Maximising Lamb survival at lambing factsheet

The Moredun Foundation News Sheet Vol. 8 | No. 8 | November 2025

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Maximising Lamb Survival at Lambing

Sarah Thomson, PhD, MRes, BSc (hons) Moredun Research Institute Sharon Brown, BVM&S, MSc, MRCVS Moredun Research Institute Thomas Tzelos, DVM, MSc, PhD, MRCVS Moredun Research Institute

key points Improving lamb survival starts a long time before lambing Feed ewe according to litter size Good ewe nutrition is important throughout pregnancy but especially in the final six-eight weeks Provide a good lambing site - Shelter helps to reduce risk of hypothermia Hygiene is critical and good hygiene can save a lot of heartache Aim for optimal birthweight according to breed and litter size (and your system) - Too light = reduced vigour, too heavy = birthing difficulties Ensure a good maternal bond (allow ewe to lick, lamb to stand and suckle in the first hour) Ensure good communication and ask advice from your vet – they know your farm and circumstances so can advise appropriately Keep good records so that you can identify issues early and make changes to minimise losses and benchmark performance

Introduction Some lamb losses around lambing time are, unfortunately, inevitable. However, improving survival rates is essential for both flock welfare and farm profitability.

High lamb mortality represents not only a major welfare issue but also a cost to farm efficiency and long-term sustainability.

The first month of life - particularly the first 48 hours to first week after birth - is the highest risk period for lambs. A recent study reported an average mortality rate of 10.4% in the first 21 days of life, with 9.5% of deaths occurring within the first week of life1. Key risk factors include difficult births (dystocia), weak lambs, poor maternal behaviour, poor hygiene at housing, predation and inadequate colostrum intake (whether through poor quality, insufficient quantity, or delays in ingestion)2.

The first step in tackling lamb losses is to review and analyse farm records.

Comparing scanning, lambing, and rearing percentages over time, and against national benchmarks3, helps identify where losses are occurring and where action should be focused.

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Strong foundations in basic husbandry are essential for neonatal survival. A clear plan covering breeding management, ewe nutrition, colostrum supply, infection control, and shelter provides the best starting point for maximising lamb survival.

1

https://ahdb.org.uk/development-of-an-integrated-neonatal-survival-and-sustainable-antibiotic-plan

2

S.H. Binns, I.J. Cox, S. Rizvi, L.E. Green, Risk factors for lamb mortality on UK sheep farms, Preventive Veterinary Medicine, Volume 52, Issues 3–4, 2002, Pages 287-303, ISSN 0167-5877, doi.org/10.1016/S0167-5877(01) 00255-0 3

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https://ahdb.org.uk/key-performance-indicators-kpis-for-lamb-sector

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Breeding Decisions made at breeding time can have a major influence on lamb survival months later. Careful selection of parents, together with appropriate breeding management, can reduce the risk of losses around lambing.

Choosing rams with Estimated Breeding Values (EBVs) for traits linked to lamb survival, such as lambing ease, birth weight, and maternal ability and avoiding sires that consistently produce very large or very small lambs can reduce problems at lambing.

It is important to only retain ewes with a proven history of good mothering ability, adequate milk supply, and minimal lambing assistance. Keeping records each year and culling any ewes with repeated issues such as poor mothering, low colostrum production or lambing difficulties will improve your flock.

Aim for the correct body condition score (BCS) at tupping (typically 2.5 – 3.0, depending on breed) to improve fertility, lamb viability and colostrum quality. It is important to monitor BCS throughout gestation, overly fat or underweight ewes are at higher risk of metabolic disease (i.e. twin lamb) and lambing complications (dystocia).

Test and manage breeding stock for infectious diseases such as toxoplasmosis, enzootic abortion, and Border disease, which can compromise lamb survival before birth. Vaccination and biosecurity at breeding time are essential to protect lamb viability.

By planning breeding with survival in mind, farmers can influence lamb vigour, ease of birth and ewe mothering ability long before lambing season begins.

