This thread is part of a multi-thread series on hamster nutrition. Originally Parts I, II, III, and IV were originally written as one thread, but were split due to length. For this reason, the guide works best if the threads are read in their numbered order. However this is not strictly necessary, as each thread can stand on its own as well.
Below, you will see a listing of the different threads in the series and links to them:
[HAMSTER NUTRITION I] Nutrition, Variety, and Quality
[HAMSTER NUTRITION II] Food Mixing
[HAMSTER NUTRITION III] Calculating the Guaranteed Analysis of a Mixed Diet
[HAMSTER NUTRITION IV] Commercial Food List
[HAMSTER NUTRITION V] Safe and Unsafe Foods for Hamsters
Credits - Sincere thanks to Christmas_hamster, the creator of the original Master Food List which inspired this project. Next, nebit had an enormous role in developing, editing, and improving these threads. Finally, HoppingHammy and tbiM20 also offered tons of editing, advice, and contributions. Thank you all for your help--this wouldn't have been possible without you!
INTRODUCTION
In the thread Food Mixing you can read what mixing foods is, and why we choose to do it and promote it. As a brief summary--the idea behind mixing different commercial foods is that there is no single food available that is a great diet on its own. Every food has both strengths and weaknesses. The idea with food mixing is to supplement the weaknesses of one food with the strengths of another, so that the resulting mix is a better diet than either of the two mixes started with.
CHALLENGES WITH MIXED DIETS
As you can see above, mixed diets are a great option. However, they do present a challenge. When feeding a single food, it's easy to determine the guaranteed analysis (protein, fat, and fiber) of the food. All you do is look on the bag.
But with a mixed diet, it's a bit more complicated. If you mix Food A and Food B, you will end up with a GA that is different from the GA of either of those foods. How different it is depends on the proportions mixed.
BASIC CONCEPTS
#1. The protein / fat / fiber of a mixed diet will be somewhere "in between" the highest and lowest values given by each individual food. This is just a function of math.
Let's say you have a bag full of marbles. There are exactly 100 marbles in the bag. Some are red, and some are blue. You don't know how many red marbles there are or how many blue marbles there are. But you do know that there are 100 in the bag. There could be 99 red marbles and 1 blue marble. There could be 50 red marbles and 50 blue marbles. There could be 17 red marbles and 83 blue marbles.
Can you have 0 red marbles? No, because we said there are both colors in the bag.
Can you have 150 red marbles? No, because we said there are 100 marbles in the bag.
For example, if you are feeding the following mixes:
Oxbow (15% protein)
Carefresh Complete Menu (17% protein)
Oxbow is the lowest-protein food at 15%. Carefresh Complete Menu is the highest-protein food at 17%. The overall protein value for this mix will be between 15% and 17%. It cannot possibly be below 15%, because there is at least some Oxbow in the mix, which has 15% protein. It cannot be above 17%, because there's no food in the mix that has more than 17% protein.
#2. The higher the percentage of a particular food in your diet, the closer the overall diet's GA will be to that food. In other words, the more of a food you use, the stronger its effect on the overall diet.
Let's say you're feeding two foods called Seed Mix and Lab Block. Seed Mix has 12% protein, and Lab Block has 25% protein. For our first example, you feed mostly Seed Mix (90% of the diet) and just a tiny bit of Lab Block (10% of the diet).
90% Seed Mix + 10% Lab Block
90% Seed Mix in diet * 12% protein + 10% Lab Block in diet * 25% protein =
(0.90*0.12) + (0.10*0.25) =
(0.108) + (0.025) = 0.133
13.3% overall protein
In this first example, the overall protein content is 13.3%. Since so much Seed Mix is being used (90% of the diet), you would expect the overall protein to be closer to the protein of Seed Mix than it is to Lab Block. And it does work out this way - 13.3% is closer to 12% than 25%.
But let's do another example. This time, we use more Lab Block than Seed Mix. We're going to do 90% Lab Block and 10% Seed Mix.
