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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