- Animal breeding plays an important role in helping livestock populations adapt to changing environmental conditions. Across the world, livestock production systems are increasingly affected by climate change, rising temperatures, irregular rainfall, droughts, changing feed availability, emerging diseases, and shifts in farming practices. These environmental changes influence animal growth, reproduction, health, productivity, and survival. Traditional breeding programs often focused primarily on improving production traits such as milk yield, meat quality, growth rate, egg production, and reproductive performance under relatively stable conditions. However, modern livestock production requires a broader approach that considers how animals perform across different environments and how effectively they respond to environmental stress. Breeding animals for changing environments aims to develop livestock populations that maintain acceptable productivity, health, fertility, and welfare under a wide range of environmental conditions.
- The relationship between animal genetics and the environment is central to this breeding approach. An animal’s performance is influenced by its genetic makeup, the environment in which it lives, and the interaction between these two factors. Environmental conditions include temperature, humidity, nutrition, water availability, housing, disease exposure, management practices, and the quality of available feed. Animals with similar genetic potential may perform very differently when raised under different conditions. For example, a high-producing dairy cow may perform exceptionally well in a well-managed farm with effective cooling systems and abundant high-quality feed, but its milk production and reproductive performance may decline substantially in a hot environment with limited nutrition. In contrast, an animal with greater heat tolerance and lower maintenance requirements may sustain more consistent performance under challenging conditions. Understanding these differences helps breeders identify animals whose genetic characteristics are appropriate for the environments in which their offspring will be raised.
- Genotype–environment interaction is one of the most important concepts in breeding animals for changing environments. This interaction occurs when the relative performance of different genotypes changes across environments. Some animals may rank highly under favorable conditions but perform poorly under stressful conditions, while others may show moderate production in favorable environments and maintain relatively strong performance under environmental challenges. When the ranking of animals changes between environments, selecting breeding animals based only on performance in one location can lead to undesirable results in another. Breeding programs therefore need to evaluate animals across representative environmental conditions and determine whether particular genotypes are broadly adapted or better suited to specific production systems. This information allows breeders to make more accurate selection decisions and reduce the risk of developing animals that perform well only under narrow conditions.
- Heat tolerance is becoming an increasingly important breeding objective because high temperatures and humidity can reduce livestock productivity and compromise animal welfare. Heat stress affects feed intake, metabolism, immune function, fertility, milk production, growth, and survival. Animals differ genetically in their ability to regulate body temperature and maintain normal physiological functions during hot weather. Traits such as body temperature, respiration rate, sweating capacity, coat characteristics, and recovery after heat exposure can provide information about heat tolerance. Breeding programs can use these traits alongside production records to identify animals that combine useful productivity with the ability to withstand high temperatures. For example, selecting dairy cattle for both milk production and heat tolerance may help maintain productivity in warmer regions. In beef cattle, poultry, sheep, and goats, breeding for improved thermal regulation can also contribute to more resilient production systems.
- Adaptation to limited feed and water availability is another major objective in breeding livestock for changing environments. Droughts, irregular rainfall, soil degradation, and changing growing seasons can reduce pasture quality and increase the cost of supplementary feed. Animals that require large quantities of high-quality feed may become difficult to maintain when resources are limited. Breeding programs can therefore consider feed efficiency, nutrient utilization, body condition maintenance, survival, and reproductive performance during periods of nutritional stress. Feed efficiency is particularly important because it influences the amount of feed required to produce a unit of milk, meat, or eggs. However, efficiency should not be evaluated in isolation. Animals must also maintain adequate health, fertility, growth, and welfare. Breeding for resource efficiency should aim to improve production while reducing unnecessary demands on feed and water resources.
