texas a&m university college of veterinary medicine disease.pdf · natural infection. foot -and...

FootFoot--andand--Mouth Disease Mouth Disease

Texas A&M University Texas A&M University

College of Veterinary MedicineCollege of Veterinary Medicine

Jeffrey MusserJeffrey Musser DVM, PhD, DABVPDVM, PhD, DABVP

Suzanne Burnham, DVMSuzanne Burnham, DVM

FootFoot--andand--Mouth DiseaseMouth Disease

FootFoot--andand--mouth Diseasemouth Disease

Disease BasicsDisease Basics



ContentsContents

Definition and EtiologyDefinition and Etiology

Host rangeHost range

Incubation Incubation

Clinical signsClinical signs

TransmissionTransmission

Diagnosis Diagnosis

Differential DiagnosisDifferential Diagnosis



Known around the world asKnown around the world as

AftaAfta epizoticaepizotica

BekBek--enen--klouseerklouseer

FiebreFiebre AftosaAftosa

FievreFievre aphteuseaphteuse

MaulMaul--undund--KlauenseucheKlauenseuche



FootFoot--andand--mouth mouth

disease is a highly disease is a highly

contagious, viral contagious, viral

disease of domestic disease of domestic

clovencloven--hoofed and hoofed and

many wild animals many wild animals

characterized by characterized by

erosions in the erosions in the

mucosa of the mouth mucosa of the mouth

and hooves.and hooves.Image courtesy of Dr Tom McKenna


This devastating disease is considered to This devastating disease is considered to

be the most important livestock disease in be the most important livestock disease in

the world.the world.

It is It is THETHE most contagious virus disease of most contagious virus disease of

animals.animals.

It has not occurred in the US since 1929.It has not occurred in the US since 1929.


Worldwide Occurrence of FMD

Worldwide Occurrence of Worldwide Occurrence of

FMDFMD

AAOOAAOO

AACCOOOO

AAAA OO

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OO

AAAA

AA

AAAA

AsAsAsAs

AsAs

AsAs

SATSAT

SATSAT

CC

CC

CCOO

OO

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SATSAT

AA


Countries that are footCountries that are foot--andand--mouth diseasemouth disease--free free do do NOTNOT want to rewant to re--import import the diseasethe disease

FMD free countries have FMD free countries have instituted embargoes on instituted embargoes on agricultural imports from agricultural imports from countries where effective countries where effective control is not practicedcontrol is not practiced


Important factorsImportant factors

Short incubation periodShort incubation period

Release of virus prior to appearance Release of virus prior to appearance

of clinical signsof clinical signs

Massive quantities of virus releasedMassive quantities of virus released


Extended survival in the environmentExtended survival in the environment

Multitude of routes of virus transmissionMultitude of routes of virus transmission

Minimal size of the infective doseMinimal size of the infective dose

Aerosol transmission possible up to 250 Aerosol transmission possible up to 250

km depending on strain and km depending on strain and

environmental conditions (10km, environmental conditions (10km,

170km, 250km reported over water)170km, 250km reported over water)



Although not very lethal to Although not very lethal to

adult animals, it causes adult animals, it causes

serious production losses.serious production losses.

FMD is a major FMD is a major constraint to international constraint to international trade in livestock and trade in livestock and livestock productslivestock products


FootFoot--andand--mouth Disease:mouth Disease:

EtiologyEtiology





Diagnosis Diagnosis



EtiologyEtiology

The virion is nonThe virion is non--enveloped, small,enveloped, small,

(about 23(about 23--25 nm in 25 nm in

Diameter), and hasDiameter), and has

icosahedral symmetry. icosahedral symmetry.

It is composed of a It is composed of a

singlesingle--stranded RNA stranded RNA

genome of about 8,000genome of about 8,000

nucleotides.nucleotides.


EtiologyEtiology

FootFoot--andand--mouth Disease virus (FMDV)mouth Disease virus (FMDV)

FamilyFamily Picornaviridae,Picornaviridae, genusgenus AphthovirusAphthovirus

7 serological types: 7 serological types:

–– Type A Type A

–– Type O, Type O,

–– Type C, Type C,

–– South African Territories (SAT) 1, South African Territories (SAT) 1,



–– and Asia 1and Asia 1


EtiologyEtiology

FootFoot--andand--mouth Disease virus (FMDV)mouth Disease virus (FMDV)

Over 60 subtypesOver 60 subtypes

Antigenic variation seems Antigenic variation seems

to be greatest for Serotype A.to be greatest for Serotype A.


