Lambing in Australia

Lamb mortality is the single largest source of production loss in Australian sheep enterprises. National estimates consistently put pre-weaning lamb mortality at 15 to 25% across the industry — in poor years or poorly managed properties, it can exceed 40%. The majority of these deaths are preventable. Understanding what kills lambs is the starting point for reducing mortality, because the interventions required differ substantially depending on the cause.

Approximately 60 to 70% of lamb deaths occur in the first 48 hours of life, and within that window, the overwhelming causes are: starvation-mismothering-exposure (SME) complex, which accounts for roughly 50% of all pre-weaning mortality; and dystocia (difficult birth), which accounts for a further 10 to 15%. The remaining deaths are spread across a long tail of causes including congenital defects, trauma, and disease — important individually but smaller in aggregate than the SME complex.

The SME complex is a syndrome, not a single cause. A lamb dies from this complex when it fails to receive adequate colostrum in the first hours of life — either because it was separated from its dam (mismothering), because it was too weak from a difficult birth to nurse effectively (dystocia-related), or because the ewe rejected it or was unable to produce adequate milk (starvation-related). The common thread is that the lamb does not get what it needs from its mother in the first 24 hours, loses heat faster than it can generate it, and dies from hypothermia and hypoglycaemia in combination. Understanding this mechanism clarifies why all the lambing management interventions that matter — body condition of ewes, lambing paddock quality, weather protection, ewe:lamb bonding time, colostrum supplementation — are aimed at either ensuring the ewe and lamb get off to the best possible start, or compensating quickly when they do not.

Lamb survival is significantly influenced by genetic factors as well as management. Ewe mothering ability (the propensity of a ewe to stay with her lambs, vigorously clean them, and encourage nursing) varies widely and is moderately heritable. Lamb vigour (the speed with which a lamb stands and seeks the teat after birth) also varies and has a genetic component. Selection for these traits through estimated breeding values (EBVs) where they are available, and culling of ewes with documented poor mothering history, gradually shifts the distribution of the flock toward better outcomes. The genetic contribution operates slowly over multiple generations, while management improvements act immediately — both are worth pursuing simultaneously.

The six weeks before the first lamb is born are the most important management period of the entire year for a breeding ewe flock. The decisions made during this period — about nutrition, vaccination, ewe health, and infrastructure — set the ceiling for what the lambing season can achieve. Rushing into lambing season without adequate preparation and trying to compensate reactively is the defining characteristic of high-mortality enterprises.

Body condition scoring at six weeks pre-lambing is the first essential task. Ewes should be at BCS 3 to 3.5 entering the final six weeks of pregnancy. Ewes below BCS 2.5 are at high risk of pregnancy toxaemia and are likely to produce smaller, weaker lambs and have lower colostrum production. Ewes above BCS 4 are at increased risk of difficult births (large lambs from well-nourished ewes, combined with reduced pelvic mobility from fat deposition) and of hepatic lipidosis if they develop pregnancy toxaemia.

Draft ewes carrying multiples — identified by pregnancy scanning at 60 to 70 days gestation — into a separate mob for preferential feeding during the final weeks. Multiple-bearing ewes have substantially higher nutritional requirements than singles and will lose ground rapidly if mixed with singles and fed a uniform ration. Supplement with 300 to 500 grams of grain per head per day for twin-bearing ewes, increasing to 500 to 700 grams for triplets, with quality lucerne or oaten hay available ad libitum. The scanning and drafting cost is negligible against the improvement in survival rates and reduced pregnancy toxaemia losses.

Vaccination of all ewes with a booster dose of 6-in-1 (or 5-in-1) clostridial vaccine four to six weeks pre-lambing is essential. This boosts the antibody concentration in colostrum at peak levels, providing passive immunity to lambs for the critical first six to twelve weeks of life. A ewe vaccinated only at the beginning of the season — without a pre-lambing booster — will provide some passive immunity, but the booster dose significantly increases colostrum immunoglobulin concentration. If ewes have not been vaccinated during the current pregnancy and time does not allow the full pre-lambing protocol, vaccinate as soon as practically possible — some protection is better than none.

Selenium and vitamin E supplementation in selenium-deficient areas should be administered to ewes four to six weeks pre-lambing if not already covered by a slow-release bolus program. Selenium-deficient ewes produce lambs with white muscle disease (nutritional muscular dystrophy) — lambs that are weak, unable to stand properly, and unable to nurse normally. The condition is a significant cause of lamb losses in high-rainfall areas of southeastern Australia and is entirely preventable. Injectable sodium selenate at the recommended dose for ewes pre-lambing is the most reliable supplementation route.