Nutrition Ewe nutrition during pregnancy plays a critical role in lamb survival. Both under- and overfeeding can compromise ewe health, foetal development and lamb viability.

During mid-pregnancy aim to maintain steady growth of the foetus and placenta by keeping the ewes condition stable. Nutrition in this period sets up placental size and function, which directly affects lamb birth weight and survival.

The last six to eight weeks of gestation are the most critical. Group ewes to ensure you are feeding according to the number of lambs the ewe is carrying. Over-feeding can lead to a higher birthweight increasing the risk of dystocia while under-feeding may result in a low birthweight increasing the risk of hypothermia and poor milk yield. Blood sampling a proportion of each group around 3 - 4 weeks prior to lambing, can determine the metabolic profile and mitigate any nutritional stress.

Ewe rations must be formulated to minimise the risk of metabolic disease in the ewe which may jeopardise the pregnancy (e.g. twin lamb disease). Regular condition scoring and strategic supplementation can reduce these risks.

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Colostrum Colostrum is not only nutrientially rich but filled with immunoglobulins. Due to the structure of the ruminant placenta all ruminant livestock are born without any antibodies. Therefore, young ruminants depend on the transfer of antibodies from maternal (or artificial if maternal not available) colostrum from their gut to their bloodstream within 18 hours of birth. This early transfer of antibodies ensures protection against diseases in the first weeks of life. When lambs do not receive sufficient antibodies then they suffer from what is known as ‘failure of transfer of passive immunity’. This increases the risk of morbidity and mortality.

The three Q’s: Quality, Quantity, Quickness • Quality: Ensure ewes are well-nourished pre-lambing to maximise antibody levels. Test your colostrum to ensure that it is at least 50g/l of IgG measured with a colostrometer of refractometer (results might vary depending on the test method and region).

• Quantity: Lambs should ideally suckle within the first 1-2 hours. As a guideline, aim for at least 50ml/kg within the first 2 hours, and 200ml/kg within the first 24 hours.

• Quickness: Absorption of antibodies is most efficient in the first 4 - 6 hours of life and declines rapidly thereafter.

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Maintain good hygiene during colostrum collection and storage to prevent bacterial contamination. Fresh colostrum should be used within one hour or within three days if stored in a fridge. Clean, good quality colostrum can be frozen and used within 12 months. Before use, defrost in a warm water bath at less than 50oC. Never use a microwave or boiling water otherwise the antibodies will be destroyed.

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Hygiene Maintaining good hygiene during lambing is crucial for improving lamb survival and can help prevent many of the common diseases that affect neonatal lambs. Disease causing pathogens can be found and transported on lambing kit including pens, feeding equipment etc a well as on your own hands and boots. A good hygiene protocol will include the following: Lambing pens: regularly clean and disinfect lambing pens to prevent pathogens from being picked up by the newborn lamb through the mouth, navel or through wounds and abrasions; use fresh bedding and disinfect between occupants.

Hands/boots: always wear disposable gloves when assisting a ewe to lamb and when handling ill lambs to reduce pathogen transmission. Clean boots between groups and handle sick animals last after attending to healthy lambs.

Navels: dip the navel in iodine (or other recommended disinfectant) immediately after delivery and again four to six hours later to reduce infection risk.

Equipment: clean and disinfect all tools (stomach tubes, lambing aids, etc.) before and after use. Store the clean equipment in a dry area.

By following these hygiene protocols, farmers can improve lamb survival and overall flock health during the lambing season.

Infection Lambs are highly vulnerable to infectious disease in the first weeks of life, and even before!

Hygiene at lambing is of vital importance as lambs are particularly susceptible when immunity is low and environmental contamination high. Clean, dry bedding and good ventilation in lambing sheds are critical to reducing the spread of pathogens.

Regularly remove soiled bedding and disinfect pens between occupants.

Abortion Abortion not only causes the death of lambs before term, but Enzootic Abortion of Ewes (EAE), Toxoplasmosis and Campylobacter are also responsible for the birth of small, weakly lambs which are particularly susceptible to hypothermia and the other life-threatening diseases of early life. Where these infections pose a threat, vaccination of ewes is possible for EAE and toxoplasmosis, but this must be carried out between weaning and mating and no later than one month before the rams are put out with the ewes.