FootFoot--andand--mouth Disease: mouth Disease:

EtiologyEtiology





Diagnosis Diagnosis



Host RangeHost Range

All clovenAll cloven--hoofed hoofed domestic animalsdomestic animals::

Cattle and BuffaloCattle and Buffalo

Sheep Sheep

GoatsGoats

SwineSwine



Most clovenMost cloven--footed footed wild animalswild animals::

Deer Deer

Bison Bison

Feral hogsFeral hogs

AntelopeAntelope



Water buffalo Water buffalo can be carriers forcan be carriers for

5 years5 years

Llamas and alpacasLlamas and alpacas

are susceptible, butare susceptible, but

of no epidemiologicalof no epidemiological

significancesignificance

African water buffalo


GiraffesGiraffes

ElephantsElephants




ArmadillosArmadillosArmadillos are not only Armadillos are not only

susceptible but are susceptible but are

capable of transmitting the capable of transmitting the

disease to each other and disease to each other and

possibly to other speciespossibly to other species

USAHA Proceedings 1974:USAHA Proceedings 1974:

““Clinical and serological response of the NineClinical and serological response of the Nine--banded armadillo (banded armadillo (DasypusDasypus

novemcinctusnovemcinctus) to viruses of African Swine Fever, Hog Cholera, Rinderpest ) to viruses of African Swine Fever, Hog Cholera, Rinderpest

Vesicular Exanthema of Swine, Vesicular Stomatitis and FootVesicular Exanthema of Swine, Vesicular Stomatitis and Foot--andand--mouth mouth

diseasedisease””



HedgehogsHedgehogs

NutriaNutria

CapybarasCapybaras

Rats, Mice andRats, Mice andGuinea pigs can Guinea pigs can be infected be infected

experimentallyexperimentally Capybara

http://www.hedweb.com/animimag/capybara.htm



Not seen in oddNot seen in odd--toedtoed

animals such as animals such as

horses, zebras or rhinoshorses, zebras or rhinos


Old World CamelOld World Camel

is resistant to is resistant to

natural infectionnatural infection



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EtiologyEtiology





Diagnosis Diagnosis



IncubationIncubation

Incubation period depends on which strain of Incubation period depends on which strain of

FMD virus (7 serotypes), dosage, FMD virus (7 serotypes), dosage,

and the route of entry.and the route of entry.

As short as As short as 22--3 days3 days in close contactin close contact

As long as As long as 1010--14 days14 days from windborne infection

Experimentally shown to be as short as 18Experimentally shown to be as short as 18--24 24

hours hours


Minimum doses of FMD virus to Minimum doses of FMD virus to

initiate infectioninitiate infection

RespiratoryRespiratory OralOral

Route RouteRoute Route

CattleCattle 1212 TCID50 1X 101X 106 6 TCID50

PigsPigs 2020 TCID50 8X 108X 1033TCID50

SheepSheep 10 10 TCID50

ImpalasImpalas 11 TCID50


PathogenesisPathogenesis

Most animals acquire virus usually by Most animals acquire virus usually by

inhalationinhalation

Humans and pigs are more susceptible to Humans and pigs are more susceptible to

infection by oral routeinfection by oral route


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Foot-and-mouth blisters on a pig's snout


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PathogenesisPathogenesis

Virus replication in respiratory epithelium Virus replication in respiratory epithelium

and lymphoid tissueand lymphoid tissue

In domestic ruminants pharynx and dorsal In domestic ruminants pharynx and dorsal

soft palate are predilection site for soft palate are predilection site for

replication of FMDvreplication of FMDv

Virus persists there for prolonged periodsVirus persists there for prolonged periods


Replication in lymphoid tissue, tonsils Replication in lymphoid tissue, tonsils

mucosa of soft palatemucosa of soft palate

Virus can be recovered from Virus can be recovered from

retropharyngeal, mandibular, and parotid retropharyngeal, mandibular, and parotid

lymph nodes in more than 50% of cattle in lymph nodes in more than 50% of cattle in

prepre--viremic stageviremic stage


High virus levels may occur in organs and High virus levels may occur in organs and

tissues which do not generally develop tissues which do not generally develop

gross changes including unaffected skin gross changes including unaffected skin

areasareas


Characteristic Blister FormationCharacteristic Blister Formation

Epithelial lesions of FMD are initiated by Epithelial lesions of FMD are initiated by

infection of single cells in the stratum infection of single cells in the stratum

spinosum. spinosum.

