The DWR said big game animals are vulnerable and weak in the spring after a lack of food over the winter.
Unleashed dogs may act on instinct to chase deer and other big game. Wildlife officers say that can be harmful for deer and other animals in survival mode that afford to waste energy.
DWR Big Game Coordinator Dax Mangus said wildlife typically move to lower elevations and south-facing slopes for new vegetation. That can bring them closer to roads and other populated urban areas.
Big game can be found in national forests, and while pets are allowed, they must be kept on a leash no longer than six feet in developed recreation areas and on trails.