Send to slaughter
When are losses seen in cows?
70-90 days of gestation
What follows the EEL's?
2-6 months of infertility
When are cows exposed to Trich?
After a night in aggieville and few too many drinks with a random hook-up with a bull.
Which bulls get it more, young or old? Why?
Old bulls. They have deeper crypts in the prepuce.
That being said, which bulls may clear the infection?
bulls less than 3 years old
How long do older bulls have Trich?
What happens to infected cows?
Clear infection in a few months. (2-22)
May remain infected through pregnancy
Is there any lasting immunity?
There is a vaccine, what is the efficacy in cows? Bulls?
Cows: May shorten calving interval
Bulls: not well researched
When do you give the vaccine?
8wks and 4wks prior to breeding
Which herds have Trich worse, small or large?
Large. There are more bulls in large herds.
How do you diagnose Trich?
What are the samples used for testing?
Bull: smegma (love this word)
Cow: discharge, cervical mucus
When you test, who are you diagnosing?
What is the gold standard for culture testing? What is the production standard?
6 weekly samples
3 weekly samples
We all know that In-Pouch is the test name. How do you handle/ship it?
maintain at 37 degrees C
protect from extremes
don't ship on ice or on cold or hot days
When are the samples read?
every 48h for 5-7 days
When can you freeze the sample?
If you culture it and let the little guys reproduce, then you can freeze and ship it.
What should the producer do with positive bulls?
send positive bulls to slaughter
What do you do as far as testing negative bulls?
retest bulls (3 neg cultures) prior to each breeding season.
test all imported bulls (3 neg cultures)
keep average bull age young
What should a producer do with positive cows?
Cull all open cows
Controlled breeding (he said breading but I think that's when you cook them)
Cull cows with Trich abortions
Cull pyometra cows
maybe vaccinate 8 &4 wks prior to breeding
What do you need to remember about this disease?
IT IS REPORTABLE!
What causes Vibriosis?
Campylobacter fetus ss venerialis
(gram-negative motile rod)
What does this cause?
EEL and irregular-length (longer) cycles
How common is Vibriosis?
very rarely seen
not really seen in the U.S.
How do you test?
There is another Vibriosis pathogen, what is it?
Campylobacter fetus ss fetus
What does this agent cause?
sporadic abortion in herds with no history of infertility
When do the Vibriosis abortions occur?
at any stage but usually in the second or third trimester
What is the transmission of C. fetus fetus?
ORAL, not venereal
How do you prevent?
Vaccination: appears effective
Let's talk about Leptospirosis. What is the biggest thing you need to know?
It is zoonotic
How does infection occur?
through mucous membranes
abraded or water-softened skin
What does it cause?
Later term abortions (the republicans would have a fit!)
causes latent kidney infections
Where does lepto live in the body?
in the kidney and shed in the urine
What is the common source of infection?
urine-contaminated water holes
Lepto has over 250 serovars. Which one do cattle have?
Does Hardjo cause disease in cattle?
not really. There also isn't much immunity to it. It's kind of a pathogen-host agreement.
When does the illness happen?
when it crosses hosts
How well do lepto vaccines work?
work well in non-host species but not in host species
Which serovar is most commonly diagnosed in cattle? (it is the pig serovar)
How are diagnostic tests for Lepto? Why?
not very good for abortion causation.
for L. hardjo, all the cattle have it.
How can you rule out L. pomona?
if no titers in herd are >1:3000.
Can't use titers to rule-in disease
bottom line: if there's no high titers, there is probably not disease.
How do you control Lepto?
through antibodies produced by vx or natural exposure (will clear organism from bloodstream)
Antibodies are serovar specific
If you clear the organism from the bloodstream is the animal free of it?
No. It is still in the body in immuno-protected sites: kidney, brain, repro tract
short duration of immunity
often do not protect against infection, disease or shedding
Vx 2-3 times/month prebreeding
annual re-vx mid-gestation
possibly pre-breeding vx in endemic areas
What are some control strategies for lepto?
limit additions to herd
fence cattle from standing water
Wild animal control
What disease is Bangs?
How is Brucella contracted?
Direct contact with genital secretions from abortions (also blood, placenta, fetus)
Consumption of raw milk
Which strain is pathogenic for humans?
strain 19 vaccine is no longer used
What do you need to remember about this disease?
It is REPORTABLE
What is the government doing about this disease?
There is an eradication program since 1954.
What is the status of eradication in the U.S.?
It is nearly eradicated from cattle herds but is still in bison and elk in the Yellowstone area
What does the eradication program consist of?
quarantine infected herds
vx of young breeding females (4-12mos)
test & slaughter
surveillance at slaughter/markets
When is a state considered Brucella free?
no cattle or bison infected for 12 consecutive months
49 states are Brucella free. Which one is the hold-out?
What is the transmission in cows?
persists in mammary glands and is passed to calf through milk consumption.
infected genital secretions after abortion (most important)
What is the transmission in bulls?
infected semen passed to cow
Should you vaccinate bulls?
NO. It can result in orchitis, epididymitis, or seminal vesiculitis
As a vet, what do you do if you vaccinate a bull?
Buy the bull and give it lots of tetracycline
Who may vaccinate?
only licensed veterinarians
When can you vaccinate an adult?
only by order of the State Vet
Can you vx a preganant animal?
no, although they shouldn't be pregnant by 12 months.
What kind of organism is Neospora caninum?
What are the clinical signs of Neospora?
Abortion (mid gestation: 5-6mos) (autolyzed/mummified fetus)
no signs but chronically infected
No clinical signs and NOT infected even though dam was.
What happens in an endemic heard?
sporadic abortions due to vertical transmission
Abortions in family lines
What happens in epidemic abortions?
Which cows are most likely to abort?
How is the epidemic disease transmitted?
infective oocysts in feed or water from canine host
With vertical transmission, when is abortion more likely to occur?
during first pregnancy following infection
What is the major route of transmission in a herd?
80-100% of infected dams will have infected offspring
How can it be vertical transmission if it causes abortion?
It doesn't usually result in abortion, therefore it is maintained as a chronic infection in the herd.
Is the vertical route contagious?
What are the two asexual stages of development in intermediate hosts?
tachyzoites: actively penetrate cells and divide rapidly. Can cross placenta
Bradyzoites: slowly dividing, dominant stage
encysted within tissue cysts. Only in neural tissue. Infected for life
What happen in vertical transmission?
Bradyzoites switch to tachyzoites and then enter bloodstream. They then cross the placenta and infect the fetus. Timing of this may determine whether fetus is alive or aborted.
With horizontal transmission, what is the definitive host?
many species can be the intermediate hosts
How does horizontal transmission work?
Tachyzoites and cysts found intracellularly in IM hosts
Dogs consume infected tissue and become infected as definitive host
Dogs shed oocysts
Cows consume oocysts from dog feces-contaminated feed/water
How is N. caninum diagnosed?
necropsy IHC of fetal tissue (brain, liver, heart)
Presence does not confirm this as cause of abortion.
Negative test is info, positive only indicates infection, not causation
Where is the highest seroprevalence?
Is there a vaccine available?
Not any more
What does prevention and control entail?
exposure to tachyzoites 6wks prior to mating (provide protection against vertical trans if exposed mid-gestation.
Previous exposur are less likely to abort or give early birth
What will a test and cull strategy do?
reduce herd prevalence but leave it more susceptible to severe abortion