Sheep grazing a wide green paddock in Southland, with hills and mountains behind
Handy tools

Lambing percentage calculator

Follow a mob of ewes from scanning to tailing to weaning: your lambing %, how many reme (lambs) were lost along the way, and what a few more lambs alive at tailing would be worth.

Southland (Murihiku) · Photo: Pedro Szekely, CC BY-SA 2.0

1. The mob

2. Scanning results: ewes carrying (optional)

Ewes not counted here are taken as empty (dry). Leave all three empty if the mob wasn't scanned.

3. Lamb counts

4. What is a lamb worth? (optional)

Use your own lamb price - for example the sale value calculator turns a c/kg schedule into dollars a head.

Showing an example mob (TEST numbers, not a real farm) - replace it with your own.

Your lambing results

Lambing % (lambs tailed per 100 ewes to the ram)136.7%1.37 lambs tailed per ewe · 5.6 points above the national 131.1% for spring 2025
Scanning %145.3%2,180 lambs scanned · 140 ewes empty (9.3%)
Lambs alive at tailing, of those scanned94.0%130 lambs lost between scanning and tailing
Weaning %130.0%100 lambs lost from tailing to weaning (4.9%)

If 5 more of every 100 lambs scanned made it to tailing: about 109 more lambs - worth about $15,260 at $140 a lamb, and a lambing % of 143.9%.

  • Scanned145.3%

    2,180 lambs · 1.45 per ewe

  • Tailed136.7%

    2,050 lambs · 1.37 per ewe

  • Weaned130.0%

    1,950 lambs · 1.30 per ewe

Lamb income at $140 a lamb: about $182 per ewe put to the ram (lambs weaned).

Link to these numbers

How it is worked out

  • Lambing % = lambs tailed (docked or marked) ÷ ewes put to the ram × 100 - the way most New Zealand farmers and vets count it. 1,500 ewes and 2,200 lambs tailed is 147%.
  • Scanning % = lambs scanned (singles + 2 × twins + 3 × triplets) ÷ ewes put to the ram × 100. Survival = lambs tailed ÷ lambs scanned - the gap is the lambs lost around birth.
  • National picture: 131.1% for spring 2025 (Beef + Lamb New Zealand, Lamb Crop 2025 (10/12/2025)). It is an average of all farms - hill country, hoggets and breeds differ, so compare your own mob year on year first.

This is a record-keeping tool, not veterinary advice. Most lamb losses happen in the first few days of life - ewe body condition, shelter, feed in late pregnancy and lambing-paddock set-up all play a part. Talk to your vet or farm advisor about your own losses; Beef + Lamb New Zealand has free guides on ewe and lamb survival. Nothing you type is stored or sent anywhere. Planning ahead? Work out lambing dates with the due date calculator and feed with the stock units calculator.

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