Calf milk replacer mixing rates

Every calving season farmers ask what calf milk replacer concentration is best for their calves. There are many different guidelines and label recommendations available, and this can often create confusion.

To help, here are guidelines to assist in making the best decisions for your system, though rearing calves is a complex process and this is not a complete guide.

First, determine the requirements of the calf in grams (g) of milk powder. This is a better way to calculate calf requirements than total litres (L). To support good calf growth and health, it is recommended to feed 1.5 to 2 percent of liveweight in milk solids each day. For a 40 kg calf, this would be 600 to 800 g per day.

Secondly, confirm the total volume being fed per day to calculate the mixing rate of the calf milk replacer (CMR) per L to attain the total grams of CMR for each calf. For example, if feeding 600 g of CMR and feeding 4 L a day, over two feeds, the mixing rate would be 150 g of CMR per L. If mixing the CMR at 125 g per L, each calf would need to drink 4.8 L to achieve the same milk solids intake.

Correct mixing procedure to make 2 L of CMR at 150 g per L, is to add 1 L of warm water to the bucket, and then 300 g of CMR. Mix until dissolved, then add more water to reach a total volume of 2 L.

High concentration mixing rates of CMR can cause a nutritional upset. As a general rule, do not exceed 180 g of CMR per L without further advice from a nutritionist or veterinarian.

When mixing higher concentrations of CMR the following management practices are important to mitigate the risks of animal health issues, such as nutritional scours, bloat, and poor performance.

• Seek advice if making changes to mixing rates for the first time.
• Fresh water must be always supplied to calves. Whole milk or CMR feeding does not meet the fluid requirements of the calf. Access to water reduces the risk of bloat from milk feeding, especially when higher mixing rates are used.
• Have control over individual animal intakes by using compartment feeders or controlled automatic feeders.
• Have mobs of calves of equal size to ensure equal competition.
• Make any changes gradually over three to four days.
• It is important to do one change at a time when rearing calves. For example, do not switch to once-a-day feeding and change the CMR concentration on the same day.

For more information on calf rearing, contact your local PGG Wrightson Technical Field Representative.