Therio- Bovine- EED & Abortion in Cattle 1

wilsbach's version from 2015-11-04 18:43


Question Answer
what is EED/early embryonic death defined as?deaths occuring from the day of conception until D42 of gestation (end of differentiation). Often go unnoticed bc embryo resorbed/aborted
a major cause of "rebreeder" cows isEED (early embryonic death)
Until WHEN is it a EED?until D42
during what times is it considered an abortion?From D42 upto 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 and some bact (2) Various agents cause a placentitis which may cause abortion eg. Most bacteria (3) Anything that affects cow’s wellbeing (stress, temp, etc) cause Release of inflammatory mediators incl. PGF… knocks out the CL and cow will abort.
examples of 3 non-infectious agents which can cause abortion?poisonous plants, nitrates, Pharmaceuticals eg. PGF!
examples of Poisonous plants which can cause abortion?Poison Hemlock, Locoweeds, Pine needles, Broomweed, Fescue
if you are called to a farm where a farmer is having trouble with abortions, what precaution should you be mindful of?MANY AGENTS WHICH CAUSE ABORTION ARE ZOONOTIC!!
when examining the abortus, what should you look for with the placenta?are Only cotyledons affected? are Intercotyledonary areas affected? (Brucella)
which dz causes lesions in the intercotyledonary areas?BRUCELLA
when you are examining the abortus, and looking for the fetus, what should you be looking for?Condition of the fetus (fresh, decomposed, mummified?), Meconium staining, Hair covering? Around muzzle & upto hooves?
why, when looking at an aborted fetus, would you try to see if there was hair covering on the muzzle and up to the hooves?if fur covered, full term abortion. if not, before term
what are the 4 main samples youd 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


Question Answer
what kind of agent is Brucella abortus?Gram negative cocco-bacillus
what are the names of the dzs which brucella abortus causes?“Contagious abortion” (CA); “Bang’s disease”; “Enzootic abortion”
is brucella zoonotic?YES!!! Causes acute febrile illness with non-specific signs, May cause neurological symptoms, and May get chronic illness that waxes & wanes (Arthritis, chronic fatigue, epididyorchitis)
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, Causes bacteremia--> shed in milk and in products of abortion (major source on infection)
why does brucella make its way to the preg uterus? Special affinity for erythritol from gravid uterus (present from 5th month of gestation)
what are the clinical sings of brucella in COWS?late term abortion storms
does brucella cause repeat abortions?80% of cows will not abort again
what are the clinical signs of brucella in BULLS?Orchitis, epididymitis & infection of accessory sex glands
what is a CS that both cows AND 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 consistant lesion? (in terms of cows aborting)placentitis
WHERE and 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 with 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 positive 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 disease (State-Federal Brucellosis Cooperative Eradication Program) there is a Quarantine & slaughter-out policy
how can you prevent brucella?VX
what are the two brucella vx, and how do they differ?(1) STRAIN 19 is for heifers only (2) RB51 for heifers and cows
which vx for burcella wont interfere with serological testing?RB51 strain
explain the difference between intended/maintainance hosts (who?) with Leptospira interrogans versus accidental hosts (which lepto is usually the prob with accidental hosts?)(1) INTENDED (rodents): More chronic/subclinical disease, Transmission usually direct contact with infected urine/placental fluids/milk/transplacental/venereal. Causes persistance of infection, and is difficult to dx (2) ACCIDENTAL hosts: causes an Acute infection with a Short renal phase. Transmission usually indirect eg. Water sources, urine-contaminated environment (L. pomona most commonly implicated in non-host adapted species)
how does transmission of leptospirosis usually occur?Transmission usually indirect eg. Water sources, urine-contaminated environment
is leptospirosis zoonotic?YES
what kinda agent is leptospirosis?Small, aerobic spirochaetes
pathogenesis of lepto?Transmission through m.m. of eye, nose, vagina, penis & water softened skin (OR venereal xmission)--> Bacteraemia – localizes in kidneys & genital tract of male & female--> Shed in urine & semen
what are the clinical signs of a lepto infection?Infection in non-pregnant cattle usually subclinical. Infertility!! Abortions from 4 months of gestation to term (Abortion rates usually lower with Hardjo (3-30%) but may be very high with Pomona (>50%))
how might the aborted fetus look if it was done in by lepto?may look icteric, and have Tubular necrosis in kidney
what are two 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 and use Fluorescent antibody or IHC stains
how can you tx lepto?Antibiotics to try & decrease shedding (host-adapted strains) eg. Tetracyclines
how are some ways you can prevent/control lepto?Annual vaccination 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 with abortion?Salmonella dublin & S. typhimurium most commonly isolated
how do cows contract salmonellosis?Consuming feedstuffs or grazing on pasture that has been contaminated with feces from infected animals/slurry/animal waste/human waste etc
what is the pathogenesis of salmonellosis? (leading to abortion)comsume food contaminated with feces---> bacteraemia where organism spreads to liver, spleen, lungs & lnn--> localizes in the placentomes causing a placentitis & fetal death
*what are the main clinical signs of salmonellosis?Often marked pyrexia (>104°F) + Severe diarrhea (<---UNIQUE. KNOW.), and Abortion (may get abortion storms) (sometimes no CS)
what is the main pathology/system/area affected by salmonellosis?Mainly placentitis
what are two 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 causes 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 clinical signs of listeriosis in cows?Weight loss, fever, endometritis, RFM, ABORTION
if an abortion was caused by listeriosus, how might the abortus look like?(PLACENTA) Pin point yellowish necrotic foci on tips of cotylendons + diffuse intercotyledonary placentitis (FETUS) might be autolysed 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!!