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Schmallenberg virus Schmallenberg virus (SBV) is associated with malformed lambs that are either born alive or dead at term or aborted following infection of the dam. Typical malformations include bent limbs and fixed joints, which may affect all limbs and the spine or only specific limbs or joints. Brain deformities such as hydranencephaly and damage to the spinal cord are also common. Contracted tendons is one of the most frequent birth defects caused by the virus.

Some animals appear normal at birth but exhibit neurological symptoms such as blindness, ataxia, recumbency, inability to suck or seizures. The type and severity of foetal deformities depend on the stage of pregnancy at which infection occurs. In sheep, it is not uncommon for only one lamb in a multiple birth to be affected, while the others remain normal.

Using insecticides can help lower the number of midges biting individual animals, but this approach has not proven effective for large-scale control. Delaying the breeding season until later in the year is likely the most practical strategy to reduce the risk of Schmallenberg virus infection. However, in years when frost arrives late, midge populations may remain high through October.

Watery Mouth Watery mouth is a bacterial infection affecting newborn lambs, usually within the first three days of life. It is caused by E. coli bacteria multiplying in the gut and releasing toxins, often due to insufficient colostrum intake, poor hygiene at lambing, or overcrowding. Even with treatment watery mouth is often fatal, making prevention through good colostrum management and hygiene essential.

Clostridial Disease Pulpy kidney and lamb dysentery are the main clostridial diseases affecting neonatal lambs. Clostridial diseases often strike suddenly, with little or no warning, and affected lambs are usually found dead rather than showing prolonged illness, so prevention is key. This relies on vaccinating ewes before lambing so they pass on protective antibodies through colostrum, ensuring lambs receive enough colostrum in the first hours of life, and maintaining good hygiene at lambing to reduce infection risk.

Joint/Navel Ill Wet navels can easily become infected with bacteria from the lambing environment, dip lamb navels promptly after birth with strong iodine solution (10%) or other suitable disinfectant, repeating if necessary to encourage them to dry up. This reduces the risk of joint ill and septicaemia.

Pasturellosis Causes septicaemia in young lambs and can be a common cause of sudden death in weaned lambs in the Autumn, as well as pneumonia in older sheep and mastitis in ewes. Vaccines for pasturellosis are available and often combined with clostridial diseases.

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Shelter Exposure is a major cause of neonatal lamb losses, particularly in outdoor lambing systems. Providing appropriate shelter helps reduce chilling, starvation, and predation.

It is important to pick a system that suits you and your needs as well as the type of sheep you have and the time of year you intend to lamb.

Indoor systems Indoor systems provide better protection from poor weather conditions for both sheep and staff as well as allowing pasture to rest. Housing sheep for lambing can also allow closer supervision of lambing ewes via in-person checks or CCTV systems. However, there are higher costs associated with indoor lambing as the risk of infectious diseases and mis-mothering is increased.

It is important to ensure sheds are well-ventilated but draught-free and that pens are mucked out/disinfected regularly.

Outdoor systems Outdoor lambing may suit hardier, native breeds better and can reduce the risk of infectious diseases as well as reducing feed and labour costs. Outdoor lambing can result in higher losses if there is poor weather and checking of stock can be tricker.

Fields selected for outdoor lambing should have either natural shelter such as hedgerows, banks, or woodland, or temporary shelters (bales, windbreaks, mobile huts) to provide additional protection in exposed areas. It is also important to ensure that there is enough forage available for newly lambed sheep to avoid mismothering or abandonment from hungry ewes.

Hypothermia and hypoglycaemia Lambs from well fed ewes are born with a supply of special (brown) fat which is metabolised immediately after birth, producing heat and energy which gets the lambs going. It is used up within a few hours, so if the lamb does not receive colostrum, then the lamb is at risk of starvation (hypoglycaemia). If the lamb does not receive sufficient energy (colostrum/milk replacer etc) then its body temperature will fall (hypothermia), and it will die if it is not spotted and cared for. Cold weather, but particularly the combination of wind and rain, will chill lambs very rapidly.

