Awww..cute doggies. I haven't personally knitted a dog sweater but I can tell you that in my pre-knitting days I bought some pricey hand-knitted sweaters for our two medium sized dogs (40 and 50 pounds). We live in Truckee, California, which often has the US's coldest morning temps in the winter (today the low was -9). Did the sweaters stay on the dogs? For maybe 2 minutes! Once she rid herself of the sweater, the smaller dog snatched it up and ran off into the woods with it, and it was never seen again!
We still have one of those thankless animals, and a new furbaby who is a black lab mix, and needless to say, I'm not in a hurry to knit anything for them, lol!