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