305-Day Lactation Yield Estimator
Project a cow's 305-day lactation yield from her peak daily yield and persistency.
Total lactation yield is driven by peak yield and persistency (how slowly yield declines after the peak). Roughly: 305-day yield = peak × 30.5 × (1 − p^10)/(1 − p). A high peak with poor persistency loses to a modest peak that holds — so feeding and health after peak matter hugely.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.
Dairy and livestock farmers use the free 305-Day Lactation Yield Estimator for an accurate answer in seconds — no formulas to remember, works offline at the farm.
About 305-Day Lactation Yield Estimator
A cow's whole-lactation milk yield is set by two things: how high she peaks (around 6–8 weeks in) and how well she holds that yield afterwards — her persistency. This estimator projects the 305-day total from those two numbers, showing that a cow with a modest peak but flat decline can out-produce a flashy early peaker who drops away. It's a useful lens for judging young cows early and for valuing the post-peak feeding and health that protect persistency.
How to use 305-Day Lactation Yield Estimator
- 1Enter your animal/herd figures into the inputs.
- 2Read the headline result and the supporting breakdown.
- 3Apply the guidance in the note to your feeding decisions.
Why use 305-Day Lactation Yield Estimator?
- ✓Uses the standard, citable dairy-nutrition formula
- ✓Clear inputs with sensible defaults
- ✓Instant result with the working shown
- ✓Free, fully in-browser and private
Frequently asked questions
How do I estimate a cow's total lactation yield from peak?+
Use peak daily yield and monthly persistency: 305-day yield ≈ peak × 30.5 × (1 − p^10)/(1 − p). A 20-litre peak at 92% persistency projects to roughly 4,400 litres over the lactation.
What is persistency and why does it matter?+
Persistency is how well a cow maintains yield after her peak — the percentage retained each month. High persistency means a flatter, longer-lasting lactation curve, which usually produces more total milk and less metabolic stress than a high but quickly-declining peak.
Is this tool free and private?+
Yes — free, no sign-up, and all calculation runs in your browser, so it works offline at the farm and your data never leaves the device.
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