Blueberry

Blueberries are close to the ideal dog treat. They are dense in antioxidants, particularly anthocyanins, plus phytochemicals and fibre, and they are low in calories. The practical advantage is portioning: a berry is already one bite, so you never have to cut anything and you always know exactly how many you handed over. That makes them one of the few natural treats you can use repeatedly through a long training session without blowing the calorie budget. A reasonable serving is about 5 berries for a small dog and roughly 10 to 15 for a large one, occasionally rather than daily. Beyond that you get loose stool. Keep blueberries and everything else inside 10% of daily calories. Frozen blueberries straight from the freezer bag are a genuinely good hot-weather reward, and the crunch keeps dogs interested. One caveat: a frozen berry is hard, and for a very small dog it is a mild choking risk. Thaw them part way or squash them between your fingers for toy breeds. Where blueberries go wrong is in packaged form. Blueberry muffins, blueberry yogurt, jam, cereal bars and smoothies all add sugar, and some sugar-free products contain xylitol, which US labels sometimes print as birch sugar. Trail mix is the worst offender: dried blueberries in a trail mix usually sit next to raisins, and raisins can cause acute kidney injury in dogs, or next to macadamia nuts, which are also toxic. Feed fresh or plain frozen blueberries only. A few too many berries means loose stool, and cutting back fixes it. But if your dog ate a trail mix or baked good containing raisins or macadamia nuts, or anything whose label lists xylitol or birch sugar, call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 immediately, even if the dog seems fine. Choking on a frozen berry is also an emergency. Do not induce vomiting at home.