whtsthfrequency:She's 35 lbs, 5 years old, and pretty active (4-5 miles a day, 6+ on weekends, plus inside activities) for a non-working dog. She has never eaten more than ~450 (maybe 500 or so if I add canned) calories a day. But her weight never changes. Her health is perfect. Technically she should be getting almost double that! Just goes to show that every dog is different.
I had a 32 pound Border Collie female that was like that. It's very common in the breed to be either wildly inefficient at energy usage, or extremely efficient - hard keeper and easy keepers and not much between.
I was talking to a vet once who is also a breeder and top level trainer of BCs, and she guesses that it has to do with, first, the origin of the line - the old shepherd's dogs on the hills tended to have hard knock lives and subsisted on very little. Farm dogs, on the other hand, lived off the fat of the land - literally in some ways.
Second, the hard keepers also seem to be "hot" dogs - dogs that expend a lot of energy just sitting, spinning their wheels mentally. These tend to be lines that were strongly bred for competitions, but not necessarily farm work, where being cool is just as important as being quick and mentally agile.
Anyway, Ann came from one of the hard knock, hill lines - she was pretty laid back in the house, though her failing as a sheepdog was that she wanted to play too hard. Even training every day and going for long walks and swims, she burned no more than 550 kcals a day once she matured. It was truly weird to feed her just a smidge more than my 8 pound Chinese Crested dog.
My old Trim dog (BC) was very similar. She was a very very hard worker, but she eats like a bird. She weighed 49 pounds and would get fat, seriously fat, if she got more than 700 kcals a day. Her current handler blesses me every day for giving Trim to her (well, she says she does) and that's one of the reasons. Now she's older, she eats even less! And she's 11 and a 1/2 and still runs about 8 miles a day total full out, clearing runways of migratory birds. She's healthy, 100% free of arthritis, and still plays frisbee until her handler is exhausted, at the end of the day.
Becca Shouse
Maggie and Zhi (queen bees), Ben, Gus, Cord, Rocky, Ted (BCs), Lu and Tully (Maremma flock guardians)
Irena Farm, Semora, NC
