MISMOTHERING
- Sheep Advocate Australia
- 4 days ago
- 7 min read
Updated: 3 days ago
The Causes of Lamb Mortality in the Australian Sheep Industry
A Study of Known Causes, Systemic Neglect, and the Continued Failure to Prevent the Death of Millions of Lambs
Prepared by:
Sheep Advocate Australia
Abstract
Across Australia, lamb mortality remains one of the most significant and persistent welfare failures within the sheep industry. It is widely estimated that over 10 million lambs die each year between birth and marking, with the majority dying within the first days of life.
A large proportion of these deaths are attributed to what researchers describe as the Starvation–Mismothering–Exposure (SME) complex, a combination of factors involving maternal separation, starvation, low birth weight and environmental exposure.
The causes of lamb mortality have been extensively documented for more than fifty years. However, despite decades of research and industry awareness, large-scale neonatal losses remain embedded within Australian sheep production systems.
This report examines the causes of mismothering, the role of breeding immature ewes, the systemic pressures that contribute to lamb mortality, and the way industry language itself often obscures responsibility for these deaths.
1. Introduction
Australia maintains one of the largest sheep populations in the world and remains a global leader in wool and meat production. However, behind this production system lies a persistent and largely normalised welfare issue: the death of millions of newborn lambs every year.
Industry and research estimates indicate that more than 10 million lambs die annually shortly after birth, representing a significant proportion of animals born each year (Ipsen, AWI).
Most deaths occur within the first 72 hours of life, a period during which lambs are highly vulnerable to starvation, exposure and maternal separation (Meat & Livestock Australia).
These causes are collectively referred to in sheep research as the Starvation–Mismothering–Exposure (SME) complex, which has consistently been identified as the leading cause of lamb mortality in Australian flocks.
The problem is not new. Research identifying mismothering and starvation as key contributors to lamb death dates back to the 1960s and early 1970s, yet mortality levels remain largely unchanged across the industry.
2. Understanding Mismothering
Definition
“Mismothering” refers to the breakdown of the bond between ewe and lamb shortly after birth.
This may occur when:
the ewe fails to recognise the lamb
the ewe abandons the lamb
the lamb becomes separated from the ewe
the lamb is too weak to suckle
environmental conditions interfere with bonding
When this bond fails, lambs often die quickly due to starvation or exposure to cold and wind.
The phenomenon is typically grouped with starvation and environmental exposure as the SME complex, widely recognised as a dominant cause of neonatal mortality in sheep production.
Studies examining lamb deaths consistently show that starvation and exposure following maternal separation represent the largest single cause of lamb mortality.
3. Scale of Lamb Mortality in Australia
Lamb mortality in Australia is widely recognised as a major industry issue.
Research and industry reports estimate:
• More than 10 million lambs die annually between birth and marking (Ipsen, Australian Wool Innovation).
• In some conditions, mortality rates can reach 30–40% of lambs born.
• Most deaths occur within the first three days of life (MLA Lamb Survival Research).
These losses represent both an economic loss and a welfare crisis.
Industry sources estimate lamb mortality costs producers tens of millions of dollars annually, yet the scale of losses has remained consistent for decades.
4. Known Causes of Lamb Mortality
Research consistently identifies a set of interconnected causes contributing to mismothering and neonatal lamb deaths.
4.1 Low Birth Weight
Low birth weight is one of the strongest predictors of lamb mortality.
Small lambs are more likely to:
• struggle to stand
• fail to suckle
• lose body heat rapidly
• become separated from their mothers
Low birth weights are often associated with young ewes, multiple births, and poor maternal nutrition.
4.2 Environmental Exposure
Newborn lambs have limited ability to regulate body temperature.
Cold winds, rain and wet ground can rapidly lead to hypothermia, particularly when lambs fail to receive adequate colostrum from their mothers.
This is especially significant in southern sheep-producing regions such as Victoria, where lambing frequently occurs during cold and wet seasons.
Despite this, many sheep production systems provide little or no structural shelter for lambing animals.
4.3 Birth Complications (Dystocia)
Difficult births weaken both ewe and lamb and significantly increase mortality risk.
Research indicates dystocia accounts for a substantial portion of lamb deaths and frequently contributes to starvation and mismothering when lambs fail to nurse.
4.4 Multiple Births
Selective breeding has increased the number of twin and triplet lambs.
While this increases production output, it also increases mortality risk because:
• lambs are smaller at birth
• mothers must feed multiple lambs
• maternal bonding becomes more difficult
Twin and triplet lambs consistently show higher mortality rates than single lambs.
5. Breeding Immature Mothers
One of the most controversial production practices in the sheep industry is the breeding of very young ewes.
Many commercial systems breed sheep so they give birth at 12 months of age.
This means the ewe herself is still physically immature.
Research consistently shows ewe lambs and maiden ewes display:
• reduced maternal behaviour
• lower milk production
• higher lamb mortality rates
Breeding immature sheep increases total lifetime productivity but also increases neonatal losses.
