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Effects of Phenotypic Characteristics on the Length of Stay of Dogs at Two No Kill Animal Shelters

Brown W, Davidson J, and Zuefle M.  (2013) Effects of Phenotypic Characteristics on the Length of Stay of Dogs at Two No Kill Animal Shelters, Journal of Applied Animal Welfare Science, (16):2-18.

Research Question:  What effects do certain phenotypic traits of dogs (breed, size, color, age, sex) have on their length of stay (LOS) at two no-kill animal shelters in New York?

Subjects:  Subjects in this study were 1063 dogs and puppies adopted from the Tompkins County Society for Prevention of Cruelty to Animals (TCSPCA) in Ithaca, New York between January 2008 and May 2011, and 203 dogs and puppies adopted from the Humane Society of Yates Country (HSYC) in Penn Yan, New York between January 2008 and February 2010.

Methodology:  Adoption records that included intake date, adoption date, estimated breed or mix, estimated or known age, coat color, and sex were collected on all subjects.  Length of stay (LOS) was calculated in days as the difference between the intake date and the date that the adoption paperwork was signed.  Two dogs stayed at the shelter for more than 18 months.  These two dogs were considered outliers and not used in the study, leaving a total of 1,264 dogs in the study.  These dogs were grouped into the following categories:

  1. Age: puppies less than or equal to 6 months, puppies older than 6 months but less than 12 months, adults 1-3 years old, adults 3-6 years old, adults 6-9 years old, adults older than 9 years.
  2. Size: XS (2-10 lb), S (10-30 lb), M (30-55 lb), L (55-90 lb), XL (> 90 lb).
  3. Breed: Sporting, Hound, Guard, Terrier, Lap, Companion, Herding, Spitz, Bully, Giant.
  4. Color: Light (any combination of gray, white and yellow), Medium (combinations of tan, red, brindle, tri-colored, and combinations of any light color with these), Dark (combinations of black and brown or any medium color with black or brown).

Statistical differences in LOS among the different categories, as well as interactions among the categories, were determined using analysis of variance (ANOVA).  A t-test was used to look for a difference in LOS between the sexes.

Findings:  The mean LOS for all 1,264 dogs was 34.6 days.  The average LOS for puppies less than 1 year old (n = 546) was 23.9 days, which was significantly shorter than it was for adult dogs aged 1 year and older (n = 706) at 42.7 days.  This is consistent with findings from previous studies, which have shown that puppies tend to stay at shelters for less time than adult dogs.  Results also showed that for adult dogs, the length of stay increased approximately 1day for each year of age.  Size also had an influence on LOS.  XS dogs had the shortest mean LOS at 33.4 days, and M dogs had the longest mean LOS at 48.9 days.  LOS was also influenced by breed.  Giant breeds had the shortest mean LOS at 20.8 days and guard breeds had the longest mean LOS at 59.8 days.  There was no significant difference in LOS between the sexes for either puppies or adult dogs, nor was there a significant difference in LOS based on coat color.  No significant interactions were noted.

Limitations:  This study was conducted at two no-kill shelters in New York.  More studies need to be done to account for regional preferences in different geographic locations, as well as differences in the LOS at traditional shelters.

Summary by Traci Raley, MS

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