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Snuggled in the corner
Winter-born lambs

Loafing area
Drop pen 

Winter lambing
Winter lambing

 January lambs
January-born lambs

Shed lambing
Shed lambing

 Creep feeding
Early lambs are usually creep-fed

March lambs
Born in March

Born on pasture
Lambing on pasture

Range lambing
Range lambing

Ewes and lambs
Ewes and lambs in dry lot

 One too many
Spring lambs


Lambing systems

A lambing system concerns 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 lambs. Producers need to match the lambing system to their goals and objectives, resources, and market demand. The same farm or ranch may utliize different lambing systems for different groups of sheep.

Early vs. Late Lambing

The first decision to make is when to lamb. There are pros and cons 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 who farm full-time, the winter may be 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, which frees labor for other farming operations.

Another advantage is marketing. Historically, lamb prices have been highest during the first half of the year, especially during the Easter season. As a result, lambs born in the winter were usually sold for higher prices than those born in the spring. In more recent years, population demographics have altered the demand for lamb. Very often, the highest lamb prices of the year occur slightly before the Muslim Festival of the Sacrifice. This holiday moves 11 days forward each year.

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.

If lambing occurs during the winter months, good facilities are needed. Housing is a big consideration. Overhead costs are higher with winter lambing . Mastitis, scours, and pneumonia can 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. If winter-born lambs are put to pasture, they usually have less parasite problems compared to lambs born later in the spring.

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. 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. Most ewes conceive during their first heat cycle and almost all 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, as most predator species have pups or kits to feed. It is essential that producers have a plans for dealing with both potential problems.

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, around Christmas time.

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 would be more even distributed, resulting in more stable prices and steadier demand.

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. Twice a year lambing is probably most common near the equator.

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. Lambs may also be born forage resources are poor. Keeping the ram with the flock all the time also increases the probablity of inbreeding, if female progeny are not removed in a timely fashion.

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). Another option is an 8 month overlapping system in which two groups of ewes lamb every eight months, but there are six lambing periods per year.

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

The STAR© system was developed at Cornell University. The STAR© system is designed so that ewes 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, Romanov, 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.

Shed vs. Pasture/Range Lambing

Shed lambing is when lambing occurs indoors. Pasture lambing occurs outdoors. Shed lambing is 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 becoming more popular. It 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.

Range lambing

Range lambing does not usuallly begin until mid-May when the risk of inclement weather has passed. Lambing is usualy unassisted. Lambs are marked (docked and castrated) all at once, usually before they are 60 days of age. Lambing occurs in pastures that are close to the homestead. Sometimes, the first-time lambers in range flocks are shed lambed.


Late updated 19-Apr-2021 by Susan Schoenian.
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