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Therio - Bovine - EED & Abortion in Cattle 1

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drraythe's version from 2017-09-10 02:12

Intro

Question Answer
What is EED/early embryonic death defined as?Deaths occurring from the day of conception until D42 of gestation (end of differentiation). Often go unnoticed bc embryo resorbed/aborted
A major cz of "rebreeder" cows isEED (early embryonic death)
Until WHEN is it an EED?Until D42
During what times is it considered an abortion?From D42 up to D260
During what timetable would it be considered a stillbirth?From D260 to term
EED → abortion → stillbirth0-42 → 42-260 → 260-term
3 general ways abortion can happen?(1) Various agents infect the fetus itself which may result in abortion or mummification/fetal malformation eg most viruses & some bact
(2) Various agents cz a Placentitis which may cz abortion eg. Most bacteria
(3) Anything that affects cow’s wellbeing (stress, temp, etc) cz Release of inflammatory mediators incld. PGF… knocks out the CL & cow will abort.
Examples of 3 non-infectious agents that can cz abortion?Poisonous plants
Nitrates
Pharmaceuticals eg. PGF!
Examples of Poisonous plants that can cz abortion?Poison Hemlock
Locoweeds
Pine needles
Broomweed
Fescue
If you are called to a farm where a farmer is having trouble w/ abortions, what precaution should you be mindful of?MANY AGENTS THAT CZ ABORTION ARE ZOONOTIC!!
When examining the abortus, what should you look for w/ the placenta?Are only cotyledons affected? Are Intercotyledonary areas affected? (Brucella)
Which dz czs lesions in the intercotyledonary areas?BRUCELLA
When you are examining the abortus, & looking for the fetus, what should you be looking for?Condition of the fetus (fresh, decomposed, mummified?), Meconium staining, Hair covering? Around muzzle & up to hooves?
Why, when looking at an aborted fetus, would you try to see if there was hair covering on the muzzle & up to the hooves?If fur covered, full term abortion
If not, before term
What are the 4 main samples you want to attain for Dx of abortion?(1) Blood for serology (collect another sample 2-3 weeks) (if fir whole herd, 10% of herd)
(2) Urine for culture & cytology
(3) Vaginal swabs
(4) Milk [samples can be for individual OR herd]
What samples would you want to collect from the abortus for dx?ENTIRE PLACENTA if possible, amniotic fluid, ENTIRE FETUS if possible
If you cannot send in the entire abortus (fetus+placenta) for testing, what parts are ESSENTIAL for you to send in?Liver
Adrenals
Kidney
Lung
Placenta
Abomasal content
How do you fix the abortus samples for dx?1) Fresh chilled
2) Fixed in 10% formalin
memorize

