Winter's cold air brings lots of concerns for responsible dog owners.
Adequate shelter is a necessity. Keep your dog warm, dry and away from drafts. Tiles and uncarpeted areas may become extremely cold, so make sure to place blankets and pads on floors in these areas -- preferably in a nice sunny corner. Keep your humidifier humming to prevent static electricity and dry skin (25-30% humidity is a good goal for most homes).
Be extra careful when walking or playing with your dog near frozen lakes, rivers or ponds. Your dog could slip or jump in and get seriously injured.
Never let your dog off the leash on snow or ice, especially during a snowstorm. Dogs frequently lose their scent in the snow and ice and easily become lost.
Your dog needs a well-groomed coat to keep him properly insulated. Brush your dog regularly. (The contrast between the bitter outdoors temperature and the dry heat of indoors can cause your dog to develop dry skin, so don't bathe him as often as you do in the summer.) Long-haired dogs like Newfoundlands should have their paw hair clipped to ease snow removal and the cleaning of their feet.
Apply a thin layer of aloe, petroleum jelly or Pam (the sprayable cooking oil) on your dog's footpads before he heads outside. The oil will help minimize the buildup of ice and snow between toes and if the dog licks his toes, these products are safe.
Thoroughly wipe off your dog's legs and stomach when he comes in out of the rain, snow or ice. Check the sensitive paw pads which may bleed from snow or ice encrusted in them. Salt, antifreeze or other chemicals could harm your dog if he ingests them while licking his paws. Drying and cleaning his paws also helps avoid tiny cuts and cracked pads. (A little petroleum jelly may soften the pads and prevent further cracking.) Towel or blow dry your dog (only on the very low setting and hold the dryer at least eight inches away from him) if he gets wet from rain or snow.
Feed your dog more if he spends a lot of time outdoors. It takes more energy in the winter to keep body temperature regulated, so additional calories are necessary.
If your dog is not active in the winter (because you don't exercise him as much as in other seasons), beware that he doesn't gain weight.
Don't leave your dog alone in a car. It gets too cold and carbon monoxide from an engine left running is dangerous.
Outdoor cats sometimes seek warmth under the hood of cars. Bang loudly on the hood of your car and wait a few seconds before starting the engine -- to give the cat a chance to escape.
Keep a supply of canned/dry pet food with other emergency provisions, as well as plenty of water. In case of inclement weather, power outages or natural disasters, your pet will always have enough food.
If your Newfoundland is sensitive to cold due to age or illness take him outdoors only long enough to relieve himself.