# Accelerated Lambing Systems: STAR and Other Frequent Lambing Schedules ## Key Takeaways - Accelerated lambing systems, such as the STAR model (five lambings in three years), aim to increase flock productivity by compressing lambing intervals to approximately 7.2 months, requiring precise management of ewe reproductive cycles through controlled breeding seasons and ram exposure. - Successful implementation necessitates selecting breeds with extended or year-round breeding potential (e.g., Dorset, Rambouillet, Finnsheep, hair sheep) and meticulous breeding management, including 35-day breeding periods and strict culling for fertility to maintain the compressed schedule. - Ewe nutrition and body condition are paramount, as ewes are often rebred while lactating; inadequate nutrition can impair fertility and prolong postpartum anestrus, compromising the accelerated schedule. - Flock productivity hinges on high ewe fertility and lamb survival rates, which can be lower than in traditional systems due to increased metabolic stress on ewes and potential challenges with seasonal lambing; ewe longevity may also be reduced. - Practical adoption requires evaluating flock genetics, assessing facility and labor capacity for year-round lambing, developing detailed breeding and health programs, and implementing rigorous record-keeping to monitor individual ewe and group performance metrics. --- Accelerated lambing systems are management programs designed to increase the frequency of lambing from the traditional once per year to three lamb crops in two years or five crops in three years. The STAR system, developed at the U.S. Sheep Experiment Station, is one of the most documented accelerated lambing schedules. This article explains the core principles of accelerated lambing, the STAR system structure, breeding management requirements, flock productivity expectations, and practical implementation considerations for sheep producers. ## At a Glance Accelerated lambing systems compress the lambing interval by shortening the time between breeding periods and managing ewe reproductive cycles through controlled breeding seasons, ram exposure, and sometimes hormonal interventions. The table below summarizes the three most common accelerated lambing schedules and their key characteristics. | System | Lambings per Year | Lambing Interval | Typical Breeding Groups | Key Management Requirement | |--------|-------------------|------------------|------------------------|---------------------------| | STAR | 5 lambings in 3 years | Approximately 7.2 months | 5 groups on 7-month rotation | Strict breeding schedule adherence | | Three lambings in 2 years | 1.5 | 8 months | 3 groups on 8-month rotation | Extended breeding season management | | Five lambings in 3 years | 1.67 | 7.2 months | 5 groups on staggered schedule | Continuous lambing oversight | The STAR system requires ewes to lamb every 7.2 months, which demands precise breeding management and high ewe fertility. Research on ewe fertility in the STAR accelerated lambing system has documented the reproductive performance of ewes managed under this schedule (PubMed, 1996, https://pubmed.ncbi.nlm.nih.gov/8818795). Producers considering accelerated lambing must evaluate their flock genetics, facilities, labor availability, and market timing before adopting any frequent lambing schedule. ## Understanding Accelerated Lambing Accelerated lambing means managing a sheep flock to produce more than one lamb crop per ewe per year. Traditional annual lambing produces one lamb crop per ewe each year. Accelerated systems aim for three lamb crops in two years or five crops in three years, which increases the number of lambs marketed per ewe annually. The biological basis for accelerated lambing relies on the ewe's potential to breed, conceive, lamb, and be rebred within a compressed timeframe. Sheep have a gestation period of approximately 147 days. After lambing, ewes experience a postpartum anestrus period before they can resume normal estrous cycles. The length of this postpartum interval depends on breed, nutrition, lactation status, and season. Accelerated lambing systems require ewes that can breed outside the natural fall breeding season. Breeds with extended or year-round breeding seasons, such as Dorset, Rambouillet, Finnsheep, and many hair sheep breeds, are better suited for accelerated schedules. Research on lambing performance of Morlam and Dorset ewes under accelerated lambing systems has examined how specific breeds respond to frequent lambing management (PubMed, 1986, https://pubmed.ncbi.nlm.nih.gov/3818458). The Food and Agriculture Organization of the United Nations provides resources on sheep production systems, including reproductive management strategies (FAO Animal Production and Health, https://www.fao.org/animal-production/en). Producers should consult these resources when evaluating accelerated lambing options. ## The STAR Accelerated Lambing System The STAR system is a specific accelerated lambing schedule that produces five lamb crops in three years. The system divides the