- Local livestock breeds often possess valuable adaptations to the environments in which they developed. Over many generations, natural selection and traditional breeding practices have helped some local populations develop tolerance to heat, resistance or resilience to particular diseases, the ability to use low-quality forage, and the capacity to survive under challenging management conditions. These characteristics can be especially important in smallholder farming systems and regions where veterinary services, high-quality feed, and climate-control infrastructure are limited. Although some local breeds may produce less milk or meat than specialized commercial breeds under intensive conditions, they may offer important advantages under harsh environmental conditions. Conservation and careful evaluation of local genetic resources can therefore support long-term breeding strategies. Crossbreeding programs may also combine the productive potential of specialized breeds with the environmental adaptation of local breeds, provided that breeding objectives, crossbreeding levels, and management requirements are carefully planned.
- Disease resistance and immune resilience are also important when breeding animals for changing environments. Climate change can alter the distribution, seasonal activity, and transmission patterns of parasites, insects, and infectious disease agents. Changes in temperature and rainfall may expose livestock populations to health challenges that were previously uncommon in their production regions. Genetic differences in disease susceptibility, immune responses, and the ability to recover after infection can influence productivity and survival. Breeding animals with improved resistance to important diseases may reduce economic losses and support animal welfare. However, disease resistance is often complex, involving many genes and interactions with nutrition, vaccination, management, and pathogen exposure. Effective breeding programs therefore combine genetic selection with biosecurity, veterinary care, disease surveillance, and appropriate management practices.
- Reproductive performance must also be considered when developing animals for changing environments. Heat stress and nutritional shortages can reduce conception rates, disrupt reproductive cycles, impair semen quality, and increase pregnancy losses. These effects can reduce the number of offspring produced and slow genetic progress within a herd or flock. Breeding programs that focus only on production traits may overlook the importance of fertility and reproductive stability under environmental stress. Including traits such as conception rate, calving interval, pregnancy success, survival of young animals, and the ability to reproduce under challenging conditions can improve the overall resilience of livestock populations. Such selection should be based on reliable records collected under the environmental conditions relevant to the target production system.
- Modern genomic technologies have expanded the opportunities for breeding animals suited to changing environments. Genomic selection uses information from markers distributed throughout the genome to estimate the genetic merit of breeding candidates. When genomic data are combined with performance records, pedigree information, and environmental measurements, breeders can identify animals that carry favorable combinations of genes for productivity, adaptation, and resilience. Genomic approaches are particularly useful for traits that are difficult or expensive to measure directly, including some measures of disease resistance, heat tolerance, and resilience to nutritional stress. However, genomic predictions are most useful when the reference population represents the breeds, production systems, and environmental conditions in which selection decisions will be applied. If genomic evaluations are developed under one set of conditions and used in very different environments, their accuracy may decline.
- Environmental data can improve the accuracy of genetic evaluation by helping breeders account for the conditions in which animals are raised. Information about temperature, humidity, rainfall, altitude, feed availability, disease exposure, and management systems can be linked with animal performance records. Statistical models can then distinguish genetic differences from environmental effects and identify animals whose performance is more stable across changing conditions. Reaction-norm models are one approach used to describe how an animal’s genetic performance changes along an environmental gradient. For example, these models can help estimate which dairy cows maintain milk production as heat load increases and which animals are more sensitive to rising temperatures. This information allows breeding organizations to select for both production potential and environmental responsiveness.
- Precision livestock farming can further support breeding decisions by providing detailed information about animal health, behavior, and physiological responses. Wearable sensors, automated milking systems, activity monitors, body-temperature measurements, and environmental monitoring devices can generate large amounts of data under commercial farming conditions. These records can help identify animals that maintain feed intake, activity, fertility, and production during environmental stress. Repeated measurements are especially valuable because resilience is not simply the ability to perform well at one moment. It also involves the ability to cope with a challenge, maintain essential biological functions, and recover when conditions improve. Combining sensor data with pedigree and genomic information may help researchers develop more reliable indicators of resilience for future breeding programs.
