Vaccinations are an integral part of a flock health management program. They provide cheap insurance against diseases that commonly affect sheep and goats.
Probably, the only universally recommended vaccine for sheep and goats is CDT. CDT toxoid provides three-way protection against enterotoxemia (overeating disease) caused byClostridium perfringins types C and D and tetanus (lockjaw) caused by Clostridium tetani. Seven and 8-way combination vaccines for additional clostridial diseases such as blackleg and malignant edema are available, but generally not necessary for small ruminants.
Enterotoxemia type C, also called hemorrhagic enteritis or “bloody scours,” mostly affects lambs and kids during their first few weeks of life, causing a bloody infection of the small intestine. It is oftenrelated to indigestion and is predisposed by a change in feed, such as beginning creep feeding or a sudden increase in milk supply.
Enterotoxemia type D, also called “pulpy kidney disease,” usually affects lambs and kids over one month of age, generally the largest, fastest growing lambs/kids in the flock. It is precipitated by a sudden change in feed that causes the organism, which is already present in the young animal’s gut to proliferate, resulting in a toxic reaction. Type D is most commonly observed in animals that are consuming high concentrate diets, but can also occur in lambs/kids nursing heavy milking dams.
To confer passive immunity to lambs and kids through the colostrum, ewes and does should be vaccinated 2 to 4 weeks prior to parturition. Females giving birth for the first time should be vaccinated twice in late pregnancy, about four weeks apart.
Maternal antibodies will protect lambs and kids for about two months, if offspring have ingested adequate colostrum. Lambs/kids should receive their first CDT vaccination when they are 6 to 8 weeks old, followed by a booster 2 to 4 weeks later. If pastured animals are later placed in a feed lot for concentrate feeding, producers should consider re-vaccinating them for enterotoxemia type D.
Lambs and kids whose dams were not vaccinated for C and D can be vaccinated with some success at two to three days of age and again in two weeks. However, later vaccinations will be more successful since colostral antibodies interfere with vaccinations at very young ages.
A better alternative may be to vaccinate offspring from non-vaccinated dams at 1 to 3 weeks, with a booster 3 to 4 weeks later. Anti-toxins can provide immediate short-term immunity if dams were not vaccinated or in the event of disease outbreak or vaccine failure. Lambs and kids whose dams were not vaccinated for tetanus should be given the tetanus anti-toxin at the time of docking, castrating, and disbudding, especially if elastrator bands are used. Rams and bucks should be boostered annually with CDT.
In addition to CDT, there are other vaccines that sheep and goat producers may include in the flock vaccination program, depending upon the health status of their flock and the diseases prevalent in their area.
There is a vaccine for sore mouth (contagious ecthyma, orf), a viral skin disease commonly affecting sheep and goats. It is a live vaccine that causes sore mouth lesions at a location (on the animal) and time of the producer’s choosing. Ewes should be vaccinated well in advance of lambing. To use the vaccine, a woolless area on the animal is scarified, and the re-hydrated vaccine is applied to the spot with a brush or similar applicator. Ewes can be vaccinated inside the ear or under the tail. Lambs can be vaccinated inside the thigh.
Because the sore mouth vaccine is a “live” vaccine and sore mouth is highly contagious to humans, care must be taken when applying the vaccine. Gloves should be used. Flocks which are free from sore mouth should probably not vaccinate because the vaccine will introduce the virus to the
Vaccinations for sheep and goats
flock/premises. Once soremouth vaccination is begun, it should be continued yearly.
Foot rot is one of the most common diseases in the sheep and goat industry. It causes considerable economic loss due to the costs associated with treating it and the premature culling of affected animals. There are two vaccines for foot rot in sheep. Neither product prevents the disease from occurring, but when used in conjunction with other management practices such as selection/culling, regular foot trimming, foot soaking/bathing, etc., can help reduce infection levels. Foot rot vaccines should be administered every 3 to 6 months and especially prior to anticipated outbreaks of hoof problems (i.e. prior to the wet/rainy season).
There is a vaccine for caseous lymphadenitis (CLA, cheesy gland, abscesses) in sheep. CLA affects primarily the lymphatic system and results in the formation of abscesses in the lymph nodes. It is highly contagious. When it affects the internal organs, it becomes in a chronic wasting disease. The cost of CLA to the sheep and goat industry is probably grossly underestimated. The CLA vaccine is convenient to use because it is combined with CD-T. The CLA vaccine should only be used in flocks which do not already show signs of CLA infection.
Abortion is when a female loses her offspring during pregnancy or gives birth to weak or deformed babies. There are vaccines (individual and combination) for several of the agents that cause abortion in sheep: enzootic (EAE,Chlamydia spp.) and vibriosis (Campylobacter fetus). Abortion vaccines should be administered prior to breeding.
Risk factors for abortion include an open flock and a history of abortions in the flock. Unfortunately, there is no vaccine (available in the U.S.) for toxoplasmosis, another common cause of abortion in sheep. Since the disease-causing organism is carried by domestic cats, the best protection is to control the farm’s cat population by spaying/neutering and keeping cats from contaminating feed sources.
Though the risk to sheep and goats is usually minimal, rabies vaccination may be considered if the flock is located in a rabies-infected area and livestock have access to wooded areas or areas frequented by raccoons, skunks, foxes, or other known carriers of rabies. Frequent interaction with livestock may be another reason to consider vaccianting.
The cost of the rabies vaccine relative to the value of the animals should be considered as well. The large animal rabies vaccine is approved for use in sheep. No rabies vaccine is currently licensed for goats. All dogs and cats on the farm should be routinely vaccinated for rabies. Producers should consult their veterinarian regarding rabies vaccination.
In order for vaccination programs to be successful, label directions must be carefully followed and vaccines need to be stored, handled, and administered properly. Only healthy livestock should be vaccinated. It is also important to note that vaccines have limitations and that the immunity imparted by vaccines can sometimes by inadequate or overwhelmed by disease challenge.
With the increasing role of small ruminants in small farms and sustainable farming systems and the rapid growth of the meat goat industry, hopefully animal health companies will develop and license more vaccines for sheep and especially goats. Scientists are currently working on vaccines to protect small ruminants against worms.
About the Author
Susan Schoenian is the Sheep & Goat Specialist at the University of Maryland’s Western Maryland Research & Education Center in Keedysville, Maryland. She has been with University of Maryland Extension since 1988. Susan began her extension career as an agricultural extension agent (“county agent”) in Wicomico County, Maryland. She also served as a Farm Management Specialist for Maryland’s nine Eastern Shore counties. In addition, she operates the following websites: Sheep 101, Sheep 201 and Maryland Small Ruminant Page, and Wormx.