MMN March 2025 – How Much is Enough When it Comes to Milk Replacer?

Your calf rearing policy should, from birth, ensure that you are giving heifer replacements the best opportunity to express their genetic potential as a productive animal when they enter the milking herd and that they remain productive over several lactations. Assuming all key colostrum protocols are being adhered to, the next key element of the calf rearing stage is milk replacer feeding. At a recent FAS event, there was a good discussion amongst the farmers present about feeding regimes for dairy calves, and there appears to be an increasing variance in the advice given on volumes and concentrations of calf milk replacer recommended for feeding to dairy calves.

The University of Nottingham have produced a handy online tool which allows different specifications, concentrations & volumes of milk replacer to be compared against target growth rates. It can be accessed through the AHDB website using the following link   Calf milk replacer energy calculator | AHDB

Using the calculator is a good way of assessing whether you are feeding your calves enough to meet your heifer rearing goals. Both examples below assume a twice a day feeding regime giving a total of six litres of milk with a milk replacer concentration of 150g/litre and an air temperature of 10^oC.

Example 1: 10-day old calf weighing 50kg.  Target 24-month calving, 650kg mature bodyweight and growing at 0.8kg/day

Example 2: 10-day old calf weighing 50kg.  Target 24-month calving, 700kg mature bodyweight and growing at 1kg/day

The examples demonstrate that in both scenarios, the current feeding regime is unlikely to achieve the targets set out and increasing the volume of milk being fed is justified. It is not uncommon now for calves to be fed eight litres per day on a twice a day feeding system and sometimes more on automated systems. Advice is also to build up milk volume quickly and that big strong calves can be consuming eight litres by seven days of age.

Key considerations when planning your milk replacer feeding regime:

• Age and weight of the calf; energy requirements increase with liveweight.
• Air temperature - energy requirement increases when environmental temperature is out with critical lower levels (below 15°C in calves under 60kg).
• Mature cow weight and calving age.
• Quantity and quality of starter feed intake once calves are over three weeks of age and eating meaningful amounts.

You can access funding through the Farm Advisory Service Specialist Advice Plan to assess all aspects of youngstock rearing on your farm to ensure your calves have the best chance of being healthy, productive cows in your herd.

https://www.fas.scot/specialist-advice/

alison.clark@sac.co.uk; 01776 702649