Lambing Season in Australia – What Farmers Need to Know

Lambing season is simultaneously the most exciting and most demanding time of the sheep farming year. The birth of new lambs represents the year's productivity potential — and the decisions you make in the weeks before, during, and after lambing will determine how much of that potential you actually capture.

Australia's sheep industry loses an estimated 15–20% of lambs born each year before weaning. Much of this loss is preventable. With the right preparation, attentive management, and a clear understanding of what can go wrong, good farmers consistently achieve marking rates of 100–130%+ while others in the same district struggle to reach 75%.

This guide covers everything Australian sheep farmers need to know about lambing season — from joining planning through to marking, and all the critical management points in between.

Understanding the Lambing Calendar

Australia's diversity of climates means there is no single "lambing season." When you lamb depends on your production system, your climate, your breed, and your target market.

Joining and Pregnancy Timeline

Sheep have a gestation period of approximately 147 days (21 weeks). Most breeds (Merino, Border Leicester, Poll Dorset, Corriedale) are seasonally polyoestrous — they cycle as day length shortens from late summer through autumn and winter, with the breeding season typically running from late January to July in southern Australia.

Working backwards:

Common Lambing Times by Region and System

Southern Australia (Victoria, SA, southern NSW, SW WA): - Traditional Merino: July–September (winter/spring) - Prime lamb (Poll Dorset, first-cross): August–October - Some producers aim for autumn lambing (May–June) to produce heavier lambs for the Christmas market

Northern and arid Australia (Queensland, northern NSW, WA north): - Dorper and shedding breeds: more flexible; lambing can coincide with green feed after summer rains (February–April) - Traditional Merino pastoral: June–August

Tasmania and high-altitude southern Victoria: - Later spring lambing (September–November) to avoid the coldest periods

Out-of-season lambing is possible with Poll Dorsets, Dorpers, and some Merino bloodlines. Specialist out-of-season systems using hormonal treatments (CIDR, melatonin implants) can produce lambs in any month, allowing farmers to target premium Christmas or Easter markets.

Preparation Before Lambing

Good lambing outcomes are built in the months before a single lamb hits the ground.

Ewe Condition Score at Joining

Body condition score (BCS) is a hands-on assessment of fat and muscle cover on a 1–5 scale (1 = emaciated, 5 = obese). Ewes should be joined at:

• BCS 3.0–3.5 for optimal conception rates and twin production
• Ewes below BCS 2.5 at joining have reduced ovulation rates (fewer twins) and are more likely to die during pregnancy and lactation
• Ewes above BCS 4 can have dystocia (difficult births) and metabolic issues

The key point: condition at joining determines how many lambs you'll have. You cannot fix poor condition score quickly. Start assessing ewes 8–12 weeks before joining and supplement if needed.

Flushing

Flushing is the practice of improving ewe nutrition for 3–6 weeks before and during joining to increase ovulation rate and conception. Moving ewes to fresh, high-quality pasture or supplementing with 200–300g grain/day during this period can lift twinning rates by 10–20% in ewes that were in moderate condition.

Flushing works best in ewes at BCS 2.5–3.0. It has less effect on ewes already in good condition, and doesn't compensate for very poor condition (BCS < 2.0).

Ram Preparation

Don't forget the rams. Check them 6–8 weeks before joining: - Examine feet (no lameness or footrot) - Check body condition (join at BCS 3.5–4.0) - Inspect testicles (firm, symmetrical, no lesions) - Assess libido if possible - Vaccinate with 5-in-1 or Glanvac if not recently done - Run a serving capacity test for high-value rams

Ram:ewe joining ratios: - Uncontrolled joining: 1:40–60 ewes - Controlled joining (synchronised): 1:10–20 - Vasectomised teaser rams: 1:80–100 ewes, used to "tease" ewes before joining

Pregnancy Scanning

Ultrasound pregnancy scanning at 70–90 days of pregnancy (mid-pregnancy) is one of the highest-return investments in lambing management. Scanning: - Identifies dry (empty) ewes for early culling or separate management - Separates singles from multiples - Allows differential feeding of twin-bearing ewes (they need more)

The cost is $0.50–$1.50 per ewe — an extraordinary return when it allows you to target supplementary feed to the ewes that need it most and removes the burden of feeding confirmed dry ewes.