Lambing paddock preparation is a practical task that is often deferred until too late. The lambing paddock should be: rested from sheep grazing for at least four to six weeks before lambing begins (to reduce pathogen load and allow pasture regeneration); sheltered from prevailing cold winds, with natural windbreaks from vegetation, land form, or structures; grazed to a manageable sward height (15 to 20cm is ideal — long grass hides lambs, very short grass reduces feed for ewes and provides insufficient insulation for recumbent lambs on cold nights); and stocked at the density appropriate for your monitoring capacity (the fewer ewes per hectare, the more intensive your monitoring can be per ewe). In cold climates, paddocks on north-facing slopes (in the southern hemisphere, these catch maximum winter sun) have consistently better lamb survival outcomes than south-facing or exposed paddocks.

Equipment and supplies should be assembled and accessible before lambing starts. The essential kit: a lambing pack with iodine (10% solution for navel dipping), colostrum replacer (frozen colostrum from earlier lambings, or commercial replacer — have adequate supply on hand), stomach tube and syringe for weak lambs, lambing lubricant, disposable gloves, antiseptic spray, marking equipment, a small heat lamp and extension cord for reviving hypothermic lambs, a digital thermometer, ear tags, and records. Keep the kit in the ute or shed, not stored in a shed far from the lambing paddock.

Understanding what normal ovine labour looks like is essential before you can recognise what abnormal labour looks like and make appropriate decisions about when to intervene. Unnecessary intervention in normal labour causes injury, stress, and infection; delayed intervention in obstructed labour causes death. The judgement call is one of the most important skills in lambing management.

Ewes approaching lambing show a predictable behavioural progression over the hours before delivery. In the final 12 to 24 hours, the ewe becomes restless, paws the ground repeatedly, and separates from the mob. She may lie down and get up repeatedly. Udder development has been increasing over the preceding weeks and by the time of delivery the udder is tight and full. The vulva becomes swollen and moist. These are all normal signs of imminent delivery and do not require intervention.

Active labour begins when the cervix dilates and uterine contractions become coordinated and visible. In this first stage, the ewe will strain intermittently and the water bag (allantoic sac) will typically appear at the vulva and then rupture. From the appearance of the water bag to the appearance of the lamb's feet should be no more than 30 to 45 minutes in a normal delivery. The normal presentation for a single lamb is two front feet with the head resting on them — when you look at the vulva during active straining, you should see two hooves with the pads facing down (indicating a forward presentation) and the nose or muzzle just behind them.

Once the lamb begins to emerge, delivery of the shoulders is the critical point — the shoulders are the widest part of the lamb and the most common site of obstruction. If the shoulders are through, the rest of the body follows quickly. From appearance of the feet to full delivery in a normal birth: 15 to 30 minutes of progressive straining and advancement. A ewe making good progress and the lamb advancing with each contraction needs no assistance. A ewe straining hard for more than 30 to 45 minutes without visible progress — or with the lamb presented but not advancing despite obvious effort — needs investigation.

Following the birth of the lamb, the ewe immediately begins vigorous licking — this stimulates the lamb's breathing and circulation, helps dry and warm the lamb, and crucially, imprints the ewe's olfactory bond to the lamb. Do not interfere with this bonding process unless there is a specific welfare reason. A ewe that is licking her lamb vigorously within five minutes of delivery is establishing the bond on which the lamb's survival depends. Step back and observe. The lamb should be attempting to stand within 15 to 20 minutes and should be actively seeking the teat within 30 to 45 minutes of birth. If these milestones are met, the pair is bonding normally.

Twin and triplet deliveries follow the same pattern, with the interval between lambs typically five to thirty minutes. The ewe may stand, circle, and briefly neglect the first lamb while beginning to deliver the second — this is normal. The concern arises when the ewe becomes exclusively focused on one lamb while ignoring the other, which is the beginning of mismothering and requires prompt management (see neonatal care section).

Dystocia (difficult birth) contributes to approximately 10 to 15% of lamb mortality and is more common than most producers realise, because many dystocic cases resolve without human intervention and are never identified — the lamb may be lost quietly in the paddock without the producer seeing the birth attempt. Building the confidence and skill to assist safely is one of the highest-return lambing skills available.

The threshold for investigation: any ewe that has been in active straining (visible abdominal contractions) for more than 30 to 45 minutes without producing a lamb, or any ewe in obvious distress (grinding teeth, repeatedly lying down and getting up, looking at her flank). Approach quietly, catch and restrain the ewe (kneel behind her and hold her against your bent knee, or tip onto her side), wash your hands thoroughly, and apply generous obstetrical lubricant before any internal examination.