90% Lab Block + 10% Seed Mix
90% Lab Block in diet * 25% protein + 10% Seed Mix in diet * 12% protein
(0.90*0.25) + (0.10*0.12)
(0.225) + (0.012) = 0.237
23.7% overall protein
Now, when using mostly Lab Blocks, the protein is up to 23.7%. This amount is closer to the protein in Lab Blocks (25%) than it is to the protein in Seed Mix (12%).
Notice that even those these mixes involve the same two foods, they have drastically different protein levels depending on the proportions mixed!
#3. Percentages must be calculated by weight, not volume or number of pieces. Hamster food is solid, and must be weighed in grams, ounces, or pounds. Not tablespoons or teaspoons or anything like that. 1 tablespoon of Oxbow Pellets and 1 tablespoon of seed mix is not a 50% / 50% mix of the two. Oxbow is lighter than most seed mixes, so 1 tablespoon of seed mix is actually more than 1 tablespoon of Oxbow.
CALCULATING – INTERACTIVE CALCULATORS
Now that you know the basics, it's time to actually calculate the GA.
So...I've tried to make this super-easy to do. I have created an interactive calculator that can be used to determine the GA of a mixed diet. All you need to do is enter the percentage of the diet and the GA of each food you use, and the calculator will determine the overall GA of your mixed diet.
I also created a calculator that can help you figure out how much (by weight) of each food you need to mix to get the diet you want. For example, if you want a diet that's 40% Hazel Hamster, 30% Oxbow, 20% Mazuri, and 10% Higgins Sunburst, this calculator will tell you how much of each food you need to add to get those proportions. The only thing is that you need to know the weight of 1 of the foods to start with.
CALCULATING THE WEIGHTS TO USE BASED ON PERCENTAGES YOU WANT
HAND CALCULATING
While the calculator is (I hope!) a useful tool, it can also be helpful to understand where the numbers come from.
METHOD 1 - PERCENTAGE CALCULATIONS
Spoiler
METHOD 2 - LARGE WEIGHT CALCULATIONS
Spoiler
FINDING GA FOR HUMAN FOODS
If you buy human-grade supplements (seeds, legumes, etc.), you'll noticed that they're labeled a lot different from pet food.
Pet food is labeled on a "percentage-by-weight" basis. For example, a bag of hamster food might be labeled 15% protein. What that means is that, by weight, that food is 15% protein and 85% other stuff. That other stuff includes fat, fiber, moisture, and so on. Pet food labels are based on the food's overall chemical composition.
Foods meant for humans are labeled very differently. They often not give percentage-by-weight numbers, but are instead labeled per serving size. They will have a Nutrition Facts label like the one for oats shown here:
The first thing you might notice is that there are a bunch of percentages (highlighted in red) on the right side. You need to ignore these - DO NOT USE THEM IN CALCULATIONS. These are not the percentages you are looking for, and if you use them, all of your analysis will be totally wrong.
They are the % Daily Values (%DV). They are based entirely on human dietary needs and have absolutely no usefulness for dealing with hamster nutrition. They are based around the idea that humans need a certain amount of each nutrient per day. Let's look at fat as an example. That label states that the 11g of fat in one 156g serving of oats provides 17% of the daily value for fat in humans. All it means is that if you eat a serving of oats, you're getting 17% of your fat for the day from those oats.
The point is, you have to make sure to ignore any %DV numbers (all highlighted in red) on the Nutrition Facts label.
Now, the good news is that we can figure out the percentage-by-weight for each nutrient with a little bit of math. To do this, the formula is:
[grams of nutrient] / [grams of total serving size]
The serving size is highlighted in yellow, and the grams of the nutrient (in this case, fat) is highlighted in green. Our serving size is 156g, and our grams of fat is 11g. So...
11g of fat / 156g serving size
11g / 156g = 0.0705
0.0705 = 7%
Oats are 7% fat by weight
Edited by Taxonomist, 28 January 2018 - 11:47 PM.
this is sure to help out lots of people!
Is the calculator down, or am I not understanding how to use it?