Feeding in Late Pregnancy

The critical feeding period is the last 6–8 weeks of pregnancy, when 70% of foetal growth occurs. Nutritional requirements increase dramatically:

• Single-bearing ewe: 1.5–1.8 DSE in late pregnancy
• Twin-bearing ewe: 1.8–2.2 DSE in late pregnancy
• Triplet-bearing ewe: 2.5+ DSE

Feed energy shortfalls in late pregnancy cause: - Pregnancy toxaemia (twin lamb disease) — a life-threatening metabolic disorder in underfed ewes carrying multiple lambs - Low birth-weight lambs with reduced survival - Poor colostrum production - Poor milk let-down and ewe-lamb bonding

If pasture is inadequate, supplement with hay and/or grain. Lupins, barley, or a commercial sheep pellet are all suitable. In the last 3–4 weeks, 200–400g grain/day per ewe (adjusted for body size and litter size) is a common recommendation.

Trace Element Status

Selenium and iodine deficiencies can cause "white muscle disease" in lambs (selenium) and goitre and lamb mortality (iodine). Both are common in parts of Australia, particularly in high-rainfall areas on granitic or sandy soils.

Test your ewes' trace element status (via blood test) 6–8 weeks before lambing. If deficient: - Selenium: inject ewes with Selenate (sodium selenate) 4–6 weeks before lambing; alternatively use selenium-fortified pellets or licks - Iodine: inject ewes with iodised oil 4–6 weeks before lambing (Iodovite or similar)

Trace element deficiency is an underappreciated cause of lamb deaths. Getting this right costs very little and can dramatically improve lamb survival.

Vaccination

All ewes should receive a 5-in-1 vaccine booster (covering pulpy kidney, tetanus, black disease, blackleg, and malignant oedema) 4–6 weeks before lambing. This boosts antibody levels in colostrum, providing passive immunity to newborn lambs.

Some farmers also vaccinate with Glanvac 6B (adds a Johne's disease component) or Gudair (for OJD control in at-risk flocks).

Do not vaccinate within 4 weeks of the expected lambing date — the stress of handling late-pregnant ewes can trigger early labour.

Lambing Paddock Selection

Choosing the right paddock for lambing is more important than many beginners realise.

Good lambing paddock characteristics: - Well-sheltered from prevailing winds and rain (trees, hills, windbreaks) - Good feed quality and quantity — ewes need to eat soon after lambing - Accessible for daily observation without excessive disturbance - Not prone to waterlogging (cold, wet conditions are the #1 killer of newborn lambs) - Away from areas with high fox or dog activity

Avoid: - Bare paddocks with no shelter - Very large paddocks where ewes can wander far and lose contact with lambs - Crops or dense tall pasture where lambs can get lost - Paddocks with dams where lambs can drown

Lambing density: For intensive systems, confine ewes in smaller paddocks during the peak lambing period. A smaller area means you can find and check more lambs. For extensive pastoral systems, this isn't always practical, but maximising shelter available is still important.

The Critical First 24 Hours

Lamb survival is largely determined in the first 24 hours of life. The three main killers of newborn lambs are:

1. Starvation/mismothering/exposure (SME) — accounts for 50–70% of all lamb deaths 2. Dystocia (difficult birth) — accounts for 10–20% 3. Predation (foxes, wild dogs) — accounts for 10–30% in unprotected flocks

Colostrum is Everything

A lamb must receive adequate colostrum within 6 hours of birth. Colostrum is the first milk — rich in antibodies, energy, and growth factors. A lamb that doesn't receive colostrum is immunologically naked and will almost certainly die.

The minimum effective dose is 50 ml/kg body weight within 6 hours, and 200 ml/kg in the first 24 hours.

Signs a lamb hasn't received adequate colostrum: - Hunched, cold, shivering - Not seeking the teat - Vocalising weakly - Eyes sunken or dull

Intervention: Milk the ewe and tube-feed the lamb if it won't suck. Colostrum from another freshly lambed ewe or frozen colostrum reserve (cow or ewe colostrum frozen at the start of the season) are ideal. Commercial colostrum replacers are available but are second-best to fresh colostrum.

Lamb Hypothermia

Cold, wet, windy conditions are lethal to newborn lambs, particularly those born small (twins and triplets). A lamb's core temperature can drop below 37°C within an hour in bad weather.

Hypothermia treatment: - Rectal temperature > 37°C: warm, dry, stomach tube with colostrum - Rectal temperature 32–37°C: warm with heat lamp or in a warming box, then tube with colostrum - Rectal temperature < 32°C: warm first (do NOT tube-feed — aspiration risk at this temperature). Rub dry, place in warming box, check temperature every 30 minutes. Only tube once above 32°C.

