An Estimate of the Number of Dogs in US Shelters · shelters in the United States? This sampling...

AnEstimateoftheNumberofDogsinUSShelters

KimberlyA.Woodruff,DVM,MS,DACVPMDavidR.Smith,DVM,PhD,DACVPM(Epi)

Currently….•Nogoverningbodyforsheltermedicine•Nonationallist/registrationofanimalhumaneorganizations

•Nonationalregistration/censusofshelteranimals•Difficulttoestimatetotalnumberofdogsinshelters

Objectives• EstimatetotalnumberofsheltersintheUnitedStates• Brickandmortar• Intake/adoptoutdogs

• EstimatenumberofdogsenteringUSsheltersannuallyandtheiroutcome• Returnedtoowner• Adopted• Transferred• Euthanized

• IdentifycharacteristicsofUSsheltersthatmodifydogmovement.

MaterialsandMethods• Initiallistof10,890animalsheltersANDrescueorganizationsintheUnitedStates• Forinclusion• Mustacceptdogs• Mustadoptdogstothepublic• Brickandmortar

MaterialsandMethods

• Additionalsheltersremovedfor:• notbeingananimalshelter• notashelterfordogs• notadoptingdogstopublic• Duplicates

• FinalSurveyFrame:2,862Sheltersfrom49states

MaterialsandMethods

MaterialsandMethods• Telephonesurvey• Attempttocontacteachof2,862• CallsmadethroughoutJuly,2016• 8attemptspershelterbeforenumberwasretired

•413completesurveys(14.4%)

StatisticalMethods• Factorsassociatedwithnumberofdogsenteringashelterweretestedusingmultivariablelinearregressionwith“shelter”astheunitofinvestigation• Proc MixedSAS

• Factorsassociatedwiththeprobabilityforadoginasheltertobeadopted,transferred,returnedtoowneroreuthanizedweretestedusingmultivariablelogisticregressionwith“shelter”asaclustereffect• Proc GenMod SAS(generalizedestimatingequation)

WhatisthetotalnumberofdogsheltersintheUnitedStates?Thissamplingframe(likeothers)islikelyansubsetofthetruenumberofdogsheltersintheUSIfweknewthetotalnumberofsheltersintheUS,wecouldusethesurveyresultstoestimatethetotalnumberofdogsinsheltersandotherstatisticsAnovelapproachtothisproblemiscapture-recapturemethodology

Capture-recapturemethodology•Usedbywildliferesearcherstoestimatethenumberofanimalsinapopulation•Comparesheltersinourframe(capture)tootherframes(recapture)•E.g.theproportionofsheltersfromMississippiinourframeandalsofoundinanindependentframeofMississippishelters

Capture-recapturemethodologyThesimplestmethodforestimatingpopulationsizeistheLincoln-Petersenmethod.Thebasicmethodinvolvesasinglemarkingandasinglerecaptureepisode.Ifwemarkasampleofanimals,Mandcaptureasampleofanimals,C,containingRmarkedindividuals,weestimatethesizeofthepopulationatthetimeoftheoriginalmarking,N,as:

N=MC/R

Capture-recapturemethodology•WeknowM(2,862).IfwecanestimateC/R,thenwecancalculatethetotalnumberofshelters.

• C=thetotalnumberofsheltersinotherlists• FL,MI,MS,MA,SC

•R=thenumberofrepeats•Clopper-Pearson95%CIaroundR/C

N=MC/R

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

0 400 800 1200 1600 2000 2400 2800 3200 3600 4000 4400

1 201 401 601 801 100112011401160118012001220124012601280130013201340136013801400142014401

Relativ

eFreq

uency

Number

NumberofdogsenteringtheshelterMean:781.9Median:500Max:5500Min:10

NumberofDogsEnteringSheltersVariable Estimate Standard

errorP-Value

Intercept 472.48 118..95

FundingSource

Mixed 500.64 102.27 <.0001

Municipal 424.29 88.42

Private 0

Region Midwest -30.27 122.51 <.001

Northeast -316.69 167.37

Southeast 115.02 129.8

Southwest 500.61 154.73

West 0

AcceptsSurrender

No -415.14 158.28 0.0091

Yes 0

Adoption Transfer ReturntoOwner

Euthanize

Adoption

0.0% 5.0%

10.0% 15.0% 20.0% 25.0% 30.0% 35.0% 40.0% 45.0% 50.0%

0 200 400 600 800 10001200140016001800200022002400260028003000

1 201 401 601 801 1001120114011601180120012201240126012801

Relativ

eFreq

uency

Number

Numberofdogsadopted

Mean:371.4Median:225Max:2750Min:5

DogsExitingFacilitiesthroughAdoption

Variable Estimate Standard Error 95%Confidence Limits P-Value

Intercept 0.88 0.10 0.68 1.08

FundingSource

Mixed -0.53 0.16 -0.83 -0.22 <.0001

Municipal -1.19 0.13 -1.5 -0.93

Private 0 0 0 0

AdmissionType

Limitedadmission

1.01 0.0001 -0.0003 -0.0001 0.0016

Openadmission 0 0 0 0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Mixed Municipal PrivateFundingsource

