PS6-25. Dogs' Daily Activity Patterns Change with Age.

Abstract Dogs’ physiology changes as they age. These changes are accompanied by behavioral shifts, such as changes in dogs’ activity levels and daily activity rhythms. This study aimed to explore how large dogs’ daily patterns of activity change as they age. Forty-eight Labrador Retrievers (26 male, 22 female), from 1 to 14 years of age, were randomly selected from Four Rivers Kennel’s existing research colony according to their age. Dogs were fed once a day; amount of food consumed was determined by weighing food offered and recording weight of orts. 24-hour activity was monitored via Actical collar accelerometers and collected across two days. Dogs were individually housed with access to outdoor socialization yards for 6-8 hours per day, weather permitting. While in kennels, dogs were exposed to natural lighting via windows. Overnight activity was estimated using data from 6pm to 6am. The times dogs were let out and brought in were recorded to determine indoor and outside activity. Data were analyzed in SAS using a general linear model. As most dogs were kept inside at least one day due to cold temperatures, the first 24-hour period recorded where the dog was let outside during the day was used for analysis. Sex and age*sex interaction had no effect on activity parameters. Total activity counts decreased with age (P < 0.0001, R2 = 0.46). Outside and inside activity counts also decreased with age (P ≤ 0.0002, R2 = 0.38 and 0.26, respectively). While daytime activity followed a similar pattern (P < 0.0001), total nighttime activity did not change with age (P = 0.90). Nighttime activity did become more variable with age, and greater ranges of nighttime activity counts were observed as age increased. When looking at nighttime activity as a percentage of total activity, more of old dogs’ activity occurred at night, while younger dogs were more active during the day (P = 0.01, R2 = 0.14). Our results suggest that as dogs age, their overall activity may decline, but they also become more restless at night.