Fortified milk for calves: why and how

Fortified milk is the result of adding calf milk replacer to whole milk.

Fortifying whole milk increases the plane of nutrition during the milk feeding phase – providing a high energy, high protein feed in the volume of milk you would normally feed.

Why fortify whole milk?

Whole milk can vary significantly in solids content.
Lower solids mean lower energy intake for calves.
Fortifying milk increases total solids and energy intake.
A higher plane of nutrition helps drive higher average daily gains.
There’s clear evidence that preweaning growth rates in heifers is key to optimal mammary tissue development and subsequent lifetime milk production.

Body weight and ADG from fortified milk

The graph shows that calves fed fortified milk achieved an average daily gain of 617g per day, compared with 514g per day from milk only.

By day 56, calves fed fortified milk reached approximately 61kg body weight, compared with 57kg for calves fed milk only.

What does milk fortification mean in practice?

Many dairy heifer rearers in New Zealand have access to transition milk and this is a valuable source of nutrients for young calves.

Feeding calves ad lib on whole milk is one way to support good early nutrient intakes which increases growth rates and lifetime productivity.

Where you have limited milk supply, fortifying the milk will increase the concentration of solids in the milk from the typical 12.5% up to as much as 20%.

Note:

Fortification is not the same as increasing the volume of milk offered by mixing reconstituted milk replacer with milk.
In most cases, fortifying milk will increase the osmolality of the milk.
It is imperative to ensure calves on fortified milk have ad lib access to clean water ALWAYS.

How to fortify whole milk

There are several different options for whole milk fortification. Choose a method which is going to work well in your system and with the specific milk replacer you are using.

Option 1: add milk replacer directly to milk.

This option works well with Sprayfo calf milk replacers because our products are designed to mix very easily.

For example:

Add 125 g of milk replacer to 4L of milk (or 6.25 kg of milk replacer to 200 L of milk): this will be the same as feeding just over 1L more milk to your calves but without the extra volume.
Add 250 g of milk replacer to 4L of milk (or 12.5 kg of milk replacer to 200L of milk): this will be the same as feeding an additional 2L of milk but without the extra volume.

If you are using cold milk, make sure that you mix the blend well to prevent any lumps which may block teats.

Option 2: mix the powder required with a small volume of hot water before adding it to milk.

This can be useful to help ensure that there are no lumps in the final solution and, depending on the volume being fed, it may have a benefit in that it does help to slightly increase the temperature of the solution being fed.

If you choose to use this method:

Make 125 g of milk replacer up to 500mL (or 12.5kg of milk replacer up to 50L) with warm (50–60°C) water and add this to 1.5L (or 150L of milk), to give you 2L (or 200L) of milk with approximately 15.5% solids.
Feeding 4L of this solution will be equivalent to feeding 5L of milk.

If you wanted to mix a solution which would provide the same amount of nutrition in 4L as feeding 6L:

Make 220 g of milk replacer up to 750 mL (or 22 kg of milk replacer up to 75 L) with warm (50–60°C) water and add this to 1.25 L (or 125 L of milk), to give you 2 L (or 200 L) of milk with approximately 19% solids.

Important to note when feeding fortified milk to calves:

Maintain consistency in both feeding temperature and mixing rates.
Take the time to measure out the volumes of milk and water you are using and make sure you use the same amount of powder and milk, or milk and water every time.
Ensure that calves have ad lib access to clean fresh water ALWAYS. This is imperative.
Fortified milk can have a higher osmolality.