Ensure for dogs?

My older dog is losing weight and hair, increasing her food (senior diet) is not helping her to gain weight. Can I give her dietary supplements, like Ensure, that people use?

You need to take your senior dog to a vet for a geriatric examination. There are many medical conditions that can cause these symptoms in an older dog, some of them serious. I would urge you not to give your dog any thing like ensure, as that can make the situation worse and make your dog sick(er).

Really? When you feel yourself saying something stupid and obvious like "You should take your dog to a vet" in response to a post like this please check yourself. Let's just all assume every message ever written starts with "You should really take your dog to a vet but..."
   
Does anyone have any HELPFUL advice about giving a dog Ensure?