The Power of Separate Grouping: Simplifying Dairy Herd Management

Victoria Asselstine, Ph.D., Ruminant Technical Service Manager 
Sarah Dean, M.Sc ., Ruminant Technical Specialist

Managing a dairy herd is all about balance — balancing performance, cow comfort, and simplicity. In modern dairy herd management, one of the most effective ways to reduce cow stress and improve long-term milk performance is through separate grouping of first-lactation heifers and mature cows. This simple management practice supports steadier feed intake, better transition health, and smoother daily routines.

Take-home messages

• Separate grouping reduces social stress and improves feed intake consistency.
• Heifers and mature cows thrive when fed according to their nutritional needs.
• Precision feeding leads to better transition performance and long-term productivity.
• Less regrouping = calmer cows, better routines, and improved milk yield.

Why grouping matters

Cows are social animals that naturally form hierarchies. Mature cows dominate feeding and resting areas, while timid heifers often get pushed aside. When heifers share pens with older cows, they spend more time standing and less time eating or resting — clear signs of social stress.

That stress can have real consequences. Reduced feed intake before calving leads to greater drops in dry matter intake (DMI) and a higher risk of metabolic issues after calving. It can also lower rumination time and interfere with rest, two key behaviors for rumen health and immune function.

By keeping first-lactation cows together, producers can reduce social competition and help maintain steadier feed intakes — supporting better health, more consistent performance, and a smoother transition into lactation.

Less regrouping, less stress

Every time cows are regrouped, their social order is disrupted. Studies show that regrouping can reduce feeding rate by around 10%, lower rumination by 9%, and cause cows to spend less time lying down. Milk yield often drops temporarily as cows re-establish their hierarchy.

Minimizing regrouping — and separating young cows from mature ones early — helps maintain social stability and keeps production consistent. In practical terms, it also means fewer disruptions at the feed bunk, calmer cows, and more predictable herd behavior.

Better nutrition, better results

Separate grouping also opens the door to precision feeding. Heifers have different nutrient requirements than older cows. By feeding each group according to its specific needs, producers can improve feed efficiency, reduce waste, and get more value out of every kilogram of feed.

Even if facilities can’t easily be modified, paying attention to how first-lactation animals are managed before and after calving can make a big difference. Nutritional support — such as adding B vitamins — helps cows handle the stress of entering the milking herd and maintain energy balance during this demanding time.

For more information on transition cow nutrition, explore Jefo’s dedicated resources.

Small changes, lasting benefits

Producers who keep their first-calf heifers separate often notice calmer animals, steadier feed intakes, and fewer post-calving health issues like mastitis or ketosis. Over time, these small improvements add up — less stress, better health, and more consistent milk production.

Every herd is different, but the principle remains the same: reducing social stress helps cows perform at their best.

Talk with your Jefo nutrition advisor to discuss grouping and feeding strategies that fit your farm setup and help your herd thrive.