Following infection, Following infection, bullaebullae develop by develop by lysislysis

of cell swollen by degeneration and of cell swollen by degeneration and

release of intracellular fluid or focal release of intracellular fluid or focal

intercellular edemaintercellular edema

BullaeBullae coalesce and rupturecoalesce and rupture


Characteristic Blister FormationCharacteristic Blister Formation

Development of characteristic vesicular Development of characteristic vesicular

lesions depends on 2 factors: lesions depends on 2 factors:

–– Infection of epitheliumInfection of epithelium

–– Persistent local irritation or frictionPersistent local irritation or friction


This explains why the mouth, feet and This explains why the mouth, feet and

teats are predilections sites for blisters teats are predilections sites for blisters

in cattle; in cattle;

the dorsum of the snout in pigs from the dorsum of the snout in pigs from

snuffling, snuffling,

on the knees of warthogs that kneel on the knees of warthogs that kneel

when feedingwhen feeding



EtiologyEtiology





Diagnosis Diagnosis



General Clinical SignsGeneral Clinical Signs



Vesicles and erosions in the mucosa of Vesicles and erosions in the mucosa of

the mouth, and skinthe mouth, and skin--hoof junctionhoof junction

Excessive salivationExcessive salivation

LamenessLameness



ListlessListless

Lifting feet alternatelyLifting feet alternately

Lameness Lameness

Clear nasal discharge Clear nasal discharge progressing to progressing to mucopurulent mucopurulent



Blisters in the mouthBlisters in the mouth

Blisters on the muzzleBlisters on the muzzle

Blisters on the tongueBlisters on the tongue

Excessive SalivationExcessive Salivation


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Clinical Signs in CattleClinical Signs in Cattle

Fever (103Fever (103°°--106106°°F)F)

DepressionDepression

AnorexiaAnorexia

Milk production Milk production

ceasesceases

Blisters start to form Blisters start to form

in the mouth in the mouth

Excessive ropy, Excessive ropy,

viscous salivationviscous salivation

Blisters rupture within Blisters rupture within

24 hrs leaving raw, 24 hrs leaving raw,

painful ulcerspainful ulcers

Mouth lesions usually Mouth lesions usually

heal in 10 heal in 10 -- 14 days14 days



Feet

Inter-digital space

Coronary band

Teats

Blisters form on:

Mouth Tongue

Dental pad

Gums

Soft palate

Muzzle

Nostrils



Body tremors from Body tremors from

painpain

Lameness from Lameness from

developing lesions developing lesions

on feeton feet



Lameness

•Coronary band lesion

first appears blanched

•Blisters form between

the digits

•Stamping and shaking

of feet

•Trembling



Smacking of the lips Smacking of the lips

and sucking of the and sucking of the

sore tongue is sore tongue is

characteristiccharacteristic

Secondary Bacterial Secondary Bacterial

infectionsinfections

Mastitis Mastitis ––permanent permanent

damage to udderdamage to udder

Pregnant cows may Pregnant cows may

abortabort


Progression of diseaseProgression of disease

Blisters at infection site initially appear as Blisters at infection site initially appear as

blanched area in the epitheliumblanched area in the epithelium

Area fills with serous fluid forming a Area fills with serous fluid forming a

vesiclevesicle

Vesicles enlarge and coalesceVesicles enlarge and coalesce

Vesicles crack or rupture leaking fluidVesicles crack or rupture leaking fluid

The epithelium necroses off leaving raw The epithelium necroses off leaving raw

ulcer or erosionulcer or erosion



Grey Grey fibrinousfibrinous coating forms over lesionscoating forms over lesions

The coating becomes discolored, yellow, The coating becomes discolored, yellow,

brown, greenbrown, green

As epithelium is restored, lines of As epithelium is restored, lines of

demarcation are evidentdemarcation are evident

Sometimes but not always, permanent Sometimes but not always, permanent

scars formscars form



When blisters are present, cattle salivate When blisters are present, cattle salivate

profusely with ropy viscous material profusely with ropy viscous material

hanging from mouthhanging from mouth

Also see severe Also see severe lacrimationlacrimation and nasal and nasal

dischargedischarge

When vesicles rupture, fever ends When vesicles rupture, fever ends

followed by end of viremiafollowed by end of viremia

Start to finish, signs last 15Start to finish, signs last 15--30 days.30 days.