FundingSource Municipal:OR:0.59(0.44-0.80)Mixed:OR:0.30(0.23,0.39)Private:Referent

Prob

ability

ProbabilityforaSheltertoAdoptaDog

0

0.2

0.4

0.6

0.8

1

No YesStrayAdmission

AdmissionTypeLimitedadmission:OR:2.75(1.46,5.20)Openadmission:Referent

Prob

ability

ProbabilityforaSheltertoAdoptaDog

Transfer

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000

1 201 401 601 801 1001 1201 1401 1601 1801 2001 2201 2401 2601 2801

Relativ

eFreq

uency

Number

NumberofdogstransferredMean:110Median:25Max:1702Min:0

TransferAnalysisofGEE ParameterEstimates

Variable Estimate StandardError

95%ConfidenceLimits

P-value

Intercept -2.50 0.28 -3.04 -1.96

Fundingsource

Mixed 0.47 0.24 -0.01 0.94 0.0017

Municipal 0.73 0.21 0.33 1.13

Private 0 0 0 0

Region Midwest 0.26 0.26 -0.26 0.77 <.001

Northeast -1.62 0.43 -2.45 -0.78

Southeast 0.43 0.27 -0.20 0.96

Southwest 0.20 0.31 -0.44 0.83

West 0 0 0 0

AdmissionType

Limitedadmission

-1.33 0.54 -2.40 0.27 0.014

OpenAdmission 0 0 0 0

Probability foraSheltertoTransferaDog

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Mixed Municipal Private

Prob

ability

FundingSource

FundingSourceMixed:OR:1.59(0.20,2.56)Municipal:OF:2.07(1.39,3.1)Private:Referent

0

0.02

0.04

0.06

0.08

0.1

0.12

MW NE SE SW W

Region

Prob

ability

UnitedStatesRegion

Probability foraSheltertoTransferaDogMidwest:OR:1.29(0.77,2.17)Northeast:OR:0.20(0.09,0.46)Southeast:OR:1.54(0.91,2.60)Southwest:OR:1.22(0.65,2.30)West:Referent

0

0.02

0.04

0.06

0.08

0.1

0.12

No YesStrayAdmission

AdmissionType

Prob

ability

Probability foraSheltertoTransferaDog

LimitedAdmission:OR:0.26(0.09,0.76)OpenAdmission:referent

ReturntoOwner

NumberofDogsReturnedtoOwner

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000

1 201 401 601 801 1001 1201 1401 1601 1801 2001 2201 2401 2601 2801

Relativ

eFreq

uency

Number

Numberofdogsreturnedtoowner

Dogsreturnedtoowner

Variable Estimate StandardError

95% ConfidenceLimit P-Value

Intercept -1.41 0.15 -1.70 -1.12

FundingSource

Mixed 0.78 0.15 -1.09 1.09 <0.0001

Municipal 1.22 0.12 1.47 1.47

Private 0 0 0 0

Region Midwest -0.53 0.12 -0.30 -0.30 <0.0001

Northeast -0.98 0.27 -0.45 -0.45

Southeast -1.44 0.16 -1.31 -1.13

Southwest -0.93 0.15 -0.62 -0.62

West 0 0 0 0

AdmissionType

Limited Admission -1.74 0.49 -0.78 -0.78 0.005

OpenAdmission 0 0 0 0

ShelterSize

-0.0001 0 -0.0002 0 0.0051

ShelterSize• OR:0.99(0.98,1)

• Thelargerthefacility(greaternumberofdogs),thelesslikelythatthefacilitywillreturnadogtoowner.