The most common malpresentations in sheep:

Head back (both feet present, head turned back over the shoulder or down between the front legs): the most common malpresentation in sheep. The lamb's head must come forward in line with the front legs before delivery can proceed. Cup the head gently in your palm, guide it forward and between the front legs, and ensure it is positioned correctly (head on the front legs, not alongside them) before applying traction. This often requires only moderate repositioning and is the malpresentation most likely to resolve with straightforward assistance.

One leg back (only one leg visible, or one leg back at the elbow with the other forward): bring the retained leg forward by cupping the hoof to protect the uterine wall, flexing the fetlock, and guiding the leg into the canal alongside the other leg. Ensure the pads of both hooves are facing down (front feet presentation) before applying traction.

Breech presentation (tail first, hocks back or hind feet first): a breech delivery is more urgent than a front-leg malpresentation because the umbilical cord compresses between the lamb's abdomen and the pelvis as delivery progresses — once this compression occurs, the lamb has a limited window (two to three minutes) to be delivered before it is asphyxiated. Delivery of a breech lamb needs to be rapid once the process begins. If hocks are back, flex them forward before beginning traction. Apply steady, firm traction downward and backward in line with the ewe's spine — do not jerk or apply sudden force.

Traction technique: apply traction only during contractions, not between them. Use controlled, steady pressure — not sudden jerks. Direction of pull should be backward and slightly downward (following the angle of the ewe's birth canal), not straight back. Use obstetrical ropes or straps on the lamb's front legs to distribute pressure rather than gripping the legs directly, which can cause fractures. If the lamb does not move with moderate sustained traction during a contraction, there is likely a further obstruction and a veterinary call is needed immediately.

When to call the vet: any situation where you cannot determine the presentation; where you have attempted correction and the lamb still cannot be delivered; where the lamb appears to be very large relative to the ewe's pelvis; where there are suspected multiple lambs entangled; where the ewe is exhausted or collapsing; or where you feel out of your depth. There is no shame in calling early — a veterinarian arriving at a live ewe with a reachable lamb has far more options than one arriving at a dead ewe after a prolonged unassisted obstruction.

Post-assistance care: if the birth required intervention, administer long-acting oxytetracycline to the ewe immediately (the most common post-delivery complication is metritis — uterine infection — and antibiotic cover significantly reduces this risk). Ensure the lamb is breathing (clear the nose and mouth of fluid if necessary), check the ewe is allowing the lamb to nurse, and monitor the pair closely for the next 12 hours.

The first 48 hours of a lamb's life are the most dangerous it will face. Approximately 70% of pre-weaning deaths occur in this window, and most of them — starvation, hypothermia, and mismothering — are addressable if you are watching closely enough to identify problems early and intervene effectively. The monitoring investment in the first 48 hours after birth has a higher return than almost any other lambing management activity.

Colostrum is the single most critical factor in neonatal survival. A lamb born with adequate passive immunity from colostrum can tolerate a significant range of environmental challenges. A lamb without colostrum is immunologically defenceless and physiologically fragile — it will die from exposure, starvation, or infection at rates that make early mortality appear "normal" to producers who have not experienced a well-managed lambing. The data on this is unambiguous: lambs that receive at least 200ml of colostrum in the first two hours of life have dramatically better survival rates than those that do not, even controlling for ewe nutrition and environmental conditions.

After any assisted delivery, check immediately that the lamb is nursing effectively — watch for the characteristic head-bobbing and tail-wagging that indicates active sucking. A lamb that is bumping the ewe but not attaching, or that is resting without having yet nursed 30 minutes after birth, may need assistance. Guide the lamb to the teat (steady the ewe, kneel beside her, and guide the lamb's mouth to a teat with colostrum already expressing from the tip). Squeeze a small amount of colostrum onto the lamb's lips to stimulate the rooting reflex.

Stomach tubing is a technique every serious sheep producer should master. It is the fastest and most reliable way to deliver colostrum to a lamb that is too weak to nurse, has been rejected, or is hypothermic. The equipment is simple: a small-bore flexible tube (3 to 5mm diameter, smooth tip) and a 50 to 100ml syringe. With the lamb held upright in a sitting position, pass the tube gently down the oesophagus — the tube goes in the left side of the mouth, not the right, and passes to the left of the trachea. The key safety check: once the tube appears to be in position, kink the tube and observe — if the lamb shows respiratory distress, coughs, or struggles violently, the tube may be in the trachea, which will flood the lungs. Withdraw and reposition. If the lamb is calm and swallowing, the tube is in the oesophagus. Deliver colostrum slowly — 50 to 60ml per kg bodyweight in the first tube feeding, ideally repeated at four to six hourly intervals for the first 24 hours.