6. Two-Tooth Ewes and Reduced Survival
Sheep aged around two years old, commonly referred to as two-tooth ewes, also show reduced reproductive success compared with mature sheep.
Studies demonstrate that maiden and two-tooth ewes experience:
• lower lamb survival
• reduced maternal ability
• increased mismothering events
Despite this knowledge, breeding young animals remains a common industry practice.
7. Ideal Breeding Age
Sheep reach full physical and maternal maturity later in life.
Research indicates that fully mature ewes aged approximately 4–5 years provide the most stable maternal performance, with improved:
• maternal bonding
• milk production
• lamb survival
However, waiting until sheep reach this age to begin breeding would reduce lifetime productivity.
For this reason, the industry generally prioritises production efficiency over biological maturity.
8. The Language of “Mismothering”
The widespread use of the term “mismothering” within sheep industry literature deserves critical examination.
The terminology frames lamb deaths as the result of maternal failure, suggesting that the ewe has failed to care for her lamb.
In practice, however, the conditions leading to mismothering are overwhelmingly created by human management decisions.
These include:
• breeding immature mothers
• lambing in harsh weather conditions
• low birth weights caused by production pressures
• large paddocks where animals cannot be monitored
• limited shelter for newborn lambs
Despite this, lamb deaths are frequently recorded simply as “mismothering”, a term that implicitly places responsibility on the ewe.
This framing serves several functions.
First, it normalises high mortality levels as a natural outcome of sheep behaviour.
Second, it shifts attention away from structural production practices that contribute to lamb deaths.
Third, it allows the industry to maintain systems that knowingly produce large-scale neonatal losses while attributing deaths to maternal behaviour rather than management decisions.
Sheep possess strong maternal instincts under natural conditions. When bonding fails in commercial production systems, it often reflects environmental and management pressures rather than maternal deficiency.
The continued use of the term therefore risks obscuring systemic causes of lamb mortality.
9. Systemic Production Pressures
Several production strategies contribute to ongoing lamb mortality.
Winter Lambing
Many flocks lamb during colder months to align lamb growth with spring pasture availability.
While economically efficient, this significantly increases exposure risk for newborn lambs.
Extensive Management Systems
Large paddocks and minimal monitoring mean that:
• birth complications may go unnoticed
• weak lambs receive no assistance
• mismothering events cannot be corrected
Genetic Selection for Productivity
Selective breeding for higher lambing percentages increases the number of multiple births and can contribute to smaller lambs and higher mortality.
10. A Problem Known for Decades
Research identifying mismothering and starvation as key causes of lamb mortality dates back more than half a century.
Studies from the 1960s and 1970s already recognised the starvation–mismothering–exposure complex as the dominant cause of lamb deaths.
Despite this long-standing knowledge, mortality levels remain embedded in modern production systems.
11. Ethical Implications
When an industry knowingly operates production systems where millions of newborn animals die every year, the issue cannot simply be described as unavoidable.
The causes of lamb mortality are well understood.
The technologies and management changes required to reduce deaths are also widely known.
The continued scale of losses therefore reflects a systemic prioritisation of production efficiency and financial return over animal welfare outcomes.
12. Conclusion
Mismothering remains one of the most significant contributors to lamb mortality in Australia.
The mechanisms driving these deaths - including immature mothers, low birth weight, exposure to harsh weather and extensive production systems - are well documented.
Yet despite decades of research, the industry continues to operate systems in which more than 10 million lambs die each year shortly after birth.
The terminology used to describe these deaths further complicates the issue.
By framing mortality under the label of “mismothering,” responsibility is often shifted onto the ewe, portraying lamb deaths as maternal failure rather than the predictable outcome of production practices.
In reality, the factors driving lamb mortality are largely the result of human decisions about breeding, management and production efficiency.
Until those systemic pressures are addressed, large-scale neonatal losses will remain a structural feature of the Australian sheep industry.
References
Dennis, S.M. (1964). Starvation/Mismothering: A Major Cause of Lambing Losses. Journal of the Department of Agriculture, Western Australia.
Ipsen, M. (Australian Wool Innovation). World’s Best Practice in Lamb Survival. Nuffield Farming Scholarship Report.
Meat & Livestock Australia. Lamb Survival Research Report.
Kenyon, P.R. et al. (2022). Breeding Ewe Lambs: An Australasian Perspective.
Murdoch University Research Portal. Lower Reproductive Rate and Lamb Survival in Maiden Ewes.
Hinch, G., Brien, F. Causes of Neonatal Lamb Mortality in Australian Flocks.
Bruce, M. et al. Impact of Lamb and Ewe Mortality Associated with Dystocia on Sheep Farms.
FOUR PAWS. Lamb Mortality in Australia Briefing Paper.
Birchip Cropping Group. Avoiding Mismothering and Starvation in Lamb Production.
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