I love maths. To me, maths mean « black or white », « true or false ». It rhymes with certainty. Predictability. Exactitude. Music to my ears, definitely ! Because I work in the field of biology where, very often, it is literally the opposite. Oh, don’t get me wrong, I’m not complaining here ; I love what I do ! But wouldn’t it be nice sometimes to be able to use maths to bring a certain amount of certainty in this field ?
I must admit I am trying. Nearly on a daily basis ! Let me give you an example : last week I got an interesting question from a breeder. He was wondering if he was overfeeding his pregnant bitch. Let’s see how maths can be used to give an appropriate answer !
Overfeeding the pregnant bitch : a right concern
First you need all the elements to better understand the background problem. Overfeeding your animal during gestation can indeed have consequences :
–> Overfeeding means the bitch is provided with extra-amounts of energy… And energy excess is converted into fat.
–> Extra-fat infiltrates the muscles. Including an extremely important one at the time of parturition : the myometrium (= the muscle part of the uterus).
–> Because of that, overweight / obese bitches can have weaker uterine contractions at the time of parturition.
—> Weaker uterine contractions means prolonged whelping and eventually difficulties to give birth (what we refer to as dystocia in veterinary medicine)
–> Difficulties to give birth = lower neonatal survival rate.
Ok, but then, how can we use maths to address the question ? The answer : using a mathematical model.
Nutrition, gestation… and maths ?!?!
To do that, you need to have a good understanding on how a pregnant bitch should be fed. Don’t hesitate to watch the video below, it will give you all the key elements you need to know on the matter !
The key sentence here is the following « Puppies will gain 70% of their birth weight after day 42 of gestation ».
It means that :
– the body weight of the bitch should not vary that much during this first period from 0 to 42 days of gestation ;
– after day 42, weight gain is gonna be observed. In a somehow linear pattern.
The textbooks of canine nutrition give us the last element we need here : « At the time of whelping, a bitch body weight should increase by approximately 15-25% » .
Estimated body weight of the bitch during gestation
We now have all the elements. We can therefore build the following table :
Table 1 : Estimated body weight of the pregnant bitch during gestation based on her optimal body weight (*Day 63 means just before whelping)
That can give you an idea of what to expect. And if you want to do it for your own bitch ? Download the following excel sheet I created. I will help you for your specific case.
You just need to :
– know your bitch’s optimal body weight ;
– monitor her weigh on a weekly basis after day 42 of gestation
– check with the Excel calculator I provided you with if you are right on track !
The only thing you would need to do is investing in is a good scale (or you can use the one at your veterinary clinic, it will do the trick as well !).
As much as I would like this model to work in any given situation, keep in mind however that this is not absolute. Other factors may play a role in the equation ( especially, the size of the litter ). Remember : this is biology we are dealing with here. Not mathematics !
DR. EMMANUEL FONTAINE 