Hypothermic lambs require specific treatment depending on their core temperature. Take the temperature rectally: a lamb above 37°C is normothermic; 32 to 37°C is mild hypothermia; below 32°C is severe hypothermia. For mild hypothermia in a lamb that can hold its head up: warm the lamb quickly (a towel-lined box under a heat lamp, a warming bag, or held inside your jacket), then stomach-tube with warm colostrum (38 to 40°C) before returning to the ewe. For severe hypothermia in a lamb that cannot hold its head up: warm first without feeding — a lamb at below 32°C cannot metabolise glucose normally, and administering colostrum before warming can cause hypoglycaemic collapse. Warm to above 37°C (one to two hours under a heat lamp), then stomach-tube with warm colostrum, then continue warming before returning to the ewe. Intraperitoneal glucose injection (20ml of 20% glucose solution, injected into the peritoneal cavity by an experienced handler) is a rapid life-saving intervention for severely hypoglycaemic lambs — ask your vet to demonstrate the technique.

Navel treatment is a simple but important task. Dip or spray the navel cord stump in 10% iodine solution within the first hour of birth. The navel is the primary entry point for joint-ill (polyarthritis) — caused by bacteria ascending the navel cord and seeding the joint spaces — which is one of the most common causes of chronic illness and culling in young lambs. A well-dried, iodine-treated navel becomes a non-issue. An untreated or damp navel in a contaminated lambing environment is a genuine welfare and production risk.

Mismothering — a ewe that has not accepted her lamb(s) — is addressed most effectively immediately after birth, before the bond has failed completely. Confine the ewe and lamb together in a small individual pen (a 1.5 by 2 metre pen is adequate) for 12 to 24 hours. Ensure the ewe cannot avoid the lamb in the small space, that the lamb nurses at least every two hours (which you may need to ensure by holding the ewe), and that both are warm and fed. Most ewes will accept their lambs within 24 hours of this treatment. Persistent refusal may require more extended confinement, assistance nursing for several days, or — in extreme cases — fostering the lamb onto another ewe or raising as a bottle lamb.

Lamb marking — the combination of tail docking, castration of ram lambs intended for slaughter or wool production, identification, and vaccination — is typically done at two to six weeks of age, when lambs are well enough established to handle the procedures but young enough that they heal quickly and recover rapidly. The timing balances two competing considerations: younger lambs handle the procedures better physically, but older lambs are easier to catch and process efficiently in a mob situation.

Tail docking is performed for hygiene and flystrike prevention reasons in wool breeds. The standard recommendation is to dock leaving enough tail to cover the vulva in ewes and equivalent length in rams — long enough to provide some protection to the perineal area, short enough to prevent dag accumulation. Excessively short docking removes the natural protection of the breech area and is associated with increased rectal prolapse rates. The two common methods are the elastrator ring (applied at birth, using a rubber ring that cuts off blood supply and causes the tail to slough within ten to fourteen days — appropriate if done in the first week of life but not after that due to pain) and the hot iron or gas-powered docking iron (fast and clean cauterisation — the standard method in commercial operations). Follow pain relief protocols for tail docking — injectable meloxicam at the registered dose significantly reduces the physiological stress response.

Castration of ram lambs is performed where the lamb is not intended for breeding. The elastrator ring method, applied in the first week of life, is the most practical for large numbers. After the first week, the bloodless castrator (Burdizzo) or surgical castration under local anaesthesia are appropriate methods. Pain relief (meloxicam) is recommended for all castration procedures, and is a requirement in some state codes of practice — check the current regulatory requirements in your jurisdiction. Lambs intended for feedlot finishing are sometimes left entire (un-castrated) where the finishing period is short enough to complete before secondary sex characteristics affect carcase quality — entire males grow faster and more efficiently than wethers, and the carcase premium can offset the additional management complexity.

Identification at marking includes application of the National Livestock Identification System (NLIS) ear tag — required for all sheep before they leave their property of birth — and any additional property identification. Ear tags should be applied according to the manufacturer's instructions, in the correct ear (check your state NLIS requirements, as state colour and position requirements vary), using clean, sharp equipment. Clean tagger blades between animals during periods of high disease risk (high CLA prevalence, for example). Record tag numbers against ewe identification where individual performance data is being collected.