flock into five breeding groups, each on a staggered schedule. Each group lambs every 7.2 months, which means each ewe lambs five times in three years. ### System Structure The STAR system uses five breeding groups, each assigned to a specific breeding and lambing window. The breeding periods are approximately 35 days long, followed by a 147-day gestation, then a 35-day lambing period. After lambing, ewes have a 35-day rest and rebreeding period before the cycle repeats. The schedule requires that each group of ewes is bred at a specific time of year. Because the system operates on a 7.2-month cycle, breeding and lambing occur in different seasons each year. This means some lambings will occur during winter, spring, summer, and fall over the three-year cycle. ### Breeding Group Management Each of the five breeding groups must be managed as a separate cohort. Ewes are assigned to a group and remain in that group for the duration of their productive life. Rams are rotated through the groups according to the breeding schedule. The breeding season for each group lasts approximately 35 days. Ewes that do not conceive during the breeding period are culled or moved to a different management system. Strict culling for fertility is essential for the STAR system to function effectively. Research on ewe fertility in the STAR accelerated lambing system has documented the reproductive outcomes of ewes managed under this schedule (PubMed, 1996, https://pubmed.ncbi.nlm.nih.gov/8818795). Producers should review this research when evaluating the STAR system for their operation. ### Lambing and Weaning Management Lambing occurs in concentrated 35-day periods for each group. This allows producers to focus labor and facilities on one group at a time. Lambs are typically weaned at 60 to 90 days of age, depending on the system design and market goals. The effect of weaning age on hair sheep lamb and ewe production traits in an accelerated lambing system in the tropics has been studied, showing that weaning age influences both lamb growth and ewe rebreeding performance (PubMed, 2016, https://pubmed.ncbi.nlm.nih.gov/27065285). Producers must balance lamb growth requirements with the need for ewes to regain body condition and resume estrous cycles before the next breeding period. ## Other Accelerated Lambing Schedules Several accelerated lambing schedules exist beyond the STAR system. Each schedule has different breeding intervals, group structures, and management requirements. ### Three Lambings in Two Years This schedule produces three lamb crops in two years, with a lambing interval of approximately 8 months. The flock is typically divided into three breeding groups, each lambing every 8 months. This schedule is less intensive than the STAR system and may be more manageable for producers with limited facilities or labor. The three lambings in two years schedule requires ewes to be bred three times in two years. Ewes must conceive within 35 to 45 days after lambing to maintain the 8-month interval. This schedule works best with breeds that have extended breeding seasons and good maternal traits. ### Five Lambings in Three Years This schedule is similar to the STAR system but may use different group structures or breeding periods. The goal is five lamb crops in three years, with a lambing interval of approximately 7.2 months. Some producers modify the schedule to fit their specific climate, market, or facility constraints. Research on productive and reproductive performance of Pelibuey sheep in an accelerated lambing system with three mating seasons per year has examined how hair sheep breeds respond to frequent breeding schedules (Elsevier, 2010, https://api.elsevier.com/content/abstract/scopus_id/78650690675). Producers should consider breed-specific research when selecting an accelerated lambing schedule. ### Modified Accelerated Schedules Some producers develop modified accelerated schedules that fit their specific operation. These modifications may include longer breeding periods, different weaning ages, or seasonal adjustments to avoid extreme weather during lambing. The role of private practitioners in accelerated lambing has been discussed in veterinary literature, highlighting the importance of veterinary involvement in designing and managing accelerated lambing programs (Elsevier, 1990, https://doi.org/10.1016/S0749-0720%2815%2930834-3). Producers should work with their veterinarian when developing modified accelerated lambing schedules. ## Breeding Management for Accelerated Lambing Successful accelerated lambing requires precise breeding management. Ewes must conceive within a narrow window after lambing to maintain the compressed lambing interval. ### Ram Management Rams must be fertile and ready for breeding at the scheduled times. Ram breeding soundness examinations should be conducted 30 to 60 days before each breeding period. Rams should be evaluated for physical soundness, semen quality, and libido. In accelerated lambing systems, rams may be used more frequently than in traditional annual breeding programs. Ram fertility