Recovered animals are permanently Recovered animals are permanently

unthriftyunthrifty


Aging lesions in cattleAging lesions in cattle

Day One

Formation of fluid-filled blister, or vesicle

2 mm-10 cm on the dorsal surface of the tongue



Day Day

FourFour

Day Day

SixSix

Salivation increases as vesicles form and

rupture. Symptoms increase in intensity.



Lines of demarcation

Days 8Days 8--1414

Animals may recover in

2 weeks. Only 1-5%

die from FMD

High morbidity,

Low mortality


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Morbidity approaches 100% in a Morbidity approaches 100% in a

susceptible herd. susceptible herd.



Low MortalityLow Mortality

Rarely fatal except in young animalsRarely fatal except in young animals

Extra-epithelial

replication limited to

myocardium,

immature animals only

USDAUSDA



Young calves may die Young calves may die

without showing any without showing any

clinical signsclinical signs


In young animals there is focal necrosis In young animals there is focal necrosis

of cardiac muscle. of cardiac muscle. ““Tiger heartTiger heart””

5050--80% 80% youngyoung animals die (calves, lambs, etc)animals die (calves, lambs, etc)

USDAUSDAUSDAUSDA


RecoveryRecovery

Recovered animals are Recovered animals are ““poor doerspoor doers””


“More than 200 cows infected in Cambodian

foot-and-mouth disease outbreak”

Time is GMT + 8 hours

Posted: 25-Jul-2005 12:19 hrs

A cow stands on a bank of the Tonle Sap River.

More than 200 cattle in Cambodia have been infected with foot-and-mouth disease since an outbreak last month northwest of the capital, but havesince recovered. http://www.todayonline.com/articles/63247.asp

Recovery


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Water buffalo can be carriers for 5 yearsWater buffalo can be carriers for 5 years


Clinical Signs in SwineClinical Signs in Swine

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Mastitis Mastitis Blisters on teats and udders



Pigs –Reluctance to

move, painful toes


Clinical Signs in Sheep and Clinical Signs in Sheep and

GoatsGoats

•Vesicles on dental pad and between toes•Prone to develop secondary foot-rot

•Lamb death, 50-90%

•Sheep can be carriers for up to 9 months


Clinical Signs in Sheep and GoatsClinical Signs in Sheep and Goats

When sheep or goats become infected with FMD, the disease may

notnot be diagnosed for a considerable time because the clinical signs may be very mild.


Sheep may appear healthy but will be

producing infectious aerosols or spreading

the virus via urine, feces or direct contact.


Lesions in giraffeLesions in giraffe



EtiologyEtiology





Diagnosis Diagnosis



TransmissionTransmissionAerosols/Airborne, Inhaled Aerosols/Airborne, Inhaled

Direct or indirect contactDirect or indirect contact--droplets, droplets,

IngestionIngestion

Artificial InseminationArtificial Insemination

Vectors (vehicles, equipment, or humans)Vectors (vehicles, equipment, or humans)

Carrier stateCarrier state



Aerosol

Spread of aerosols from infected animals, given the right temperature and humidity can travel 250km on the wind

Aerosols transmission via dust storms in Africa spread FMD to England



Airborne on the windAirborne on the wind

Airborne from burning Airborne from burning

pyres suspectedpyres suspected

Airborne from infected Airborne from infected

milk transportmilk transport



Sheds 400,000,000 virus

particles per day

Aerosol droplets spread from infected animal

Only takes 10-12virus particles to

infect one cow



Direct or indirect contact with infected animals

If infected feral hogs come into contact with domestic livestock in the US, it will affect the whole world!



Foot and mouth disease Foot and mouth disease

virus can be transmitted virus can be transmitted

via: via:

Milk Milk

Semen Semen

Saliva Saliva

FecesFeces

UrineUrine

BreathBreath

“Supersoaker fights on the dairy farm”



Ingestion- Feeding contaminated garbage (meat, milk, glands, bones, cheese, etc)

Intraocular

Artificial insemination, or natural reproduction


Vectors

Contact with contaminated objects (equipment, footwear, clothing)


Transmission by humansTransmission by humans

A person in contact with infected animals may retain and exhale virus for up to 36 hours and serve as source of infection.

