Farm animals 5 Flashcards
Describe the abortion profile of tritrichomoniasis in cattle (proportion, timing, recurrence)
- Sporadic abortions
- First half of gestation
- Animal gains immunity, but likely not life long so may recur
Describe the pathology and clinical signs seen with Tritrichomonas abortion in cattle
- Placenta: retained, milkd placentitis, haemorrhagic cotyledons, thickened intercotyledonary areas covered with flocculent exudates
- No specific lesions in foetus
- Dam: few clinical signs, may show mild discharge and poor pregnancy rates
- No signs in bull
Give the samples required and method for diagnosis of tritrichomoniasis in cattle
- Placenta, foetus, vaginal/uterine discharge
- Diagnosis: detection of organism in abomasal contents, placental fluids and uterine discharges
Outline the prevention of Tritrichomonas foetus in cattle
Vaccine available but only effective in cows, does not prevent infection of bulls
How is Neospora caninum transmitted in cattle?
Ingestion of oocyst contaminated feed/water (dog faeces)
Describe the abortion profile of Neospora abortion in cattle (proportion, timing, recurrence)
- High proportion in first gestation and when infection enters a naiive herd, up to 30% in first outbreak, 5-10% enzootic
- Abortion can occur at any stag but most comon 5-6 months
- Recurrence decreases with parity but always possible
Describe the pathology and clinical signs seen with Neospora abortion in cattle
- Placenta: no specific gross lesions
- In dogs and dams generally subclinical infection other than abortion
- Foetus: may be autolysed
- Microscopic pathology: focal encephalitis with necrosis and non-suppurative inflammation, hepatitis in foetus
Give the samples required and method for diagnosis of neosporosis in cattle
- Placenta,foetus (brain, heart, liver, body fluids), serum samples from dam
- Diagnosis: detection of antigen in brain histology samples, immunohistochemistry on tissue samples, detection of Abs via PCR or ELISA
Outline the treatment and prevention of neosporosis abortion in cattle
- Treat clinically affected dogs with clindamycin or TMPS, prevent access for feedstuffs
- Do not keep heifer calves born to seropositive cows (may be PI)
How is BVDV transmitted?
Vertical transmission and horizontal
Outline the abortion profile of BVDV (proportion, timing, recurrence)
- Usually low proportion
- Abortion up to 4 months gestation
- Uncommon recurrence - immunity develops
Describe the pathology seen with abortion resulting from BVDV
- Placenta often retained, no specific lesions
- Foetus no specific lesions, autolysed, mummified
- Dam likely no signs, may be PI, sometimes may be small, stunted, oddly haired, poor condition
Give the samples required and method for diagnosis of BVDV as a cause of abortion
- Placenta, foetus (preferably spleen), dam and herdmate serum
- Diagnosis: viral isolation, immunologic staining, PCR, detection of precolostral antibodies in aborted calves
Outline the control of BVDV
- Vaccine before breeding
- Cull PIs
- Screen new animals
- Closed herd
- Buy in from free
Outline the transmission of BHV-1 causing abortion in cattle
- Carriers
- Via WBC to placenta
Outline the abortion profile of BHV-1 (proportion, timing, recurrence)
- 5-60% in non-vaccinated herds
- Abortion at any stage but most common from 4 months to term
- Immunity develops so recurrence uncommon
Describe the pathologic lesions seen with abortion due to BHV1
- In majority of cases no gross lesions
- Placenta: necrotising vasculitis
- Foetus: autolysed, foci of necrosis in the liver
Give the samples and methods required for the diagnosis of BHV1 as a cause of abortion
- Placenta, foetus, serum samples from dam
- Diagnosis: immunohistochemistry in samples from kidney and adrenal glands, blood serology PCR
Outline the control of BHV1
- Vaccination (intranasal)
- Can be used in pregnant cattle
- For eradication use serological surveillance, cull reactors and careful biosecurity
How is bluetongue virus transmitted?
Culicoides midges or semen from viraemic bulls
Describe the abortion profile that results from bluetongue virus (proportion, timing, recurrence)
- Usually low proportion of herd affected
- Variable timing
- Unlikely to recur
Describe the pathology seen with abortion resulting from bluetongue
- Non-specific, foetus autolysed
- Dam shows transient fever followed by hyperaemia, erosions of buccal and lingual mucosa, hypersalivation
Give the samples and methods required for diagnosis of bluetongue as a cause of abortion
- Placenta, foetus, serum samples from the dam
- Diagnosis by virus isolation
Outline the control of bluetongue virus
- Control of midges
- Vaccination of susceptible animals using one serotypes, then another 1 month later