Animal Care

Preventative Health Management at Lamb Farms

A vaccination program provides inexpensive insurance against common sheep diseases. It is generally recommended that all sheep and lambs be vaccinated for clostridial diseases. CDT provides protection against the most common clostridial diseases: clostridium perfringins type C & D (overeating disease) and tetanus. Covexin®-8 confers protection for additional clostridial diseases. The use of Covexin®-8 and other vaccines depends upon the disease risk and diagnosis of particular diseases in the flock.

Vaccines are available for sore mouth, caseous lymphadenitis, vibrio and chlamydia abortion, epididymitis, and rabies. There is limited availability of a vaccine for footrot. Some vaccines (e.g. sore mouth, caseous lymphadenitis) should not be used unless the disease is already present on the farm because vaccination will introduce the disease to the farm. Such vaccines are advocated to reduce the incidence of disease, not prevent it in its entirely.

Anthelmintic resistance

Gastrointestinal parasites (worms) are the primary health problem affecting sheep raised in warm, moist climates or during periods of warmth and moisture. A parasite control program that integrates management practices with targeted selective deworming (using the FAMACHA© system, 5-point check©, or performance indicators) should be implemented. Regular deworming of all animals in the flock or in a management group is no longer recommended due to the widespread existence of drug-resistant worms. To slow the development of resistant worms, it is now recommended that clinically parasitized animals be given combination treatments (dewormers from different chemical classes).

Fecal egg count reduction tests should be conducted to determine which dewormers are effective on a farm. If natural products are used in the internal parasite control program, animals should be regularly monitored to see which ones require treatment with “chemical” dewormers.

Abortion

When a ewe experiences an abortion, she should be isolated from the rest of the flock. The dead fetues, placenta, and fetal tissues should be removed immediately and buried or composted. The lambing area should be disinfected. Antibiotics should be given (fed or injected) during an abortion storm to prevent further losses. Chlortetracycline is FDA-approved for this purpose. However, a written script must be obtained from a veterinarian. Including monensin (Rumensin®; Rx) or Decoquinate (Deccox®) in the feed or mineral during the last third of pregnancy may help to prevent abortions caused by toxoplasmosis.

Maintain a closed flock

The best way to maintain a healthy flock is to maintain a closed flock. Once the genetics of the ewe flock has been established, replacement females should be selected from within the flock and new acquisitions should be limited to rams. Unfortunately, artificial insemination (AI) is not a very viable option for most shepherds, making the introduction of new rams periodically necessary.

It may be possible for large flocks to select their own ram replacements, but for most shepherds, outside ram purchases are necessary to avoid unacceptable levels of inbreeding. Fortunately, rams spread fewer diseases than ewes. While rams can still introduce sore mouth, footrot, pinkeye, or caseous lymphadenitis to a flock, they are not likely to introduce vibrio or chlamydia. They are not believed to transmit scrapie, though the use of RR rams will ensure the birth of lambs that are scrapie-resistant. Epididymitis (caused by Brucella ovis) is a concern in some geographic locations.

You should not loan your ram(s) to another farm unless the health status of the flock is equivalent to yours (or better). You should not allow other producers to bring ewes (or does) to your farm for breeding unless the health status of their flock is equivalent. There are other ways to help 4-Hers and new shepherds besides making your farm and animals available to them.

Producers are encouraged to develop a written biosecurity plan and to follow it to prevent the introduction of diseases and other problems.

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 utilize 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 fieldwork 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 fewer parasite problems compared to lambs born later in the spring.

Late Lambing

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. The 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 plans for dealing with both potential problems.

Fall Lambing

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 evenly distributed, resulting in more stable prices and steadier demand.

Accelerated Lambing

Accelerated 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 fewer 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 that are poor. Keeping the ram with the flock all the time also increases the probability 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. 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.

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 disadvantage 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 substantial. 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

Lambing is usually 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.

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