Sheep · 7 min read
Sheep Breeding Calendar: Tupping Dates, Cycles and Lambing Dates
Updated 7 August 2026
Sheep are short-day breeders, so a sheep breeding calendar starts from the lambing month you want and counts backwards to a tupping date that still falls inside the autumn breeding season.
The two numbers that drive it: a 17-day oestrous cycle and a 147-day gestation.
When should you turn the ram in?
Subtract 147 days from the first day you want lambs. Most flocks in temperate climates tup between late September and early December for lambing from late February to early May.
Leave the ram in for two to three cycles — 34 to 51 days — so ewes that miss the first heat still lamb inside a manageable window.
| Ram in | Lambing starts | Notes |
|---|---|---|
| 1 September | 26 January | Needs early-breeding ewes or light treatment |
| 1 October | 25 February | Common early lambing flocks |
| 1 November | 28 March | Classic grass-based lambing |
| 1 December | 27 April | Late lambing, lowest housing cost |
Dates use a 147-day average; individual ewes lamb from about 142 to 152 days.
How often do ewes come into heat?
Because cycles are short, tupping groups synchronise naturally: expect a peak of lambings 17 days after the first peak, and a smaller third peak after that.
- Cycle: 17 days on average (14–19).
- Oestrus lasts 24 to 36 hours; ovulation is late in that window.
- Ram-to-ewe ratio: about 1 mature ram per 35 to 50 ewes, fewer for ram lambs.
- The 'ram effect' — introducing a ram after weeks of separation — tightens the first cycle.
How long are ewes pregnant?
Sheep gestation averages 147 days, with a normal range of 142 to 152 days. Hill and mountain breeds sit at the shorter end, and ewes carrying triplets often lamb a day or two early. Down breeds such as Suffolk tend towards 145 to 147 days; Merinos run closer to 150.
What is the lambing timeline after tupping?
| Days after tupping | Stage | Job |
|---|---|---|
| 0 | Tupping starts | Raddle the ram, record dates |
| 17 / 34 | Returns to heat | Watch raddle marks for repeats |
| 45–90 | Scanning window | Scan for pregnancy and litter size |
| 100 | Last third begins | Split into singles, twins and triplets |
| 120–130 | Rapid fetal growth | Increase concentrate; check body condition |
| ~133 (2–4 weeks out) | Pre-lambing | Clostridial vaccine, crutching, housing |
| 142–152 | Lambing | Lambing pens, iodine, colostrum ready |
When should you scan pregnant ewes?
Ultrasound between 45 and 90 days after the ram went in is the practical window: early enough to act on, late enough to count lambs accurately. Litter size is the single most useful number on a sheep breeding calendar because it sets feeding groups for the last six weeks.
- Before day 45 the count is unreliable.
- After day 90 counting gets harder as lambs overlap.
- Mark ewes by litter size at scanning, not later.
- Barren ewes found at scanning save eight weeks of feed.
What body condition should ewes be at each stage?
- Tupping: condition score 3.0 to 3.5 for lowland ewes, 2.5 for hill ewes.
- Mid-pregnancy: hold condition; losing more than half a score risks lamb loss.
- Pre-lambing: 3.0, with feeding stepped up in the final six weeks when 70% of lamb growth happens.
- Twin- and triplet-bearing ewes need separate, higher-energy feeding from about day 100.
Which calculator should you use next?
- Sheep due date calculatorAverage 147 days
- Goat due date calculatorAverage 150 days
- Cow due date calculatorAverage 283 days
- Alpaca due date calculatorAverage 345 days
More species are listed on the full gestation chart and in the guides index.
Common questions
Figures here are published reference ranges for planning, not veterinary advice. Confirm pregnancies and health decisions with your own vet.