can decline with heavy use, so producers should monitor ram condition and rotate rams if necessary. The USDA Agricultural Research Service provides information on sheep breeding and reproduction research (USDA ARS, https://www.ars.usda.gov/). ### Ewe Condition and Nutrition Ewes must be in appropriate body condition at breeding time. Body condition scores of 3.0 to 3.5 on a 5-point scale are generally recommended for breeding. Ewes that are too thin or too fat may have reduced fertility. Nutrition management is critical in accelerated lambing systems because ewes are often lactating when they are rebred. Ewes must receive adequate nutrition to support lactation, maintain body condition, and resume estrous cycles. The Merck Veterinary Manual provides guidance on [sheep nutrition](/knowledge/animal-farming/sheep/sheep-nutrition-feeding-for-health-and-productivity) and management (Merck Veterinary Manual, https://www.merckvetmanual.com/management-and-nutrition). ### Breeding Season Length Breeding periods in accelerated lambing systems are typically 35 to 45 days long. Shorter breeding periods concentrate lambing and simplify management, but they require high ewe fertility and ram fertility. Longer breeding periods allow more time for ewes to conceive but spread out lambing and may reduce the efficiency of the accelerated schedule. ### Estrus Synchronization Some producers use estrus synchronization to concentrate breeding and lambing. Synchronization protocols may involve progestogen sponges, prostaglandin injections, or melatonin implants. Research on the effect of accelerated lambing system with melatonin feeding on reproductive performance for 2 years in Suffolk sheep raised in Hokkaido has examined how melatonin affects reproductive outcomes in accelerated systems (Elsevier, 1999, https://doi.org/10.1262/jrd.45.283). Producers should consult with their veterinarian before implementing any estrus synchronization protocol. Hormonal treatments require careful timing, proper administration, and adherence to withdrawal periods for meat and milk. ## Flock Productivity in Accelerated Lambing Systems Accelerated lambing systems can increase the number of lambs marketed per ewe per year, but productivity depends on several factors including ewe fertility, lamb survival, and management quality. ### Lambing Rate and Lamb Survival Lambing rate in accelerated lambing systems is typically lower than in traditional annual lambing systems. Ewes that lamb every 7.2 months may have lower conception rates and smaller litter sizes than ewes that lamb annually. The cumulative effect of frequent lambing on ewe longevity must also be considered. Lamb survival is critical in accelerated lambing systems because each lamb represents a larger proportion of the annual production. Facilities must provide adequate shelter, nutrition, and health management for lambs born in different seasons. ### Ewe Longevity Ewes in accelerated lambing systems may have shorter productive lives than ewes in traditional annual lambing systems. The increased metabolic demands of frequent lambing and lactation can lead to earlier culling for fertility, health, or body condition problems. Opportunities for genetic evaluation of reproductive performance in accelerated lambing systems have been explored, suggesting that genetic selection for fertility and longevity is important in these systems (Elsevier, 2012, https://doi.org/10.1016/j.livsci.2012.05.022). Producers should select replacement ewes from dams that perform well in accelerated lambing systems. ### Lamb Growth and Marketing Lambs from accelerated lambing systems may be marketed at different times of the year than lambs from traditional systems. This can provide marketing advantages if prices are higher during certain seasons. However, lambs born in extreme weather conditions may have slower growth rates or higher mortality. The effect of weaning age on hair sheep lamb and ewe production traits in an accelerated lambing system in the tropics has shown that weaning age affects both lamb growth and subsequent ewe reproductive performance (PubMed, 2016, https://pubmed.ncbi.nlm.nih.gov/27065285). Producers should evaluate their market goals and adjust weaning ages accordingly. ## Practical Implementation Steps Implementing an accelerated lambing system requires careful planning and preparation. The following steps outline the process for transitioning from a traditional lambing system to an accelerated schedule. ### Step 1: Evaluate Flock Genetics Not all sheep breeds are suitable for accelerated lambing. Breeds with extended breeding seasons, good fertility, and strong maternal traits are preferred. Producers should evaluate their current flock genetics and consider crossbreeding or breed replacement if necessary. Research on lambing performance of Morlam and Dorset ewes under accelerated lambing systems has shown that breed selection influences reproductive success (PubMed, 1986, https://pubmed.ncbi.nlm.nih.gov/3818458). Producers should review breed-specific research when selecting genetics for