Pregnancy Loss Case Flashcards
Name differential diagnoses for cattle abortion (27)
- Congenital disorders
- Stress in last trimester of pregnancy
- Inseminations of pregnant cows
- PGF2α injections in pregnant cows
- Iodine deficiency: full term still born calves
- Uterine abnormalities
- Concurrent disease
- Spot a fever – likely of aborting – quite high
- Heat stress
- Insufficient luteal function
- High yielding dairy – struggle to put energy into repro and also adequate luteal function and milk production
- Bacillus
- Coxiella bumetii
- Neospora
- Fungi
- Schmallenberg
- IBR
- BVD
- Venereal disease due to campylobacter
- Dystocia
- E. Coli
- Brucella
- Trueperlla pyogenes
- Campylobacter
- Chlamydophilia abortus
- Leptospira
- Listeria
- S. Dublin
- S. Typhimurium
What questions would you ask this farmer?
Dairy farm
Lots of abortions – they are now fed up and want to do something about it
How long has it been going on?
How long into pregnancy do they abort?
Any patterns?
Open vs closed herd?
What percent of in calf cows?
Reoccurring in cows?
Record keeping?
Vaccinating and what?
Any animals on farm?
Can I visit farm and look at tidiness?
What are the signs of Neospora Caninum? (7)
- Risk of abortion in seropositive cows 2-7 x higher than in seronegative cows
- Also likely to abort year after year
- Risk of recurrent abortion: 5x
- No other clinical signs of disease in adult cattle
- Clinical disease in dogs (paralysis of the limbs)
- Weak born calves
- MOST OF THE TIME: Infected calves with no clinical abnormalities
What is the cost to the industry of Neospora caninum?
increased culling, abortions, decreased milk production, reduced value breeding stock, vet treatment, reduction in growth rate. UK: annual median cost to the average farm of €1380(range €530 to €1600
What is the life cycle of Neospora caninum?
Knowledge od Dx is needed for control
Eat poo that is infected with oocyst (dog or fox)
Cow infected
Most of the time calf is born – PI (looks healthy and behaves healthy); but if you breed she will pass on
Can also abort
Or born uninfected
Vertical transmission is variably (likely) – some farms only 30% transmit and others they all do! Immunity related.
Horizontal transmission – eat aborted calf or eating placenta of affected calf
Sylvatic transmission – if you are a IH (see next slide) and you are infected as you have eaten infected material. If the dog eats it – will be infected and go on to produce oocyst.
What are the intermediate hosts of Neospora caninum?
•Ferrets, red foxes, polecats, mink, badgers
House mice, brown rats, field mice
Wild rabbits
Rock squirrel
Common shrews, wood mice, harvest mice, white-toothed shrews, common voles
Domestic chicken, sparrows, magpies, common buzzard
Roe deer
How can we diagnose Neospora caninum? (3)
- Serology: ELISA/IFAT – make sure you find right animal before killing
- Positive sample confirms exposure, not sufficient as cause of abortion
- Compare aborting/non-aborting
- Precolostral blood sample – not always confirming
- Confirm vertical transmission has taken part. Suckle colostrum will get maternal Abs. Sample after six months of age (false negatives possible) or when pregnant (5-7mo) (Davison et al., 1999)
- May end up with false negative – goes into the animal and hides and then the IR isn’t great as in tachyzoite or bradyzoite who knows phase and hides
- False negative foetal serology
- (Bulk) milk ELISA
- Histopathology (heart and brain), non-suppurative inflammation
What do we always ask a farmer in an abortion case?
HAVE YOU SEN FETUS AND PLACETNTA (and bloods) OFF TO APHA?????????? – not always a guarantee as if the fetus is negayive it may just mean the AB response was not great enough
How can we control Neospora?(3)
- Theoretical control options
- Toltrazuril
- Vaccine
- Anecdotal evidence of decrease in abortions
- Vaccination complicates finding naturally infected animals
- Vertical transmission!
- Oocyst survival
- High temperatures (100˚C for 1 min) and 10% sodium hypochlorite for 1 hr were effectively inactivating oocysts (Neto et al., 2011)
- Limited knowledge! Silage/Pasture/TMR? – unknown how long oocyst last (thought not to be as tough as toxoplasma)
How can we prevent Neospora vertical transmission? (6)
- Low prevalence: culling of all seropositive animals
- High prevalence: breed to beef breeds, don’t keep offspring
- Only seronegative females should be introduced
- ET, harvest empryo from seropositive dam, implant in seronegative recipients (Baillergon et al., 2001) (if your animals are worth a lot of money)
- Neosporosis is not believed to be transmitted venereally so there is no need to avoid the use of N.caninum-positive bulls
- Avoid any condition that may lower the immunity of the pregnant animals; for example, vaccinate for other diseases such as BVD and leptospirosis.
How can we prevent Neospora horizontal transmission? (8)
- Prevent access of dogs, especially pups, to silage pits, hay sheds, feeding areas and concentrate food stores
- Soiling of pasture by canine faeces should be avoided
- Access of birds, rodents and other wild animals to food should be prevented
- Dogs should not have access to calving areas or recently calved animals
- Dead foetuses, dead animals, uterine discharges and placentae should be disposed of so that dogs or foxes cannot get access to them
- The safest practice would be not to feed any form of raw meat to dogs as natural infection has also been reported in sheep, goats and deer
- It is advisable to calve known Neospora positive animals in isolation from negative animals, even though horizontal transmission between cattle has not been shown to occur. Calves regularly lick placentas!! So if a negative licks a tachyzoite rich placenta – risk.
- Don’t shoot the dog! Shed for a week or 2 – don’t get disease (unless immunocompromised), immunity develops.