Important techniques to learn which can be used to save the life of a hypothermic lamb include the use of thermometer, stomach tube, warming box and, most importantly, the injection of dextrose (glucose) into the abdominal cavity. The supply of energy in this manner to starving, unconscious or semi-conscious lambs before they are warmed in a box, is vital to their survival. Ask your vet to show you how to do this.

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Detecting and Dealing with Hypothermic Lambs Any lamb which gives the slightest cause for concern should immediately have it’s temperature taken and be thoroughly towel dried if wet.

Temperature

37-39oC

Age of Lamb

Any age

Condition of Lamb

Able to swallow

Below 37oC > 5 hours old Head up and able to swallow

< 5 hours old

Head down and unable to swallow

Able to swallow

Provide energy with an injection of glucose into the body cavity

Feed by stomach tube

Warm the lamb back to just 37oC, checking it’s temperature every 20 minutes

Feed by stomach tube, then...

...if the lamb revives and is able to suck it’s dam effectively, keep them close to home for frequent observation

...if the lamb is still weak, keep it in an aftercare unit and feed it regularly by stomach tube until it is strong enough to rejoin it’s mother

Figure1: Detecting and dealing with hypothermic lambs

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Recording To understand where/why losses are occurring it is important to keep good records.

Records should include information on the number of ewes bred and to which tup, the number of empty ewes at scanning as well as the number of lambs scanned.

When lambing starts the number of lambs born alive, dead or weak should be recorded as well as how easily the ewe lambed, the ewes mothering instinct and the lambs vigour. Recording doesn’t stop at lambing; it is also important to record the number of lambs turned out and the number weaned.

These data will allow you to work out which ewes are good mothers (the ones that have good mothering instinct and which lamb without assistance) and which should perhaps be culled. Same for the rams, if you know which tup sired your healthiest, hardiest lambs then you can make good decisions at tupping.

Knowing the number of ewes that are empty at scanning can indicate potential issues with a tup or a problem with nutrition. The number of lambs scanned compared to the number born alive indicates how many have been lost during pregnancy (maybe indicating a problem with infectious abortion) or nutritional deficiencies.

If you record the number of lambs turned out and/or weaned and compare it to the number of lambs born alive you can see how many lambs are lost in the first few days of life. This is often an indication of poor colostrum quality/uptake, hygiene or infectious diseases. The number of lambs weaned will show you how many lambs were lost in the first few months of life where the issues might be related to other health problems.

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Ongoing research at Moredun Syndromic Diagnostic Diseases in livestock often show similar clinical signs and can involve more than one pathogen at the same time, this can make diagnosis difficult or require multiple different tests.

Multiplex diagnostics can detect several different pathogens from a single sample, meaning faster results which, in turn, leads to quicker, more accurate treatment and management decisions. Faster diagnostic turnaround can also improve biosecurity and helps keep disease under control on farms.

Innovative Vaccines Some vaccines are difficult to produce in large quantities for commercial application, especially those requiring material from the pathogen itself. New approaches, using plant- or insect-based alternatives may be more efficient, cost-effective and scalable. The use of these alternatives could accelerate the availability of novel vaccines and avoid production shortfalls (as experienced with several existing vaccines), ensuring that farmers have reliable access to preventative tools when disease risks are highest.

Several pathogens can cause similar diseases (e.g. reproductive losses).

Moredun is working on multi-pathogen vaccines that protect against more than one threat in a single injection. Current research includes vaccines targeting both Chlamydia abortus and Toxoplasma gondii, improving convenience, reducing handling stress and optimising immunity.

Improving animal health through the use of vaccination, monitoring and management is vital to enhancing resilience in the face of climate change.

These measures not only protect livestock health but also support more sustainable, productive farming systems. Working with industry (SCOPS/COWS) to develop resources to aid in detection and control of parasitic diseases.

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