Behavioral, social, and hormonal outcomes of dogs rescued from canine commercial breeding establishments

Across species, early life experiences play an imperative role in shaping physiological, behavioral, and psychological processes. Past research has suggested that dogs reared and maintained in adverse and socially deprived environments, like commercial breeding establishments (CBEs, aka puppy mills), demonstrate multiple behavioral and psychological abnormalities, but observational studies have yet to be conducted. We explored differences in the behavior and cortisol levels of dogs rescued from CBEs during social interactions with humans. Twenty dogs (8 CBE, 12 other backgrounds) currently residing at Hearts United for Animals sanctuary were observed while interacting with an unfamiliar researcher and then tested on a food-based pointing task. Salivary cortisol levels were assessed at three time points. Initial analyses revealed that CBE dogs showed lower levels of human-directed social behavior, including a longer latency to initiate contact (p=.04) and look at the researcher (p=.03), and exhibited more fear- related behavior, including spending more time in a crouched position (p=.02) and less time in locomotion (p=.03). CBE dogs were less likely accept food from the researcher (p=.02), so their ability to follow social cues to locate hidden food items could not be assessed. Differences in cortisol levels will be discussed, though nearly half of the CBE dogs did not produce enough saliva to assay, perhaps due to heightened stress (i.e., sympathetic suppression of digestive functions). These findings shed light on the deleterious effects of adverse living conditions on dogs’ social, behavioral, and physiological wellbeing, and elucidate the difficulties they face in forming positive social relationships with humans