First vaccination of lambs should be timed to the marking event where possible, reducing mob-handling events. Lambs from vaccinated ewes should receive their first 5-in-1 or 6-in-1 dose at four to eight weeks of age, with a second dose four weeks later (which can coincide with weaning). Lambs from unvaccinated ewes should receive their first dose as soon as practical after birth — the earlier the better in the absence of passive immunity from colostrum.

Internal parasite management at marking is appropriate in high-worm-risk situations. Lambs begin to become susceptible to barber's pole worm and other gastrointestinal parasites from approximately four to six weeks of age, when the passive immunity from colostrum begins to wane. FAMACHA scoring of lambs at marking (checking the conjunctival colour of the inner eyelid) is appropriate in high-challenge situations — pale lambs should be drenched; lambs with good conjunctival colour can be left untreated to maintain refugia. Avoid blanket drenching all lambs at marking as a routine — this is exactly the management practice that has driven resistance in barber's pole worm populations across eastern Australia over the past three decades.

Improving lamb survival from a current baseline to a meaningfully higher level requires a systematic, analytical approach rather than a collection of individual tactical improvements. Producers who achieve consistent improvement identify what is killing their lambs, address the primary causes in order of significance, and measure their results objectively. Those who try multiple uncoordinated interventions simultaneously cannot identify which are working, and often find themselves repeating the same analysis in subsequent seasons.

Post-mortem investigation of lamb deaths is the most direct and reliable way to determine cause of death. A fresh post-mortem (performed on a lamb within an hour or two of death) can typically distinguish: starvation/hypothermia/mismothering (lamb in poor condition, empty abomasum, evidence of inadequate colostrum intake — brown or yellow-stained abomasal contents are undigested colostrum; a clean abomasum indicates the lamb received no colostrum at all); dystocia (evidence of trauma, birth-related haemorrhage, or compression injuries); infectious causes (joint swelling, pneumonia lesions, enteritis); and congenital defects. A basic post-mortem examination requires no specialist equipment — a sharp knife, clean hands, and a reference guide. Ask your district veterinarian to run through the technique with you, or attend a lambing field day run by your state producer organisation.

Aim to post-mortem at least 80% of lamb deaths in the first two to three lambing seasons of a systematic improvement program. Recording cause of death on a simple tally sheet (starvation/hypothermia, dystocia, infectious, congenital defect, unknown) over a lambing season produces a mortality profile that drives the intervention priority. If 60% of deaths are starvation/hypothermia, the investment goes into ewe nutrition and lambing paddock quality. If 20% of deaths are dystocia, the response is breed selection for easier lambing and management of ewe body condition to avoid overly-large lambs. If 30% are infectious, the response is biosecurity and vaccination review.

Monitoring frequency is one of the highest-return variables in lambing management and the one most easily increased without capital investment. A producer who checks the lambing paddock twice a day compared to once a day will save measurably more lambs — primarily from the starvation/hypothermia/mismothering complex, where early intervention (warming a cold lamb, stomach-tubing a hungry lamb, confining a mismatched pair) has a high success rate and late intervention has a much lower one. In a commercial enterprise, this translates to whether you check at first light and mid-morning (both in the high-birth period), or just at mid-morning. The difference in time is modest; the difference in outcomes in a wet or cold lambing period can be significant.

Weather is the environmental variable most tightly correlated with acute lamb mortality events. Cold, wet, windy conditions — the classic "death triangle" described in sheep mortality research — can kill normothermic lambs within hours if the ewe:lamb pair does not achieve rapid, effective nursing and bonding. Wind chill in particular is underestimated: a 10°C day with a strong cold southerly and rain creates far worse conditions for neonatal lambs than a dry 5°C calm day. When cold, wet, windy conditions are forecast during the peak lambing period, increase monitoring frequency, have the lambing kit accessible, and consider moving ewes closest to delivery into a more sheltered paddock. Shelterbelts, hay bales used as windbreaks, and purpose-built lamb shelters (small, low structures that lambs can enter and shelter inside while ewes remain accessible outside) all reduce weather-related mortality in exposed situations.

Data tracking over multiple years is what separates producers who improve systematically from those who experience good years and bad years without understanding why. Measure: percentage of ewes lambing (lambing percentage); lambs born per ewe lambed (litter size, from scanning data); lambs marked per ewe joined (the most important single productivity metric, as it integrates conception rate, pregnancy survival, and neonatal survival); lamb deaths by cause (from post-mortems); and birthweight where practical (strongly associated with survival rates — lambs below 3.5kg have dramatically higher mortality than those at 4.5 to 5.5kg). Track these numbers year on year and your decision-making will be driven by evidence rather than intuition.