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B.V.D.Bovine Viral Diarrhoea Virus
BVDHighly contagious viral infection
Most infections have no clinical signs
Sero-conversion, virus elimination and life-long immunity
BVDReproductive effects
Infection during pregnancyEffect on foetusMonth 1 Embryo deathMonth 2-4 Persistent Infection (PI)Month 5-9 abortions, deformities, etc
BVDReduced immune function
Immuno-suppressionEnteric/GutRespiratoryReproductiveMastitis
Mucosal Diseaselow morbidity / high mortality
BVDSignificance of PI
Most important source of infection in herdMay not be present when you search for itFrequently unthriftyMay succumb to mucosal diseaseMay live for a long time in herd Always antibody negative
BVDEconomics of infection
Initial outbreak€19 - €600 per cow
Herd level€31 -€100 / cow / year
National level€15 - €20 / cow / year
BVDDiagnosis of individual
Antibody Sero-positive for lifeVirus Blood
Ear punchmay need to be
confirmed 3 weeks later
BVDHerd level screening
Adult herd Dairy Bulk milk whole herd for Ab and
Virus Beef Bleed 15 non-vaccinated from
each group for Ab and Virus(pooled?)Young stock
Bleed 5-10 home bred non-vaccinated 8-24 month old from each separate group for Ab and Virus
BVDHerd level diagnosis
Whole herd virus check 2 year project
Calf ear punch National scheme may be launched in near future
Bulk Tank Milk:- Antibody Non-vaccinated herd see
appearance of AbVaccinated herd -monitor levels for
spikesVirus Shows presence of circulating virus
in milking herd
BVDRisk factors for introduction
Purchase PI animal, Dam with PI,Animal contact Boundaries, Shows etcVisitorsEquipmentEmbryos
BVD
Ideal worldClosed herdNo purchase of pregnant animalsQuarantine / testing of newAvoid fence contactLimit access on farm disinfection, clothing
I.B.R.Infectious Bovine Rhinotracheitis
IBR
Respiratory disease emerged in California in early 50’s
UK in early 60’sMainland Europe in early 70’sIreland in 1989
IBRFever 4-5 daysApathyAnorexia(Milk drop)Respiratory Red nose, plaques, cough, nasal
discharge, conjunctivitisReproduction Abortion (direct and indirect)Death
IBREstablishes life-long latency in nerve tissue
Reactivation following stresses such as:-transport, calving, weather, over-crowding, corticosteroids.
IBREconomics of infection
Reduction in milk production in antibody positive cows
c. 0.92kg / day in one study150kg / year (2%) in another
Loss of genetics value
IBRDiagnosis of individual
Virus isolation Deep intra-nasal swabs in clinically non-affected animals
AntibodySerum, milkAntibody does not eliminate virus, infected for life
Can do paired blood antibody 3 weeks apart to demonstrate rising levels to indicate disease
IBRHerd level screening
Bleed 5-8 animals for antibody from each separate group
Bulk milk antibodymonitor for arrival or changes in Ab level
IBRControl
Do nothingVaccinate in face of outbreakVaccinate to control clinical signsEradicate
IBRBio-security
Risk factorsPurchaseAnimal contact Boundaries, Shows etcVisitorsEquipment
IBRIdeal world
Closed herdNo purchase of animalsQuarantine / testing of newAvoid fence contactLimit access on farm disinfection, clothing
IBRVaccintion
LiveInactivated
Evidence divided on protocols
JohnesMycobacterium Avium Paratuberculosis
MAP
MAP
Chronic granulomatous enteritis of ruminants
Diarrhoea, weight loss, reduced milk yield, death
MAP ingested from environment, colostrum or milk
MAPEconomics of infection
Reduced milk production (600 – 2,200kg/lact)Reduced constituents (fat, protein)Increased mortalityWeight lossPremature cullingReduced slaughter valueConsumer worries
MAPDiagnosis of individual
CultureFaeces, milk, bulk tank, semen, dust
PCRSemi-quantitative,
AntibodyAccuracy of ELISA (Se and Sp concerns) False positives post TB testing
MAPHerd level screening
CultureEnvironmental dust, Bulk tank milk
BTMAntibody Se concerns (0.07 – 0.94)PCR lower level in milk
No test suitable to demonstrate freedom from infection.
MAPRisk factors
IntroductionPurchase, manure/slurry, water
TransmissionCalving pen hygiene, udder cleanliness, colostrum from positive cows, exposure to faeces, mixed age housing
MAPControl
Danish system traffic light systemLow risk Green last 4 tests neg.High risk Red 2 or 3 pos from last 4
cull at end of seasonYellow separate calving pen
remove calf immediatelycolostrum from green cows
onlygroup by agemilk replacer and separate
housing
What can we do for you?
Interpret diagnostic testsPlan herd diagnostic assessment
Bio-security adviceVaccination planning