BACTERIAL CZS OF ABORTION

Question Answer
What kind of agent is Brucella abortus?Gram neg cocco-bacillus
What are the names of the dzs which Brucella abortus czs?“Contagious abortion” (CA); “Bang’s Dz”; “Enzootic abortion”
Is Brucella zoonotic?YES!!! Czs acute febrile illness w/ non-specific signs, May cz neurological symptoms, & May get chronic illness that waxes & wanes (Arthritis, chronic fatigue, epididymo-Orchitis)
Is Brucella in the US?Only in Greater Yellowstone area in free-ranging bison & elk
How is Brucella acquired?Penetrates mucosa of oral/nasal cavity after ingestion Source: aborted fetus/membranes lochia
Explain the pathogenesis of BrucellaPenetrates oral/nasal mucosa → Replicates in lnn, Czs bacteremia → shed in milk & in products of abortion (major source on Infxn)
Why does Brucella make its way to the preg uterus?Special affinity for erythritol from gravid uterus (present from 5th mo of gestation)
What are the clinical sings of Brucella in COWS?Late term abortion storms
Does Brucella cz repeat abortions?80% of cows will not abort again
What are the CSs of Brucella in BULLS?Orchitis, epididymitis & Infxn of accessory sex glands
What is a CS that both cows & bulls get from Brucella?Uni- or bilateral hygromas (false bursa, which is a nonpainful, fluid-filled swelling surrounded by a thick, fibrous capsule that develops under the skin. )
Pathology of Brucella → what is the MOST consistent lesion? (In terms of cows aborting)Placentitis
WHERE & HOW does Brucella affect the placenta?Placentitis (MOST CONSTANT LESIONS) which occurs in the intercotyledonary area. It will look Dry, thickened & cracked (like Moroccan leather). Also, Cotyledons may be covered w/ exudate & have foci of necrosis
How do you Dx Brucella?(1) Isolation of the organism via culture OR immunohistochemistry
(2) Serological testing (antibodies to the organism) [Rose Bengal test for screening, ELISA for pos samples, Milk ring test (bulk milk samples)
What is the screening test for Brucella?Rose Bengal
How do you Tx Brucella?Since it is a Notifiable Dz (State-Federal Brucellosis Cooperative Eradication Program) there is a Quarantine & slaughter-out policy
How can you prevent Brucella?VX
What are the 2 Brucella Vx, & how do they differ?(1) STRAIN 19 is for heifers only
(2) RB51 for heifers & cows
Which Vx for Brucella won’t interfere w/ serological testing?RB51 strain
Explain the difference btwn intended/maintenance hosts (who?) w/ Leptospira interrogans versus accidental hosts (which lepto is usually the prob w/ accidental hosts?)(1) INTENDED (rodents): More chroniCSubclinical Dz, Xmission usually direct contact w/ infected urine/placental fluids/milk/transplacental/venereal. Czs persistence of Infxn, & is difficult to Dx
(2) ACCIDENTAL hosts: czs an acute Infxn w/ a Short renal phase. Xmission usually indirect eg. Water sources, urine-contaminated environment (L. pomona most commonly implicated in non-host adapted species)
How does Xmission of leptospirosis usually occur?Xmission usually indirect eg. Water sources, urine-contaminated environment
Is leptospirosis zoonotic?YES
What kinda agent is leptospirosis?Small, aerobic spirochaetes
Pathogenesis of lepto?Xmission through mm. of eye, nose, vagina, penis & water softened skin (OR venereal xmission) → Bacteremia – localizes in kidneys & genital tract of male & female → Shed in urine & semen
What are the CSs of a lepto Infxn?Infxn in non-pregnant cattle usually subclinical. Infertility!! Abortions from 4 mos of gestation to term (Abortion rates usually lower w/ Hardjo (3-30%) but may be very high w/ Pomona (>50%))
How might the aborted fetus look if it was done in by lepto?May look icteric, & have Tubular necrosis in kidney
What are 2 diagnostic methods for lepto?(1) Isolation of the organism
(2) Demonstration of antibodies
Where is the best place to isolate the lepto organism? (Tests to isolate?)Kidney & use Fluorescent antibody or IHC stains
How can you Tx lepto?ABx to try & decrease shedding (host-adapted strains) eg. Tetracyclines
How are some ways you can prevent/control lepto?Annual Vx against incidental strains, Reduce contact to infected water courses, control rodents
Is Salmonellosis zoonotic from cows to ppl?YES
Which strains of salmonella are most commonly associated w/ abortion?Salmonella dublin & S. typhimurium most commonly isolated
How do cows contract Salmonellosis?Consuming feedstuffs or grazing on pasture that has been contaminated w/ feces from infected animals/slurry/animal waste/human waste etc
What is the pathogenesis of Salmonellosis? (Leading to abortion)consume food contaminated w/ feces- → bacteriemia where organism spreads to liver, spleen, lungs & lnn → localizes in the placentomes causing a Placentitis & fetal death
*What are the main CSs of Salmonellosis?Often marked pyrexia (>104°F) + Severe diarrhea ( ← -UNIQUE. KNOW.), & Abortion (may get abortion storms) (sometimes no CS)
What is the main pathology/system/area affected by Salmonellosis?Mainly Placentitis
What are 2 ways to Dx Salmonellosis?(1) Isolation of organism (culture)
(2) Demonstration of antibodies (usually S. dublin)
How can you treat/control Salmonellosis?Isolate aborting cattle, Dispose of infective material (incinerate), Clean & disinfect premises, Vx, biosecurity, closed herd
What czs Listeriosis?Listeria monocytogenes
Where does listeria like to live in the environment?Common soil inhabitant
How do most cows get Listeriosis?Outbreaks of Listeriosis linked to feeding spoiled silage
Is Listeriosis zoonotic?YES-- contaminated food
What are the CSs of Listeriosis in cows?Weight loss
Fever
Endometritis
RFM
ABORTION
If an abortion was czd by Listeriosis, how might the abortus look like?(PLACENTA) Pin point yellowish necrotic foci on tips of cotyledons + diffuse intercotyledonary Placentitis (FETUS) might be autolyzed if retained in the uterus for a few days, Necrotic foci in liver/spleen
How do you control listeria abortion outbreaks?Do not feed spoiled silage!!
memorize