Humans serve as a mechanical vector when moving from infected animals to susceptible animals.



Birds can be mechanical vectors and can pass Birds can be mechanical vectors and can pass

viable FMD virus after ingestion, but are not viable FMD virus after ingestion, but are not

considered a factor in the spread of the diseaseconsidered a factor in the spread of the disease


Birds can also be infected with FMD virus and shed virus in feces


Courtesy Maryland Dept of Agriculture Public Affairs

www.skysailing.com/ images/nzcropduster.jpg

Intentional act ofBioterrorism

Effective if humidity is

>60%

Can travel 60km overland

or 300km over water



EtiologyEtiology





Diagnosis Diagnosis



DiagnosisDiagnosis

Serum neutralization testSerum neutralization test

Complement fixation testComplement fixation test

EnzymeEnzyme--linked linked immunosorbentimmunosorbent assayassay

Field diagnosisField diagnosis


FMD TestingFMD Testing

TissuesVesic. FluidProbangSwab

Virus isolationVirus isolation

>> 7days7daysRTRT--PCRPCR

6 hr6 hrRealtimeRealtime PCRPCR

2 hr2 hr

Virus ID

Electron Microscopy

TissuesVF

AgAg--ELISAELISA

5 hr5 hr

CFCF--AgAg

3hr3hr


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EtiologyEtiology





Diagnosis Diagnosis




As a vesicular type disease:As a vesicular type disease:

–– Vesicular stomatitis, Vesicular stomatitis,

–– swine vesicular disease of pigs, swine vesicular disease of pigs,

–– vesicular exanthema of pigsvesicular exanthema of pigs



Based on ulcerative lesions in the mouth Based on ulcerative lesions in the mouth

or on the muzzle:or on the muzzle:

–– BVD/MDBVD/MD

–– MCFMCF

–– Bluetongue and other Bluetongue and other orbivirusesorbiviruses

–– LSDLSD

–– IBRIBR

–– RinderpestRinderpest



Based on foot lesions:Based on foot lesions:

–– DermatophilosisDermatophilosis

–– FootFoot--rotrot

–– MCFMCF



Vesicular StomatitisVesicular Stomatitis

Bovine Bovine MammilitisMammilitis

Bovine Viral DiarrheaBovine Viral Diarrhea

Bovine Bovine PapularPapular StomatitisStomatitis

Mucosal Disease (foot Mucosal Disease (foot

lesions)lesions)

Infectious Bovine Infectious Bovine

RhinotracheitisRhinotracheitis

RinderpestRinderpest

Bluetongue (foot lesions)Bluetongue (foot lesions)

Peste des Petits Peste des Petits

RuminantsRuminants

Foot RotFoot Rot

Chemical IrritantsChemical Irritants

Swine Vesicular DiseaseSwine Vesicular Disease

Vesicular Exanthema Vesicular Exanthema --

swineswine


FMD or VS?FMD or VS?

CannotCannot

distinguishdistinguish

clinicallyclinically


FMD FMD vsvs VSVS

VS is not as contagious as FMD VS is not as contagious as FMD

FMD does not affect horsesFMD does not affect horses

VS VS -- Domestic animals are probably not primary Domestic animals are probably not primary hosts.hosts.

VS VS -- VectorVector--borne disease.borne disease.

VS VS -- No effective vaccines available in US.No effective vaccines available in US.

VS VS -- Requires specific ecological conditions.Requires specific ecological conditions.

VS VS -- Infects large number of wild species.Infects large number of wild species.

Both are zoonotic diseases Both are zoonotic diseases


Rapid spread of foot-and-mouth disease world-wide….

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Foot-and-Mouth DiseaseDistribution and Recent Activity

PresentPresentPresentPresent

Recent ActivityRecent ActivityRecent ActivityRecent Activity

FreeFreeFreeFree

1999 2000 2001(Rev. 5-05-01)


Images AcknowledgementImages Acknowledgement

Capybaras: David Pearce, BLTC Research, Capybaras: David Pearce, BLTC Research,

http://www.hedweb.com/animimag/capybahttp://www.hedweb.com/animimag/capyba

ra.htm accessed 8/22/06ra.htm accessed 8/22/06..


