Calcium: Phosphorus Ratios In Diet

Just adding a section on working out nutritional ratios - as this links in with the calcium topic ........

Chinchillas require calcium to phosphorous in the ratio of around 2:1 respectively (or at least 1:1) to ensure healthy skeletal and dental development (in conjunction with vitamins A, C and D) - as discussed!!

It is very likely that chinchillas can tolerate calcium ratios well in excess of the suggested 2:1, but more importantly, it is wise to ensure that the chinchilla is NOT eating a diet that has an inverted calcium:phosphorus ratio, as this (over time) may result in a decrease in bone density.

Most hays are naturally calcium to phosphorus balanced too. (This also includes Readigrass (Justgrass) and Supa Forage Excel, which are dried grass products)

Some examples:


Meadow Hay 0.29%/0.23%

Timothy Hay 0.43%/0.20%

Alfalfa hay (a lucerne not a grass) is high in calcium, and is a high energy food.

Alfalfa 1.24%/0.22%

Many of use also feed grains/cereals (oats/wheatgerm) in addition to pellets and hay - and I have borne this in mind…….

Cereals contain an inverted calcium to phosphorus ratio. Here are some average values.

Oats 0.05%/0.34%

Wheatbran/germ 0.13%/1.13%

Barley 0.05%/0.34%

It is worth bearing in mind that hays and grains are natural products and their mineral content may vary somewhat, depending on where and how they are grown, how and when they are harvested and how they are stored.


At the risk of boring you all, there is a way of calculating what ratio of calcium of phosphorus your chinchillas get in their diet…….

1. Weigh what you would feed one chinchilla in a day (these are examples only)……

Pellets 40g

Timothy Hay 40g

Oats 1.75g

Wheatgerm 1.75g

2. Multiply the weights by both the calcium and the phosphorus % content

Timothy Hay Calcium = 0.43 x 0.40 = 0.172g

Timothy Hay Phosphorus = 0.20 x 0.40 = 0.08g

Pellets Calcium = 1 x 0.40 = 0.4g

Pellets Phosphorus = 0.25 x 0.40 = 0.1g

Oats Calcium = 0.05 x 0.175 = 0.00875g

Oats Phosphorus = 0.34 x 0.175 = 0.0595g

Wheatgerm Calcium = 0.13 x 0.175 = 0.02275g

Wheatgerm Phosphorus = 1.13 x 0.175 = 0.19775g

3. Add all the calcium totals together = 0.6035g

Add all the phosphorus totals together = 0.43725g

4. Divide the total calcium by the total phosphorus.

0.6035 divided by 0.43725 = 1.45

So - this diet is 1.45:1 calcium to phosphorus

All of the above ratios are adequate and are not inverted.

Alfalfa given as an occasional treat will bump up the calcium levels slightly.

This is why a diet of pellets and hay is recommended - as it takes the guesswork out of balancing vitamin and mineral requirements!!

I hope that this is of interest.

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