Question Answer
Bovine Herpesvirus-1 (BHV-1) presents in what two ways?(1) URT infection= infectious bovine rhinotracheitis virus (IBR) (2) Genital infection = pustular vulvovaginitis in females & balanoposthitis in males
what should you know about the nature of herpes virus?it is forever-- so Can cause latent infections, and then Get recrudescence during times of stress
how is bovineherpes virus spread?Previously recovered animals may serve as a source of infection, with the virus Shed in respiratory & genital secretions. Transmitted by direct contact with URT, conjunctiva or genital tract
**what is the main way that cows would get a BHV-1 infection which would cause abortion?RESPIRATORY transmission
what are the clinical signs of BHV-1 URT infection?Respiratory disease/Conjunctivitis in non-immune pregnant females= viraemia= fetal infection= abortion! CAN cause abortion storms (Usually betw. 4-8 months of gestation)
what should you know about the vx for BHV-1?abortion may occur if pregnant females are vaccinated with modified-live vaccine- for them, use the inactivated
which form of BHV-1 causes the most abortions?THE RESP ONE, actually. because they can get a viremia which infects the fetus.
what are the clinical signs of the genital infection of BHV-1?Pustular vulvovaginitis, Balanoposthitis, Usually not associated with abortion
CQ: hydroamnion is bc..fetus cant swallow is underlying cause. (slow onset, not severe distension, not avdentitious placentation)
CQ: prostaglandin induces estrus in cows only when given duringdiestrus
CQ: most common cause 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 with 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 withhypocalcemia (not moving, doesnt retract self)
how does the abortus appear when the cause was BHV-1?Delayed expulsion of fetus after death with resultant autolysis, Tiny necrotic foci in liver & lungs
explain how BVDV affects non-preg cowsAcute infections in seronegative, immunocompetent cattle. Usually inapparent, might have Pyrexia, nasal discharge, and might result in immunosuppression
explain how BVDV affects PREGNANT CATTLE (Transplacental infections)These Occur in susceptible pregnant cattledepends on the stage of gestation (a) <100 days preg, leads to fetal death & abortion (b) if mid to late gestation, >150days, the calfs immune system competent, therefore virus negative, antibody positive calf (+/- abortions) (c) if 100-150 days, abortions or congenital defects eg. Microencephaly, cerebellar hypoplasia, hydrocephalus, etc., and there can be Birth of persistently infected calf (PI), which is Virus positive, antibody negative calf (source of infection-- if reinfected, gets mucosal dz and dies)
clinical signs/progression of a calf with a persistant infection of BVDV?happens with Birth of calves infected during 100-150d of gestation. May be weak at birth, stunted with poor growth rates & die at a young age. They Shed large amounts 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 and in GIT; death
If you want to perform a 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), Vaccination
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 transmission). The neospora is vertically transmitted 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 and 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 cause the venereal dz?NB! Venereal transmission by contaminated semen