A new two-year study published in the Journal of Dairy Science looked at how different housing and feeding setups affect milk production, cow health, and profitability in dairy farms. The researchers compared three groups of cows:
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CB-TMR: Cows kept indoors in a compost barn and fed a full mixed diet (no grazing).
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CB-GRZ: Cows in a compost barn but also allowed to graze part of the time.
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OD-GRZ: Cows outdoors on shaded soil pens with some grazing.
The study covered cows that calved in both autumn and spring seasons.
Key Findings:
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Milk Production:
Cows fully confined indoors (CB-TMR) produced more milk and milk solids compared to cows in mixed systems (grazing plus supplement feeding). This gap was bigger for cows that calved in the spring. -
Housing Comfort:
Surprisingly, whether the cows in the mixed feeding groups were housed indoors (CB-GRZ) or outdoors (OD-GRZ) didn’t make a big difference to their overall production — although indoor housing (compost barns) did a better job protecting cows from heat stress during hot weeks. -
Feed Intake and Efficiency:
Confined cows ate more feed overall, used their feed more efficiently to make milk, and needed more concentrate (grain) per liter of milk compared to grazing cows. -
Cow Body Condition:
Cows in confinement kept better body reserves than cows in the mixed systems. -
Profitability:
Surprisingly, the outdoor grazing system (OD-GRZ) was the most profitable, even though it produced slightly less milk. Lower feed costs and simpler infrastructure made it a better financial choice. -
Seasonal Differences:
Regardless of the housing system, cows that calved in autumn performed better in outdoor setups compared to spring-calving cows, who struggled more with heat stress early in lactation.
Why It Matters:
As dairy farmers look for ways to balance milk production, cow welfare, and farm profits — especially in pasture-based systems common in places like Uruguay — these findings offer important insights. While keeping cows indoors boosts milk production, outdoor mixed systems can be more profitable overall. Plus, infrastructure choices like compost barns can help farms manage heat stress without fully giving up the benefits of pasture.