Every lambing shed should have a heat lamp, a stomach tube and syringe, and frozen colostrum reserves at minimum.

Mismothering

Ewes occasionally abandon or reject lambs, particularly: - Twin and triplet lambs (the ewe bonds best with the first lamb born while still delivering the second) - Ewes that were disturbed during labour - First-time mothers (maidens)

Prevention: - Confine ewes with their lambs in small "mothering-up" pens (2–3 m²) for 12–24 hours after difficult births - Minimise disturbance during peak lambing - Keep a close eye on maiden ewes

Graft lambing: If a ewe dies or has triplets she can't support, lambs can be grafted onto another ewe. Techniques include using the dead lamb's skin over the orphan, or chemical grafting sprays that mask the lamb's scent.

Daily Lambing Checks

During peak lambing, farms should be checked at least twice daily — ideally at dawn and again in the afternoon. Look for:

• Ewes in labour (is progress being made? If a ewe has been straining for more than 2 hours without a lamb appearing, intervention is needed)
• Newborn lambs that appear cold, weak, or separated from their mother
• Lambs not suckling
• Ewes with no lamb (or a lamb they're not claiming)
• Dead lambs (record and investigate causes)

A good lambing check record — how many lambs born, how many born dead, how many assisted, how many treated — is invaluable for year-on-year improvement.

Dystocia (Difficult Births)

Dystocia occurs when a lamb cannot be delivered normally. Common causes: - Lamb malpresentation (head back, leg back, breech) - Oversized single lamb - Narrow ewe pelvis (first-time mothers) - Multiple lambs simultaneous presentation

Signs: ewe straining without progress for 30–60 minutes; visible lamb parts but no further progress.

Intervention: Wash hands thoroughly, lubricate, and gently assess presentation. Correct malpresentation by pushing the lamb back and repositioning. Use firm, steady traction during contractions. If in doubt — call your vet. Unnecessary rough intervention causes more damage than waiting for professional help.

Marking

Lamb marking (also called "processing" or "tailing") is typically carried out at 2–6 weeks of age when lambs are strong enough to handle the procedure but not so old that recovery is more difficult.

Procedures at marking typically include:

• Tail docking: Reduces flystrike risk. Use rubber rings (under 7 days), hot iron, or knife. Leave enough tail to cover the vulva in ewes.
• Castration of male lambs not intended for breeding: rubber rings (under 7 days), Burdizzo clamp, or surgical
• Ear tagging: NLIS (National Livestock Identification System) tags are legally required for sheep to be moved off-property
• Ear marking or tattooing: For flock identification
• Vaccination: First 5-in-1 shot at marking; second dose at weaning (4–6 weeks later)
• Weighing: Record birth weight and marking weight for performance monitoring

Use pain relief where possible. Products like Tri-Solfen (topical anaesthetic/antiseptic) for ring application and Metacam (meloxicam) for post-procedure pain are increasingly standard practice and improve animal welfare outcomes.

Lamb Losses: Recording and Learning

Don't just note dead lambs — investigate them. Examining dead lambs reveals: - Cause of death (exposure, starvation, pneumonia, dystocia, predation) - Whether ewes had enough milk (check abomasum contents — milk present = lamb fed; empty = starvation) - Whether colostrum was received (check gut contents within 24 hours of birth)

Patterns in lamb deaths allow targeted management changes. If most deaths are starvation in twin lambs — improve ewe nutrition. If they're predation — reinforce fencing or use guardian animals. If they're exposure in wet weather — provide better shelter.

Weaning

Lambs are typically weaned at 10–14 weeks of age (or earlier if ewes are losing condition badly). At weaning: - Separate ewes and lambs by at least 2 km (or two paddocks from each other) to reduce vocalisation and attempted reunion - Booster vaccination (second 5-in-1) - Assess lamb weights and identify any that need a "booster" (draft off light lambs and give them preferential feeding) - Draft rams from ewes - Begin your post-weaning parasite management program

Summary: Key Dates and Actions

Lambing season will test your observation skills, your stamina, and your stockmanship. But it is also where the real rewards of sheep farming are found. A paddock full of healthy, strong lambs bouncing in the morning sun is one of farming's great pleasures — and it doesn't happen by accident.