Calf Milk Replacers – The Ultimate Guide 

Calf milk replacers play a vital role in contemporary dairy farming, providing a well-balanced and carefully formulated nutritional alternative to support optimal calf growth and well-being. This guide delves into the essential components, advantages, and best practices for maximizing the effectiveness of milk replacers, supported by scientific research.

Why Use Calf Milk Replacers?

Milk replacers provide a cost-effective and biosecure alternative to whole milk, ensuring consistent nutrient delivery while reducing the risk of disease transmission. When formulated correctly, they can match or even exceed the growth rates of calves fed whole milk.

How to Choose the Best Milk Replacer for Your Farm

Selecting the right milk replacer is essential for ensuring optimal growth, health and early rumen development in calves. A high-quality milk replacer should mimic whole milk as closely as possible while being cost-effective and easy to digest. Here’s what to consider:

• Protein Source: Look for at least 20-24% crude protein, preferably from milk-based ingredients like skimmed milk, whey protein or casein. Avoid soy or plant-based proteins, as they are harder for young calves to digest 
• Fat Content: A good replacer contains 18-22% fat, derived from animal fats (butterfat, lard) or high-quality vegetable oils. This provides the necessary energy for growth 
• Osmolality & Digestibility: Opt for a milk replacer with an osmolality under 600 mOsm/kg to prevent scours and ensure easy digestion 
• Fortified with Vitamins & Minerals: Ensure it includes vitamins A, D, E, and B-complex, as well as essential minerals like calcium, phosphorus, selenium and zinc to support immune function and bone development 
• Mixing & Solubility: A good milk replacer dissolves easily in water at 40-45°C, without clumping

Key Ingredients in Calf Milk Replacers
– How to Analyse a Milk Replacer

When evaluating a milk replacer, focus on the nutritional composition and ingredient quality:

1. Protein Source
   ✅ Best Choices: Skimmed milk, whey protein, casein
   🚫 Avoid: Soy flour, plant-based proteins (harder to digest) 
2.  Fat Source
   ✅ Best Choices: Animal fats (butterfat), coconut oil, high-quality vegetable oils
   🚫 Avoid: Poor-quality vegetable oils, low-fat formulas 
3. Carbohydrates
   ✅ Best Choices: Lactose-based sources for energy
   🚫 Avoid: Excessive starches, sucrose (can cause digestive upset) 
4.  Essential Additives
   – Vitamins & Minerals: Ensure A, D, E, B vitamins, calcium, phosphorus, zinc
   – Prebiotics & Probiotics: Support gut health and immunity
   – Electrolytes: Help maintain hydration and prevent scours

A well-balanced milk replacer supports early calf development, reduces health issues and ensures efficient feed conversion for optimal farm performance. By choosing the right product and following a structured feeding plan, you can raise strong, healthy calves with excellent growth potential.

Feeding Strategies for Calf Milk Replacers

Once you’ve selected a quality milk replacer, proper feeding is crucial for calf health and performance. Here are the best practices, If you’re looking for answers like: how much milk replacer does a calf need per day, how long is calf milk replacer good for after mixing and how long should calves be on milk replacer.

1. Feeding Schedule

• Birth to Week 2: Feed 2-3 litres per meal, 2-3 times per day to support early growth
• Weeks 3-6: Increase total daily intake to 6-8 litres per day, depending on calf size and health
• Weeks 6-8: Gradually reduce milk intake while increasing access to starter feed and fresh water

But always remember to consult the protocols for each milk replacer to find out the best indication for use, as some may vary. 

2. Consistent Feeding Routine

• Maintain a strict feeding schedule to support digestion and reduce stress
• Use nipple feeders instead of buckets to encourage natural suckling, which enhances saliva production and digestion

3. Support Gut Health

• Ensure clean, fresh water is available at all times
• Introduce calf starter feed (18-22% protein) from week 1 to promote rumen development
• Use electrolytes during stressful periods (weaning, transport) to prevent dehydration. Tonisity Rum-Xm is a great option, as it is a highly-palatable isotonic protein solution, including a combination of bio-actives, that nourishes the calves’ intestinal cells

4 essential tips for the best use of calf milk replacers

1️⃣ Traditional Feeding

• 2-3 quarts, twice daily for 4-6 weeks
• Typically 20% CP, 20% fat formulation

2️⃣ Accelerated Feeding (Intensive Growth)

• Higher protein (28% CP) + Energy
• Designed for faster weight gain and earlier weaning

3️⃣ Winter Feeding

• Higher fat content (≥20%) or increased feeding volume to meet energy demands

4️⃣ Ad Libitum (Free Choice)

• Requires acidified milk replacers to prevent spoilage
• Ensures consistent energy and nutrient intake

Optimising Milk Replacers with Tonisity Rum-Xm 

Milk replacers are an excellent nutritional foundation for young ruminants, providing essential nutrients for early growth. However, they alone may not be enough to ensure maximum weight gain, optimal performance, overall health and strong body condition.

To bridge this gap, using bioactive compounds alongside milk replacers is highly recommended. These targeted nutrients support the complex digestive system of ruminants, ensuring better gut health, enhanced nutrient absorption and stronger immune function.

Tonisity Rum-Xm: The Key to Optimising Your Production

Tonisity Rum-Xm is a highly-palatable blend of key bioactives designed to nourish the gut of young ruminants from right after colostrum when added to milk or milk replacers.

By nourishing the gut through its rapid development in early life, Tonisity Rum-Xm supports better absorption of nutrients from milk or other feed sources, higher survival and can help with optimal lifetime performance. 

Scientifically Developed Formula

After years of research and testing, Tonisity Rum-Xm was formulated to provide targeted nutritional support:

• Composition: Whey protein, dextrose
• Additives: Flavouring compounds
• Analytical Constituents: 57% crude protein, 2.3% crude oils and fats, 17% crude ash, 1.7% crude fibre, 6.1% sodium
  

Why Use Tonisity Rum-Xm?

• Gut Health: The product can helps optimise the development of the intestine and microflora. It supports the immune system by promoting better absorption of nutrients, and supports in cases of gastrointestinal challenges 
• Administration: Tonisity Rum-Xm is easy to use, simply added to milk replacers and is recommended right after colostrum for at least 10 days, post colostrum. Calves require 3-4 litres per animal per day
• Improved Performance: Supplementing milk replacers with Tonisity Rum-Xm has been shown to promote weight gain, increase feed and water consumption and improve overall health and body condition, leading to improved lifetime performance of ruminants. (This data is based on testimonials from customers who have used it, trials are being carried out to scientifically verify the data) 

🚀 Want to Improve Calf Performance?

Using a high-quality milk replacer, paired with targeted gut health solutions like Tonisity Rum-Xm, are shown to help improve calf growth, health and lifetime performance. By focusing on protein quality, digestibility and consistency, farmers can optimise their calf-rearing programmes for better productivity and profitability.

Start integrating Tonisity Rum-Xm into your feeding programme today and watch your calves thrive!

Sign up for a trial on your farm by clicking here or send an email to our team sharing what you would like to improve, we’d love to hear from you!

info@tonisity.com