ProbabilityforaDogtobeRTO

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

Mixed Municipal Private

Prob

ability

FundingSource

FundingSourceMixed:OR:2.22(1.65,2.99)Municipal:OF:3.40(2.67,4.34)Private:Referent

00.020.040.060.080.10.120.140.160.180.2

MW NE SE SW W

Prob

ability

Region

RegionMidwest:OR:0.59(0.47,0.74)Northeast:OR:0.38(0.22,0.64)Southeast:OR:0.24(0.18,0.32)Southwest:OR:0.40(0.29,0.53)

ProbabilityforaDogtobeRTO

ProbabilityforaDogtobeRTO

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

No Yes

Prob

ability

StrayAdmittance

AdmissionType

Limitedadmission:OR:0.18(0.07,0.46)OpenAdmission:Referent

Euthanized

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000

1 201 401 601 801 1001 1201 1401 1601 1801 2001 2201 2401 2601 2801

RelativeFreq

uency

Number

Numberofdogseuthanized

Mean:109.8Median:7Max:2622Min:0

AnimalsEuthanizedinShelters

Variable Estimate StandardError

95%ConfidenceLimits

P-value

Intercept -4.29 0.38 -5.03 -3.55

FundingSource

Mixed 0.35 0.46 -0.53 1.25 <.0001

Municipal 0.76 0.44 -0.10 1.62

Private 0 0 0 0

Region Midwest 0.49 0.24 0.03 0.95 <.0001

Northeast 0.33 0.56 -0.77 1.4

Southeast 1.63 0.22 1.20 2.06

Southwest 1.13 0.28 0.57 1.69

West 0 0 0 0

AdmissionType LimitedAdmission

-1.90 -3.27 -3.27 -0.54 0.006

OpenAdmission

0 0 0 0

Shelter Sixe 0.0005 0.0001 0.0003 0.0006 <.0001

ShelterSizeOR:1.0005(1.0003,1.0006)

Thelargertheshelterintake,themorelikelytheyaretoeuthanize.

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

Mixed Municipal Private

Prob

ability

FundingSource

FundingSource Mixed:OR:1.42(0.58,3.348)Municipal:OR:2.13(0.90,5.07)Private:OR:1(1,1)

ProbabilityforaSheltertoEuthanizeaDog

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

MW NE SE SW WRegion

Region Midwest:OR:1.62(1.03,2.59)Northeast:OR:1.39(0.46,4.19)Southeast:OR:5.1(3.32,7.87)Southwest:OR:3.09(1.77,5.40)West:Referent

Prob

ability

ProbabilityforaSheltertoEuthanizeaDog

ProbabilityforaSheltertoEuthanizeaDog

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

No Yes

Prob

ability

StrayAdmittance

AdmissionType LimitedAdmission:OR:0.14(0.08,0.59)OpenAdmission:referent

ClientFrame

OtherFrames Repeats Simple Unbiased

State M C R totalshelters

Florida 97 131 67 190 189

SouthCarolina 52 143 47 158 158

Maine 21 59 13 95 93

Michigan 101 140 66 214 214

Mississippi 35 66 25 92 92

All 306 539 218 757 756

R/C=218/539=0.40(95%CI=0.36-0.45)

NumberofDogShelters• 7,076(95%CI=6,399-7,890)

NumberofDogs• Enteringshelters:5,532,904(95%CI:5,003,528-6,169,579)• Adopted:2,628,112(95%CI:2,376,660-2,930,531)• ReturnedtoOwner:969,443(95%CI:876,689-1,080,998)• Transferred:778,385(95%CI:703,911-867,955)• Euthanized:776,970(95%CI:702,631-866,377)

NumberofDogs TotalNumber Lower95% CI Upper95% CI

Shelters 7,076 6,399 7,890

TotalDogs 5,532,904 5,003,528 6,169,579

Adopted 2,628,112 2,376,660 2,930,531

Returned toOwner 969,443 876,689 1,080,998

Transferred 778,385 703,911 867,955

Euthanized 776,970 702,631 866,366

NumberofDogs…

2,628,11047%

776,97014%

969,44318%

778,38514%

379,9947%

AdoptedEuthanizedReturnedTransferredOther

NumberofDogs MississippiState ASPCA HSUS

Totalshelters 7,076 13,600 3,500

TotalDogs 5,532,904 3.9 million NA

Adopted 2,628,112 1.4million NA

Returned toOwner 969,443 542,000 NA

Transferred 778,385 NA NA

Euthanized 776,970 1.2million NA

Conclusion

ThereareseveralvariablesthataffectthenumbersandfatesofdogsenteringsheltersacrosstheUnitedStates• Region• Fundingsource• AdmissionType• Numberofintakes

Conclusion

Whydowecare?• Understandpetpopulationdynamics

• Transportprogram• Managementpractices/policies• Systemdynamics

• Identifyingtrendsindognumbersinanimalshelters