Mammalian growth and development is really fascinating. Last week– last Monday– I picked each of them up and stepped on the scale. They both weighed in at 41 lbs. This week, the density that is Rocky asked not to be picked up; Missy was o.k. with it. She’s gained three pounds and is approximately* seven inches longer (base of tail to ear) than he.
[*I say approximately because it’s not easy measuring dogs using a bathroom scale and fold-out measuring stick. I thought a regular pull out carpenters’ tape would freak them out.]
(Gompertz curve graph from S. K. Helmink, R. D. Shanks and E. A. Leighton, “Breed and sex differences in growth curves for two breeds of dog guides,” 2000, Journal of Animal Science: 78:27-32. Link.)
I did not look carefully at the Methods section of this paper. I’ve seen enough Gompertz curves in my day to know it looks about right.
At 165 days (give or take), and 20kg, Missy appears to be tracking right there between female German Shepherd dog and female Lab– the smaller two of the four curves. (I know, it’s hard to see the curve for male Labs– the largest of the four sex*breed curves.) I’ll keep weighing on a weekly basis, but at first glance it looks like Missy might reach adult size between 55-60 pounds when she’s about a year old.
The version of the paper that I’m looking at (see link above) does not provide information about how the study was funded. My guess is, “your tax dollars at work.” The authors’ final thoughts:
Implications The construction of growth curves for male and female German shepherd dogs and Labrador retrievers at the Seeing Eye provides information about the average mature weight and the average growth term for the dogs in this population. These ﬁndings may be used to aid in development of a selection protocol to increase the probability that dogs will attain mature weight within the range of 18 to 32 kg.
“Hey, Joe! I just got a < five month old German Shepherd dog, black lab mix from the shelter in West Point. She’s 29 pounds. How big will she get?”
“About 55-60 pounds,” he says. Joe’s the vet. More advise, “No, don’t get three months’ heart worm treatment now. She’ll grow. She won’t be full sized for a few more months.” ~~
I appreciate “scientific” research. I really do. But c’mon.
These ﬁndings may be used to aid in development of a selection protocol to increase the probability that dogs will attain mature weight within the range of 18 to 32 kg.
My hunch is that if you provide adequate nutrition, exercise, and stimulation– including learning boundaries– these dogs are going to attain a mature weight. What was the question?
And what are you going to do with the little big-hearted outlier?