How Many Weeks Should a Calf Be on Milk Replacer?

Most calves remain on milk or calf milk replacer for 10 to 12weeks before being fully weaned. During this time, calves typically consume 6–8 litres per day, split into two feeds or delivered through an automatic feeder system.

The exact weaning age depends on calf health, concentrate intake and growth rate, but most calves are ready to transition off milk when they are consistently eating 1–1.5kg of calf starter per day.

Providing consistent calf nutrition during the first 8 weeks is critical for rumen development, immune strength and achieving strong daily live weight gain (DLWG).

 

Why Calves Stay on Milk for the First 10–12 Weeks

When calves are born, their digestive system functions very differently from adult cattle.

Milk bypasses the rumen and flows directly into the abomasum, the “true stomach,” where milk proteins and fats are digested efficiently.

During the first weeks of life, the rumen is still developing. As calves begin to eat calf starter feed, fermentation produces volatile fatty acids (VFAs) that stimulate the growth of rumen papillae, which allow the calf to digest solid feed effectively.

This is why milk feeding continues until calves are eating enough concentrate to support rumen development.

 

Standard Calf Feeding & Mixing Guide

The following guide outlines a typical feeding programme used on many dairy farms.

 

Calf Age	Total Litres Per Day	Feeding Frequency	Powder Concentration	Mixing Temp	Feeding Temp
0–24 Hours	3L (Colostrum)	Immediately after birth	First milking only	N/A	38°C
Days 2–7	4–6 litres	2 feeds	125g–150g per litre	42°C–45°C	38–39°C
Weeks 2–7	6–8 litres	2 feeds / automatic feeder	~150g per litre	42°C–45°C	38–39°C
Week 8+	Reduce by 50%	Once daily	150g per litre	42°C–45°C	38–39°C

 

Maintaining correct mixing temperatures and powder concentrations is essential when feeding calf milk replacer, as this ensures proper digestion and consistent nutrient intake.

 

Mixing Calf Milk Replacer Correctly

Correct preparation of calf milk replacer is essential to maintain calf health and avoid digestive upset.

Standard mixing guidelines include:

• Mixing temperature: 42°C–45°C
• Feeding temperature: 38°C–39°C
• Powder concentration: 125–150g per litre (12.5–15% solids)

Using a consistent mixing method helps ensure calves receive the correct level of energy and protein.

Some farmers also use a Brix refractometer to confirm milk solids concentration and ensure mixing accuracy.

 

When Should Calves Be Weaned?

Calves should not be weaned based solely on age. Instead, weaning should depend on concentrate intake and rumen development.

A calf is typically ready to wean when it:

• Eats1.5-2 kg of calf starter feed per day
• maintains a steady daily live weight gain
• is healthy with no digestive issues

Most calves reach this stage between 10 and 12 weeks of age.

Gradually reducing milk intake helps prevent stress and encourages higher concentrate consumption.

 

Gradual Weaning vs Abrupt Weaning

A gradual reduction in milk is usually recommended.

A typical approach includes:

Week 8
Reduce milk allowance by 30–50%

Week 9
Move to once-a-day feeding

Week 10-12
Fully wean once concentrate intake remains consistent

This method supports rumen development and helps maintain growth rates after weaning.

 

Whole Milk vs Calf Milk Replacer

Many farms choose calf milk replacer because it provides:

• consistent nutrition
• reliable mixing performance
• easy storage and handling
• predictable feeding results

High-quality calf milk replacer in Ireland ensures calves receive the correct balance of protein, fat and micronutrients required for early growth.

Working with trusted calf milk replacer stockists also ensures consistent supply during the calving season.

 

Supporting Calf Growth and Performance

Successful calf rearing depends on consistency in feeding, hygiene and monitoring.

Providing the correct feeding programme during the first 10–12 weeks supports:

• stronger rumen development
• improved feed conversion
• higher lifetime milk potential
• optimal daily live weight gain

Combined with good housing, clean water and high-quality starter feed, this approach ensures calves transition smoothly from milk to solid feed.

 

Helping Calves Transition Successfully

Most calves remain on milk replacer for 10 to 12 weeks, but successful weaning depends on more than just age. Monitoring concentrate intake, supporting rumen development and gradually reducing milk intake are key steps in ensuring calves continue to grow strongly after weaning.

Using a high-quality milk replacer and following a consistent feeding programme helps calves achieve strong daily live weight gain while developing a healthy digestive system.

Eringold calf milk replacers are designed to support optimal calf nutrition, reliable mixing and excellent early growth performance.

For advice on calf milk replacer feeding programmes, automatic feeders or locating trusted Eringold calf milk replacer stockists in Ireland, get in touch with the Eringold team today.

 

Frequently Asked Questions About Calf Milk Replacer

How long should calves stay on milk replacer?

Most calves remain on milk or calf milk replacer for 10 to 12 weeks. However, calves should only be weaned once they are eating at least 1.5–2kg of calf starter per day, which indicates the rumen is developing properly.

 

Can calves be weaned earlier than 10 weeks?

Early weaning is possible in some systems, but it requires calves to consume enough concentrate feed to support rumen development. Weaning too early can reduce growth rates and lead to setbacks in daily live weight gain (DLWG).

 

How much milk replacer should calves receive before weaning?

Most calves receive 4–6 litres per day in the first weeks, increasing to 6–8 litres per day before weaning. Milk replacer should typically be mixed at 125–150g of powder per litre of water.

 

What is the best temperature to feed calf milk replacer?

Milk replacer should be mixed at 42–45°C and fed to calves at approximately 38–39°C, which is close to body temperature. Feeding milk that is too cold can reduce digestion efficiency.

 

How do you know when a calf is ready to be weaned?

A calf is generally ready for weaning when it:

• eats 1.5-2 kg of calf starter per day
• maintains steady growth
• shows no digestive problems
• drinks less milk naturally

At this stage, gradually reducing milk intake encourages calves to rely more on solid feed.