VIRAL CZS OF ABORTION + PROTOZOAL CZS OF ABORTION

Question Answer
Bovine Herpesvirus-1 (BHV-1) presents in what 2 ways?(1) URT Infxn = Infectious Bovine Rhinotracheitis virus (IBR)
(2) Genital Infxn = Pustular Vulvovaginitis in females & Balanoposthitis in males
What should you know about the nature of Herpes virus?It is forever - so can cz latent Infxns, & then Get recrudescence during times of stress
How is Bovine Herpes virus spread?Previously recovered animals may serve as a source of Infxn, w/ the virus shed in respiratory & genital secretions. Xmitted by direct contact w/ URT, conjunctiva or genital tract
**What is the main way that cows would get a BHV-1 Infxn, which would cz abortion?RESPIRATORY Xmission
What are the CSs of BHV-1 URT Infxn?Respiratory Dz/Conjunctivitis in non-immune pregnant females = viremia = fetal Infxn = abortion! CAN cz abortion storms (Usually btwn. 4-8 mos of gestation)
What should you know about the Vx for BHV-1?Abortion may occur if pregnant females are vaccinated w/ modified-live vaccine- for them, use the inactivated
Which form of BHV-1 czs the most abortions?THE RESP 1, actually. Bc they can get a viremia which infects the fetus.
What are the CSs of the genital Infxn of BHV-1?Pustular Vulvovaginitis, Balanoposthitis, Usually not associated w/ abortion
CQ: Hydroamnion is bc..Fetus cant swallow is underlying cz. (Slow onset, not severe distension, not adventitious placentation)
CQ: Prostaglandin induces estrus in cows only when given duringDiestrus
CQ: Most common cz of poor repro performance in cows on lg dairy farm is..Poor estrus detection
CQ: Rectal palp cow, find mummy fetus. What do?Inject PGF IM (bc CL is maintaining) (uterus is responsive to Oxytocin only w/ estrogen too → so useful post-partum)
CQ: Most dependable indicator of preg in cow 75d after AI?Palpation of the fetus. (Asymmetry of horns is not definitive, fremitus is not definitive to preg, fluctuations in the horn not definitive, amniotic vesicle is too soft at 75-- up to 60)
CQ: Prolapse of the uterus is frequently association w/Hypocalcemia (not moving, doesn’t retract self)
How does the abortus appear when the cz was BHV-1?Delayed expulsion of fetus after death w/ resultant autolysis, tiny necrotic foci in liver & lungs
Explain how BVDV affects non-preg cowsAcute Infxns in seroneg
Immunocompetent cattle
Usually unapparent
Might have Pyrexia, nasal discharge, & might result in immunosuppression
Explain how BVDV affects PREGNANT CATTLE (Transplacental Infxns)These Occur in susceptible pregnant cattle depends on the stage of gestation
(a) <100 days preg, leads to fetal death & abortion
(b) If mid to late gestation, >150days, the calf’s immune system competent, therefore virus neg, antibody pos calf (+/- abortions)
(c) If 100-150 days, abortions or congenital defects eg. Microencephaly, cerebellar hypoplasia, hydrocephalus, etc., & there can be Birth of persistently infected calf (PI), which is Virus pos, antibody neg calf (source of Infxn-- if re-infected, gets mucosal dz & dies)
CSs/progression of a calf w/ a persistent Infxn of BVDV?Happens w/ Birth of calves infected during 100-150d of gestation. May be weak at birth, stunted w/ poor growth rates & die at a young age. They shed large amts of virus. Then, When PI is subsequently infected by cytopathic strain of virus, they develop MUCOSAL DZ which has CS of Anorexia, pyrexia, ulcerative lesions on muzzle & tongue & in GIT; death
If you want to perform an IHC test on calves for BVDV, what sample can you use?Performed on skin biopsy samples (ear notches when calves tagged)
If you want to perform a virus isolation on calves for BVDV, what sample can you use?Blood
What are some ways to prevent/control BVDV?Testing herd to identify PI’s & eliminate, Keep a closed herd (test new introductions), Vx
Who is the definitive host of neospora caninum? Intermediate host?Definitive: DOGS
Intermediate host: COWS
What is the lifecycle of Neospora caninum like?Dog sheds eggs in feces
Cow ingests eggs on ground (horizontal Xmission)
The neospora is vertically Xmitted from mother cow to offpsring, abortion is possible.
Dog becomes reinfected if eats abortus/placenta/cow carcass
*How can you Dx neospora caninum?Virtually diagnostic microscopic lesions, Nonsuppurative encephalitis, myositis, hepatitis & myocarditis
How can you try to control/prevent neospora caninum?(1) Interrupt predator-prey life cycle (Dispose of carcasses & placentas appropriately, Feed & water stored appropriately to prevent fecal contamination)
(2) Identify chronically infected cows & eliminate from the herd
How is BHV-1 spread to cz the venereal dz?NB! Venereal Xmission by contaminated semen
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