accelerated lambing. ### Step 2: Assess Facilities and Labor Accelerated lambing systems require facilities that can accommodate lambing in different seasons. Adequate shelter, ventilation, and biosecurity measures are essential. Labor requirements are higher in accelerated systems because lambing occurs more frequently. Producers should assess their current facilities and labor availability before adopting an accelerated lambing schedule. The Natural Resources Conservation Service provides technical assistance for livestock facility planning (NRCS, https://www.nrcs.usda.gov/). ### Step 3: Develop a Breeding Schedule The breeding schedule must be developed based on the chosen accelerated lambing system. The schedule should specify breeding dates, lambing dates, weaning dates, and rebreeding dates for each group. Producers should use a calendar or computer program to track breeding and lambing dates. Accurate record keeping is essential for managing accelerated lambing systems. ### Step 4: Implement Health and Nutrition Programs Health and nutrition programs must be designed to support the increased metabolic demands of accelerated lambing. Vaccination schedules, parasite control programs, and nutrition plans should be adjusted for the compressed lambing interval. The USDA National Agricultural Library provides resources on animal health and welfare that can inform health management decisions (USDA NAL, https://www.nal.usda.gov/animal-health-and-welfare). Producers should work with their veterinarian to develop appropriate health programs. ### Step 5: Monitor and Adjust Accelerated lambing systems require ongoing monitoring and adjustment. Producers should track ewe fertility, lamb survival, lamb growth, and ewe longevity. Data should be used to make management decisions and improve system performance. ## Records and Measurements Accurate record keeping is essential for managing accelerated lambing systems. The following records should be maintained for each ewe and each breeding group. ### Individual Ewe Records Each ewe should have an individual record that includes identification number, breed, birth date, lambing dates, number of lambs born, number of lambs weaned, lamb weights, and culling date. These records allow producers to evaluate individual ewe performance and make culling decisions. ### Group Records Records should be maintained for each breeding group, including breeding dates, ram exposure dates, pregnancy diagnosis results, lambing dates, lambing rates, lamb survival rates, and weaning weights. Group records allow producers to evaluate the performance of each group and identify management problems. ### Productivity Metrics Key productivity metrics for accelerated lambing systems include: - Lambs born per ewe per year - Lambs weaned per ewe per year - Total weight of lambs weaned per ewe per year - Lamb survival rate - Ewe fertility rate - Ewe longevity These metrics should be calculated for each breeding group and for the entire flock. Comparing metrics across groups and over time helps producers identify trends and make management adjustments. ## Common Failure Patterns Accelerated lambing systems can fail for several reasons. Understanding common failure patterns helps producers prevent problems and make timely adjustments. ### Low Ewe Fertility Low ewe fertility is the most common cause of failure in accelerated lambing systems. Ewes that do not conceive within the breeding period disrupt the schedule and reduce productivity. Causes of low fertility include poor nutrition, inadequate body condition, disease, ram infertility, and breed limitations. Research on ewe fertility in the STAR accelerated lambing system has documented fertility rates and identified factors that influence reproductive success (PubMed, 1996, https://pubmed.ncbi.nlm.nih.gov/8818795). Producers should monitor fertility rates and investigate causes of low fertility. ### Poor Lamb Survival Lamb survival is often lower in accelerated lambing systems than in traditional systems. Lambs born in extreme weather conditions, lambs from ewes in poor body condition, and lambs from multiple births may have higher mortality rates. Producers should provide adequate shelter, nutrition, and health care for lambs. Lambing facilities should be designed to protect lambs from weather extremes and disease. ### Ewe Health Problems Ewes in accelerated lambing systems are under increased metabolic stress. Health problems such as pregnancy toxemia, hypocalcemia, mastitis, and parasitism can occur more frequently. Producers should monitor ewe health closely and provide appropriate preventive care. The Merck Veterinary Manual provides information on sheep health management and disease prevention (Merck Veterinary Manual, https://www.merckvetmanual.com/management-and-nutrition). Producers should work with their veterinarian to develop health management protocols. ### Management Errors Management errors such as incorrect breeding dates, inadequate nutrition, poor record keeping, and failure to cull unproductive ewes can cause accelerated lambing systems to