Download Jenna Donaldson

An Outbreak of Viral
Respiratory Disease in an
Ontario Dairy Herd
Jenna Donaldson
OVC 2013
http://www.sciencedaily.com/releases/2010/06/100607065902.htm
Case History
 Signalment

Holstein herd milking 53 cows
 Presenting

Complaint
Whole herd off feed
Herd Management
Barn design
 Nutrition



Vaccine protocol


Total mixed ration
MLV
Biosecurity

No showing
animals, heifers
raised on farm
Schematic of Barn Layout
Background

Above-average maximum daily temperature and
relative humidity prior to initial farm visit
June 2012
Initial farm visit
http://kitchenerwaterloo.weatherstats.ca/charts/relative_humidity-1year.html
http://climate.weatheroffice.gc.ca/climateData/generate_chart_e.html?timeframe=2&Pr
ov=ONT&StationID=48569&dlyRange=2010-04-18|2012-1113&Year=2012&Month=6&type=line&MeasTypeID=maxtemp&Day=13
Initial Investigation

Water


No changes
Feed



New 1st cut haylage fed
for 4 days
Gradual decrease in feed
intake over 3 days
Mold contamination of
high-moisture corn
http://www.kosvi.com/courses/vpat5215_1/vpat5310/
Herd Exam
Milking cows slightly dull
 Mild tachypnea w/ normal respiratory effort
 Increased mucoid nasal discharge
 40% of herd scouring
 Many cows pyrexic
 Rumen motility normal to decreased
 Not interested in TMR
 No mucosal lesions noted

Viral Respiratory
Disease Differentials
 Bovine
coronavirus
 Parainfluenza-3
 Infectious bovine rhinotracheitis
 Bovine respiratory syncytial virus
 Bovine viral diarrhea
Bovine Coronavirus
Pneumoenteric virus
 Fecal-oral and aerosol transmission
 Subclinical infection
 3 common clinical syndromes
 Respiratory disease typically mild

Initial Management

Vaccinated all animals with intranasal
IBR/BRSV/PI-3 modified-live vaccine
Milking Cow Management
Rectal
# of Cows Treatment Administered
Temperature (°C)
<39.5°C
19
Vaccine only
39.5-39.9°C
11
Vaccine, ketoprofen IM once
>40.0°C
23
Vaccine, ketoprofen IM once, ceftiofur IM
for 3 days
53 cows
total
Lab Diagnostics for
Respiratory Disease



Polymerase chain reaction (PCR) and/or virus
isolation
 Nasal swabs from live animals
 Fecal samples (useful for bovine coronavirus)
 Postmortem: URT tissue, lung, lymph nodes, liver
Virus neutralization (serum)
Histology on postmortem tissues
Laboratory Diagnostics





Bovine coronavirus titres
Acute and convalescent
samples (14 days apart)
Virus neutralization at
AHL
Four cows tested
No clear demonstration
of seroconversion
Bovine Coronavirus Titres
Cow #
Acute
Convalescent
1
1:512
1:512
2
1:512
1:512
3
1:512
1:1024
4
1:512
1:1024
Prevention and Management
 Nutrition
and silo management
 Ventilation and barn design
 Vaccination program
 Biosecurity
Herd Outcome
June 2012 Production
3500
Volume (L)
3000
2500
2000
1500
1000
Initial farm visit
500
0
7
9
11
13
15
17
19
21
23
25
27
Pickup Date in June 2012


Milk production returned to normal in ~14 days
One abortion at 60 days gestation
Cost to Producer

Veterinary costs: ~$1600

Professional time and products (intranasal vaccine, antiinflammatory, antimicrobials)

Estimated lost milk: ~$4100

Laboratory diagnostics


Coronavirus titres x 4 cows: $150
Full respiratory serology panel: $120 /cow
Acknowledgements



http://rocksolidnutrition.wordpress.com/category/dairy/
Dr. Ray Reynen
Heartland Veterinary
Services
Dr. Jessica Gordon