Image Watermark Image Watermark

““KAWKAW”” images by Dr. Ken A. Waldrupimages by Dr. Ken A. Waldrup

““MvanVuurenMvanVuuren”” images used with images used with

permission by Dr. Moritz van Vuurenpermission by Dr. Moritz van Vuuren

““LLoganLLogan”” images by Dr. Linda Loganimages by Dr. Linda Logan

““SuzSuz”” images by Dr Suzanne Burnhamimages by Dr Suzanne Burnham

““USDAUSDA”” images by staff at PIADCimages by staff at PIADC


BibliographyBibliography

Committee on Foreign Animal Diseases of the United States AnimalCommittee on Foreign Animal Diseases of the United States AnimalHeath Association, Heath Association, ““Foreign Animal DiseasesForeign Animal Diseases”” 1992, Ch. Vesicular 1992, Ch. Vesicular Diseases, p. 368Diseases, p. 368--382.382.

W. A. W. A. GeeringGeering, , et.alet.al, Exotic Diseases of Animals: a field guide for , Exotic Diseases of Animals: a field guide for Australian veterinarians, 1995, Ch FootAustralian veterinarians, 1995, Ch Foot--andand--mouth disease, p.112mouth disease, p.112--131131

Ninth Edition of Merck Veterinary ManualNinth Edition of Merck Veterinary Manual

M. Van Vuuren, FootM. Van Vuuren, Foot--andand--mouth Disease, an Overview, University of mouth Disease, an Overview, University of Pretoria 2005, Presentation given at Knoxville, Tenn. FEAD coursPretoria 2005, Presentation given at Knoxville, Tenn. FEAD course.e.

Thomson, G. R. and Thomson, G. R. and BastosBastos, A. D. S. , A. D. S. ““FootFoot--andand--mouth diseasemouth disease”” Ch 125 Ch 125 of Infectious Diseases of Livestock, Volume 2. Ed. J. A. W. of Infectious Diseases of Livestock, Volume 2. Ed. J. A. W. CoetzerCoetzerand R. C. Tustin. Oxford University Press, second edition, 2004,and R. C. Tustin. Oxford University Press, second edition, 2004,13241324--1365.1365.


BibliographyBibliography

Tomasula, P.M. and R.P. Tomasula, P.M. and R.P. KonstanceKonstance. . ““The Survival of FootThe Survival of Foot--andand--Mouth Mouth

Disease Virus in Raw and Pasteurized Milk and Milk ProductsDisease Virus in Raw and Pasteurized Milk and Milk Products””..

Journal of Dairy Science, Journal of Dairy Science, 2004; 87:11152004; 87:1115--1121. 1121.

Callis, J.J. et al. Callis, J.J. et al. ““FootFoot--andand--mouth Disease mouth Disease –– A ReviewA Review””. . JAVMA,JAVMA, 1968; 1968;

153:12, 1798153:12, 1798--1802.1802.

Musser, J.M.B. Musser, J.M.B. ““A practitionerA practitioner’’s primer on foots primer on foot--andand--mouth diseasemouth disease””. .

JAVMA, JAVMA, 2004; 224:8, 12612004; 224:8, 1261--1268.1268.

AlexandersenAlexandersen, S., et al. , S., et al. ““The Pathogenesis and Diagnosis of FootThe Pathogenesis and Diagnosis of Foot--andand--

Mouth DiseaseMouth Disease””. . J. Comp. Path. J. Comp. Path. 2003; 129:12003; 129:1--36.36.

O.I.E.O.I.E.

USDA, APHIS, VS, The Grey Book. And associated websites.USDA, APHIS, VS, The Grey Book. And associated websites.

Personal interviews with Dr Logan, Dr McKenna, Dr Personal interviews with Dr Logan, Dr McKenna, Dr CoetzerCoetzer, Dr , Dr

VanVuurenVanVuuren and Dr Waldrupand Dr Waldrup



AcknowledgementsAcknowledgementsSpecial thanks to Special thanks to

Linda Logan, DVM PhDLinda Logan, DVM PhD

Ken Waldrup, DVM PhDKen Waldrup, DVM PhD

Jeffrey Musser, DVMJeffrey Musser, DVM

Professor Moritz van VuurenProfessor Moritz van Vuuren

Kelsey PohlerKelsey Pohler-- Research AssistantResearch Assistant

Charles Swanson Charles Swanson -- Dairy Science studentDairy Science student

Joe Stevens Joe Stevens –– Dairy Science studentDairy Science student

Tom McKenna, DVM PhDTom McKenna, DVM PhD

Corrie Brown, DVM PhDCorrie Brown, DVM PhD

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