fail. Producers should develop standard operating procedures and train workers to follow them consistently. ## Welfare and Safety Context Accelerated lambing systems raise welfare considerations that producers must address. The increased frequency of lambing and lactation places greater physiological demands on ewes. Producers must ensure that ewes have adequate nutrition, health care, and rest periods between lambings. ### Ewe Welfare Ewes in accelerated lambing systems should be monitored for body condition, health, and behavior. Ewes that lose excessive body condition, develop health problems, or show signs of stress should be removed from the accelerated schedule and managed in a traditional system or culled. The USDA National Agricultural Library provides resources on [animal welfare assessment](/knowledge/animal-farming/poultry/poultry-welfare-assessment-protocols-and-practical-implementation) and management (USDA NAL, https://www.nal.usda.gov/animal-health-and-welfare). Producers should incorporate welfare assessment into their management protocols. ### Worker Safety Sheep handling can pose safety risks to workers. Rams during breeding season, ewes protecting lambs, and large groups of sheep can be dangerous. Workers should be trained in safe sheep handling techniques and provided with appropriate personal protective equipment. ### [Food Safety](/knowledge/bacteria/livestock-bacteria/cooking-chicken-bacteria-prevention) Lambs from accelerated lambing systems must be managed to ensure food safety. Withdrawal periods for medications must be observed. Records of medication use should be maintained. The USDA Food Safety and Inspection Service provides guidance on food safety requirements for sheep producers. ## Professional Escalation Criteria Producers should seek professional assistance when they encounter problems that exceed their expertise. The following situations warrant consultation with a veterinarian, animal scientist, or extension specialist. ### Veterinary Consultation Producers should consult a veterinarian when: - Ewe fertility rates fall below acceptable levels - Lamb mortality rates exceed 15 percent - Ewes show signs of metabolic disease - Rams fail breeding soundness examinations - Disease outbreaks occur in the flock The role of private practitioners in accelerated lambing has been discussed in veterinary literature, emphasizing the importance of veterinary involvement in these systems (Elsevier, 1990, https://doi.org/10.1016/S0749-0720%2815%2930834-3). Producers should establish a relationship with a veterinarian experienced in sheep production. ### Nutrition Consultation Producers should consult a nutritionist when: - Ewes fail to maintain adequate body condition - Lamb growth rates are below targets - Feed costs are excessive - Ration formulations need adjustment ### Extension Assistance Producers should contact their local extension service when: - They are considering adopting an accelerated lambing system - They need assistance with record keeping or data analysis - They want to evaluate the economic feasibility of accelerated lambing - They need information on breed selection or management practices ## Frequently Asked Questions ### What is accelerated lambing? Accelerated lambing is a management system that produces more than one lamb crop per ewe per year. Traditional annual lambing produces one lamb crop per year. Accelerated systems aim for three lamb crops in two years or five crops in three years. The STAR system is one of the most documented accelerated lambing schedules, producing five lamb crops in three years. ### How does the STAR accelerated lambing system work? The STAR system divides the flock into five breeding groups, each on a staggered schedule. Each group lambs every 7.2 months, producing five lamb crops in three years. The system uses 35-day breeding periods followed by 147-day gestation and 35-day lambing periods. Ewes that do not conceive during the breeding period are culled. ### What sheep breeds are best for accelerated lambing? Breeds with extended or year-round breeding seasons are best for accelerated lambing. Dorset, Rambouillet, Finnsheep, and many hair sheep breeds such as Pelibuey and Katahdin are commonly used. Research on lambing performance of Morlam and Dorset ewes under accelerated lambing systems has examined breed-specific responses (PubMed, 1986, https://pubmed.ncbi.nlm.nih.gov/3818458). ### How many lambs can I expect per ewe per year in an accelerated lambing system? The number of lambs per ewe per year depends on ewe fertility, litter size, and lamb survival. In a well-managed accelerated lambing system, producers may achieve 1.5 to 2.0 lambs weaned per ewe per year. However, individual farm results vary based on genetics, nutrition, health management, and environmental conditions. ### What are the main challenges of accelerated lambing? The main challenges include low ewe fertility, poor lamb survival, increased metabolic stress on ewes, higher labor requirements, and the need for precise management. Producers must have good facilities, adequate