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  • Breeding
    • Ewe reproduction
    • Ram reproduction
    • Breeding systems
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  • Lambing
    • Lambing systems
    • Getting ready
    • Lambing process
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  • Feeding
    • Nutrient requirements
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Lambing systems

A lambing system denotes when lambing will occur (what season or months), how often a ewe will lamb (annual vs. accelerated), and how and where lambing will occur (shed vs. pasture). There is no one "best" lambing system or way to raise sheep. Producers need to match the lambing system to their goals and objectives, resources, and marketing situation.


Early vs. Late Lambing

The first decision to make is when to lamb. There are advantages and disadvantages associated with lambing at different times of the year.

Early Lambing (winter-early spring)

Early lambing systems have several advantages. High on the list is labor availability. For producers that farm full-time, the winter is a time when labor is more readily available versus the spring when field work and planting begins. Lambs born early in the year are usually gone by the time summer comes.

Another advantage is marketing. Historically, lamb prices have been highest during the first half of the year, especially during the Easter period. As a result, lambs born in the winter are usually sold for higher prices than those born in the spring. Producers who lamb in the winter can usually carry more ewes on their pastures, since ewe feed requirements are only maintenance and lambs are not competing for a possibly limiting resource, pasture.

However, if lambing occurs during the winter months, adequate facilities are needed. Housing is a big consideration and overhead cost. Mastitis, scours, and pneumonia tend to be bigger issues with early lambing because sheep are confined into smaller areas. Early-born lambs are often creep fed and finished on concentrate rations. They usually grow faster than those born later in the year, but their cost of gain is usually higher.

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Late Lambing (April-May)

Late lambing has many advantages over early lambing and is gaining in popularity. With spring lambing, the sheep production cycle is synchronized with the forage production cycle, allowing for maximum use of forage resources. Late lambing takes optimal advantage of the spring flush of grass. On the other hand, for most of the winter, ewes can be maintained on a maintenance diet of relatively inexpensive hay or silage.

Spring lambing coincides with the natural breeding and lambing seasons. With spring lambing, breeding and lambing periods tend to be more condensed, because ewes and rams are most fertile during a fall mating season. Many ewes conceive during their first heat cycle and most will settle within two heat cycles, resulting in a short 35-day lambing period.

Another advantage is that ewes usually give birth to larger lamb crops. Even the breeds noted for out-of-season lambing will produce a 10 to 20 percent higher lamb crop in the spring than in the fall. Any breed of sheep can be raised in a late-lambing season.

The primary benefit to late lambing is reduced production costs: lower feed costs, less labor, and overhead. However, late lambing requires better pasture management than early lambing, since lambs are usually fed or finished on grass. Internal parasites and predators can be a significantly larger problem with late lambing programs.

Early spring and late summer conditions are the worst for parasite infestations. Highest predation typically occurs from late spring through September-October due to high feed requirements of raising the predators young and the fact that the sheep are on pasture during this time. It is essential that producers have a plans for dealing with both potential problems.

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Fall Lambing (September-November)

Fall lambing has several advantages over the previous systems. Late-gestation and lactation coincide with fall forage growth. Weather conditions are usually ideal for pasture lambing. There are fewer problems with parasites and predators with fall lambing. Lambs can usually be sold when prices are the highest.

However, fall lambing is a challenge because conception rates are much lower than with spring breeding. Less seasonal breeds are usually favored in a fall lambing program, although seasonal breeds can be primed to lamb in the fall using the ram effect, light control, and/or hormonal manipulation of the reproductive cycle.

From an industry standpoint, if more lambs were born in the fall, the supply of lamb year-round would be more even, resulting in more stable prices and steadier demand.

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Accelerated Lambing

Acclerated lambing is when ewes lamb more frequently than once a year. The purpose of accelerated lambing systems is to reduce fixed costs, produce a more uniform supply of lamb throughout the year, and increase profitability. There are several accelerated lambing systems.

Twice a year lambing
The most intensive form of accelerated lambing is twice a year lambing whereby a ewe would produce two lamb crops per year. Twice a year lambing has the potential to maximize lamb production, but may not be practical under most commercial situations.

Opportunistic Lambing
Opportunistic lambing is when rams are kept with the flock on a continuous basis. With the right kind of ewes, this will result in a lambing interval of less than 12 months. The problem with opportunistic lambing is you don't know when lambs are due, so the timing of vaccinations, deworming, and supplemental feeding is more difficult.

Three lamb crops in two years
The most common system of accelerated lambing is three lamb crops in two years, resulting in an average lambing interval of 8 months or 1.5 lambings per ewe per year. The 3/2 system is usually characterized by a fixed mating and lambing schedule, such as May mating/October lambing, January mating/June lambing, and September mating/February lambing (or slight variations). Up to a 40 percent increase in production has been achieved with this type of accelerated lambing system.

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The STAR© system (five lamb crops in three years)

The STAR© system was developed at Cornell University. The goal is for ewes to produce five lamb crops in three years. The calendar year is divided into five segments (the points of a star) that represent one-fifth of a year or 73 days. Two fifths of a year is 146 days, which is approximately the gestation length of a ewe.

There are five lambing periods each year. Three groups of sheep are managed separately: 1) breeding and pregnant ewes and rams; 2) lambing and lactating ewes and lambs; and 3) growing lambs (market lambs and replacements). If a ewe misses a breeding, she can still lamb three times in two years.

The STAR system is a natural system that does not use hormones or light control to achieve out-of-season breeding. It involves selecting sheep that breed during any season. The Cornell Dorset flock, which has been on the STAR system for more than 15 years, averages 1.5 lambings per ewe per year.

To be successful, accelerated lambing requires the right sheep and careful management. Ewes and rams must be capable of breeding year-round. Less seasonal breeds, such as the Dorset, Merino, Finnsheep, Barbados Blackbelly, Polypay, Katahdin, St. Croix, and Rambouillet, are best suited to accelerated lambing systems.

The economics of accelerated lambing must be carefully examined. The increased income from the sale of lambs needs to compensate for the added costs and labor inputs. In addition, accelerated lambing requires a much higher level of management.

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Shed vs. Pasture/Range Lambing

Shed lambing is when lambing occurs indoors. Pasture lambing occurs outdoors. Shed lambing the most common system of lambing. Even producers who raise their sheep predominantly on pasture or range usually bring their ewes in for lambing. However, pasture lambing is increasing in popularity due to the emphasis on more sustainable systems of livestock production that require less physical inputs, including labor.

Shed lambing
Shed lambing provides the ewe and lamb(s) protection from the elements, as well as predators. It allows for earlier lambing. The primary disadvantge to shed lambing is cost. In addition to the cost of lambing facilities, labor and feed costs are usually higher. Due to the higher cost, shed lambing is most advantageous for highly productive flocks. The shepherd has more control with a shed lambing system.

Pasture lambing
Pasture (or range) lambing is more natural and generally healthier for the ewe and her lambs. However, it must occur during periods of mild weather or lamb losses can be sustantial. Predation can also be a more significant problem where pasture lambing is practiced. Feed costs tend to be lower with pasture lambing because ewes and lambs are getting most of their nutrient requirements from pasture. Labor inputs are less because ewes are lambing on their own.


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