# Trends in Intake, Length of Stay and Outcome Data in a Portuguese Animal Shelter Between 2018 and 2024

## TL;DR

A Portuguese animal shelter study found that early adoption, microchipping compliance, and species-specific strategies are key to reducing overcrowding and improving animal welfare.

## Contribution

The study introduces a data-driven framework for optimizing shelter management through analysis of adoption trends, length of stay, and population balance.

## Key findings

- Adoptions were most successful within the first week, with prolonged stays reducing adoption odds.
- Microchipped animals were 71 times more likely to be returned to owners, but only 9.5% arrived with identification.
- Collaborations with animal protection associations helped place hard-to-place animals, especially seniors and cats.

## Abstract

Overpopulation in municipal shelters is a significant challenge across Europe. This study analyzed 2291 dog and cat admissions to a Portuguese municipal shelter between 2018 and 2024, covering the COVID-19 pandemic. For the 1325 adoptable animals, Length of Stay proved critical: adoptions were most frequent within the first week, while prolonged stays significantly reduced success rates. Although microchipped animals were 71 times more likely to be returned to owners, only 9.5% arrived with identification, revealing low compliance with mandatory law requirements. While the Live Release Rate (79.7%) and Save Rate (84.7%) reflect a strong commitment to life-saving outcomes, a Population Balance Calculation of 75.6% indicates cumulative overcrowding. Collaborations with animal protection associations were vital in finding homes for hard-to-place animals, particularly seniors and cats. These findings highlight the need for early adoption initiatives, improved microchip compliance, and species-specific strategies like Trap-Neuter-Return. This study offers a data-driven framework to guide evidence-based shelter management in Portugal and similar European systems within a One Health perspective.

Municipal animal shelters play a crucial role in rescuing abandoned animals, managing free-roaming populations, and promoting animal welfare. This seven-year retrospective study analyzed 2291 animals (1132 dogs, 1159 cats) admitted to a Portuguese municipal shelter (CVM Feira) between 2018 and 2024 to identify predictors of live outcomes. Descriptive and regression analyses were performed on 1325 adoptable animals. Adoption occurred for 58.9% of these animals, while 41.1% remained in long-term housing, reflecting growing shelter capacity pressures. Length of Stay (LOS) was the strongest predictor of adoption, with extended stays markedly reducing adoption odds and contributing to overcrowding. For dogs, female sex and owner or animal protection association (APA) surrender increased adoption likelihood. Microchipped animals were 71 times more likely to be returned to their owners, although only a small proportion entered the shelter with identification. The overall Live Release Rate (LRR) was 79.7% and Save Rate (SR) 84.7%, highlighting effective life-saving efforts, while the Population Balance Calculation (PBC) of 75.6% revealed challenges in population flow-through. These findings provide evidence that data-driven strategies, including reducing LOS, enforcing microchipping, and applying species-specific management, are essential to optimize municipal shelter operations and improve animal welfare, with insights applicable to broader European and international contexts.