nutrition, and strong record-keeping systems to succeed with accelerated lambing. ### How does weaning age affect accelerated lambing systems? Weaning age influences both lamb growth and ewe rebreeding performance. Earlier weaning allows ewes more time to regain body condition before the next breeding period, but lambs may need more intensive management. Research on the effect of weaning age on hair sheep lamb and ewe production traits in an accelerated lambing system has examined these trade-offs (PubMed, 2016, https://pubmed.ncbi.nlm.nih.gov/27065285). ### Can accelerated lambing work in all climates? Accelerated lambing can work in various climates, but producers must adapt the system to local conditions. Extreme heat or cold can affect ewe fertility and lamb survival. Facilities must provide adequate shelter for lambing in different seasons. Research on productive and reproductive performance of Pelibuey sheep in an accelerated lambing system in the tropics has shown that hair sheep breeds can perform well in warm climates (Elsevier, 2010, https://api.elsevier.com/content/abstract/scopus_id/78650690675). ### How do I transition my flock to an accelerated lambing system? Transitioning to an accelerated lambing system requires evaluating flock genetics, assessing facilities and labor, developing a breeding schedule, implementing health and nutrition programs, and monitoring performance. Producers should start with a small group of ewes to test the system before expanding to the entire flock. Consulting with a veterinarian and extension specialist is recommended. ## Related Farming Guides - [Systems Biology](/blog/news/systems-biology) - [Dairy Cow Cooling System Management](/knowledge/animal-farming/dairy-cattle/dairy-cow-cooling-system-management) - [Carp Farming Pond Production Feeding And Harvest Management](/knowledge/animal-farming/aquaculture/carp-farming-pond-production-feeding-and-harvest-management) - [Bale Grazing With Sheep Site Selection And Nutrient Management](/knowledge/animal-farming/sheep/bale-grazing-with-sheep-site-selection-and-nutrient-management) - [Catfish Farming Managing The Production Cycle From Stocking To Harvest](/knowledge/animal-farming/aquaculture/catfish-farming-managing-the-production-cycle-from-stocking-to-harvest) ## Related Clinical & Scientific Guides * [Sheep Grazing Lease: Terms, Rates, and Legal Considerations](/knowledge/animal-farming/sheep/sheep-grazing-lease-terms-rates-and-legal-considerations) * [Sheep Breed Selection for Meat, Wool, Dairy, and Low-Input Systems](/knowledge/animal-farming/sheep/sheep-breed-selection-for-meat-wool-dairy-and-low-input-systems) * [Sheep Barn Flooring for Hoof Health: Best Materials and Practices](/knowledge/animal-farming/sheep/sheep-barn-flooring-hoof-health-materials-practices) ## References and Further Reading - [www.ars.usda.gov](https://www.ars.usda.gov/) - [www.nrcs.usda.gov](https://www.nrcs.usda.gov/) - [www.merckvetmanual.com](https://www.merckvetmanual.com/management-and-nutrition) - [FAO Animal Production and Health](https://www.fao.org/animal-production/en). Food and Agriculture Organization of the United Nations. - [Animal Health and Welfare](https://www.nal.usda.gov/animal-health-and-welfare). USDA National Agricultural Library. - [36th International Symposium on Intensive Care and Emergency Medicine : Brussels, Belgium. 15-18 March 2016.](https://pubmed.ncbi.nlm.nih.gov/27885969). Critical care (London, England), 2016. - [Effect of weaning age on hair sheep lamb and ewe production traits in an accelerated lambing system in the tropics.](https://pubmed.ncbi.nlm.nih.gov/27065285). Journal of animal science, 2016. - [Ewe fertility in the STAR accelerated lambing system.](https://pubmed.ncbi.nlm.nih.gov/8818795). Journal of animal science, 1996. - [Lambing performance of Morlam and Dorset ewes under accelerated lambing systems.](https://pubmed.ncbi.nlm.nih.gov/3818458). Journal of animal science, 1986. - [Electronic antihemocoagulation.](https://pubmed.ncbi.nlm.nih.gov/3814714). Biomaterials, medical devices, and artificial organs, 1986. - [Progress on CRISPR-Cas gene editing technology in sheep production.](https://pubmed.ncbi.nlm.nih.gov/39275869). Yi chuan = Hereditas, 2024. - [Productive and reproductive performance of Pelibuey Sheep in an accelerated lambing system with three mating season per year](https://api.elsevier.com/content/abstract/scopus_id/78650690675). Zootecnia Tropical, 2010. - [Effect of accelerated lambing system with melatonin feeding on reproductive performance for 2 years in Suffolk sheep raised in Hokkaido](https://doi.org/10.1262/jrd.45.283). Journal of Reproduction and Development, 1999. - [Opportunities for genetic evaluation of reproductive performance in accelerated lambing systems](https://doi.org/10.1016/j.livsci.2012.05.022). Livestock Science, 2012. - [The role of private practitioners in accelerated lambing.](https://doi.org/10.1016/S0749-0720%2815%2930834-3). Veterinary Clinics of North America Food Animal Practice, 1990. > This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.