- Breeding animals for changing environments also requires careful consideration of the balance between productivity and robustness. Highly specialized animals may achieve excellent production under favorable conditions but become more vulnerable when environmental conditions deteriorate. Robust animals are generally able to maintain essential functions across a range of conditions, although robustness does not necessarily mean that they have the highest production in every environment. A successful breeding program should define the desired balance between output, adaptability, health, fertility, longevity, and welfare according to the needs of the production system. In some intensive systems, improving heat tolerance while maintaining high production may be the priority. In extensive systems, survival, walking ability, disease resistance, and the efficient use of variable forage resources may be more important.
- The conservation of genetic diversity is essential for long-term adaptation. Environmental conditions are likely to continue changing, and future challenges may differ from those currently experienced by livestock populations. If breeding programs rely too heavily on a small number of elite animals, genetic diversity may decline and the capacity to respond to new challenges may be reduced. Maintaining diverse breeds and lines preserves genetic variation that may become valuable under future environmental conditions. Conservation strategies can include maintaining live populations, preserving semen and embryos, recording breed characteristics, and documenting the environmental conditions in which animals perform well. Genetic diversity should be managed alongside genetic improvement so that immediate productivity gains do not undermine the long-term adaptability of livestock populations.
- Economic and social factors also influence the success of environmental breeding programs. Farmers need animals that match their local resources, management practices, market requirements, and production goals. A genetically improved animal may not deliver its full potential if it requires feed, water, housing, or veterinary services that are unavailable or unaffordable. Breeding objectives should therefore be developed with input from farmers, veterinarians, breeding organizations, researchers, and other stakeholders. Regional breeding strategies may be more effective than a single universal approach because environmental conditions and production systems differ substantially among regions. Extension services and accessible performance-recording systems can help farmers identify suitable breeding stock and apply genetic improvement strategies in practical settings.
- One major challenge is that many traits associated with environmental resilience are difficult to measure consistently. Heat tolerance, disease resistance, recovery after stress, and performance stability may require repeated observations over time. Environmental stress can also affect animals differently depending on age, sex, physiological stage, nutrition, and management. These factors make it important to collect high-quality data from sufficiently large and diverse populations. Researchers must also avoid selecting for apparent tolerance when animals are simply experiencing less exposure to stress or receiving better management. Standardized recording methods and appropriate statistical models are needed to separate these effects and produce reliable breeding values.
- Another challenge is the time required to achieve genetic change. Selective breeding improves populations over generations, so it cannot replace immediate measures needed to protect animals from severe heat, drought, disease, or food shortages. Shade, ventilation, cooling systems, reliable water supplies, balanced nutrition, vaccination, parasite control, and suitable housing remain essential. Genetic improvement works best as part of an integrated adaptation strategy that combines long-term breeding decisions with short-term management measures. This approach can reduce vulnerability while supporting sustainable livestock production.
- Future breeding programs are likely to place greater emphasis on adaptive traits as climate conditions become more variable. Advances in genomic analysis, artificial intelligence, sensor technologies, and environmental modelling may improve the identification of animals that perform reliably across different conditions. Breeders may increasingly use multi-trait selection indices that combine production, fertility, disease resistance, heat tolerance, feed efficiency, longevity, and welfare-related traits. Such indices can help ensure that selection decisions reflect the overall goals of sustainable livestock production rather than maximizing a single characteristic. International collaboration and the sharing of genetic and environmental data may also improve breeding strategies, particularly for regions facing similar environmental pressures.
- Breeding animals for changing environments is therefore an important component of climate adaptation and sustainable animal agriculture. By combining conventional selection, genomic technologies, environmental data, and conservation of genetic diversity, breeders can develop livestock populations that remain productive and healthy under increasingly variable conditions. The most effective strategies will recognize that adaptation differs among breeds, species, regions, and production systems. They will also balance productivity with fertility, disease resistance, animal welfare, and the efficient use of natural resources. As environmental challenges continue to evolve, breeding programs that prioritize both genetic improvement and long-term resilience will be essential for supporting farmers, protecting livestock, and maintaining reliable food production.
