Vaccines are an important part of a sheep owner’s fight against disease – but handled incorrectly they can become ineffective, or cause infection. Many illnesses found in sheep for which vaccines are currently widely available include those for commercial flocks, smallholders, or pet sheep. The most effective vaccines used in sheep are against Clostridia and Pasteurella, these may be given separately or more commonly are given in combination.

Clostridial Disease and vaccination

There are a wide number of clostridial diseases that affect sheep. These are a serious threat to those sheep which are yet to be vaccinated. These diseases can sadly cause death in as little as a few hours.

The most common types of diseases found in sheep are tetanus, lamb dysentery, blackleg, black disease, pulpy kidney, struck and braxy.

All sheep should be vaccinated for tetanus and two types of enterotoxaemia. In most cases, this is given as a combined vaccine. This vaccine should be given to pregnant ewes four weeks before lambing and supplies the protective antibodies which the new born lamb will obtain by the colostrum. 

Lambs should also receive the vaccine at 6-8 weeks of age, followed by a booster 4 weeks later and finally, at the time of weaning. 

Pasteurellosis and vaccination 

Pasteurella is a respiratory pathogen that causes health problems in all ages of sheep. Problems range from septicaemia in lambs, mastitis in ewes and pneumonia in older sheep. 

Pneumonia in older sheep can occur outdoors but cases have been shown to be more frequent in sheep which are kept indoors. This can be due to the following:

  • Poor ventilation resulting in a build-up of noxious gases in manure.
  • Higher levels of humidity.
  • Dust.
  • Accumulation of pathogens because of high stocking-density.
  • Close contact leading to the easy spread of pathogens. 
  • Stress can occur due to overcrowding.

When pneumonia does happen in sheep, it usually occurs not only because of several of the factors mentioned above, but because there could be more than one microorganism causing the pneumonia.

Mixed Pathogens 

Pathogens (disease-causing microbes) in sheep are frequently found in combination. It is probable that damage by one organism may facilitate infection by another. Subsequently, it can be difficult to figure out which pathogen is causing the problem.

Vaccination in breeding ewes is recommended with a primary course of 2 injections, 4 to 6 weeks apart followed by an annual booster 4 to 6 weeks before lambing. Lambs are given 2 doses of the vaccine from as early as 10-days of age.

Combined vaccines

There are now several combination vaccines which provide protection against Pasteurella and a range of Clostridia. These are probably the most widely used and should be considered essential to keeping your flock healthy in most situations. They are the “core vaccines” for the species, like parvo and distemper in dogs or panleukopenia in cats.

Foot Rot and vaccination 

Footrot is an extremely painful disease in sheep. It causes affected sheep to graze on their knees and rapidly lose weight. Footrot results in the foot becoming inflamed and smelly, so prevention is often better than cure. 

Footrot is also known as foot scald and mainly occurs in wet areas. Sheep should be vaccinated every 3-6 months and should always be vaccinated in spring, before a rainy season.

Vaccination alone will not stop footrot, but it is a useful tool. Other ways in which footrot can be prevented is to improve drainage, restricting access to boggy areas, foot-trimming and foot bathing.

Orf (Contagious Pustular Dermatitis) and vaccination 

Orf is a skin disease affecting sheep (and goats). It shows as scabs and sores around the hoof junction and mouth of the sheep. This means that infected lambs are therefore unable to suckle due to the discomfort of the scabs on their mouths. They do not thrive, so ewes should be vaccinated well before lambing begins. 

Unfortunately, should infected lambs manage to suck, there is a significant increase in the spread of the disease to the ewes’ teats. This can cause considerable pain and discomfort for the ewe, and she may push the lamb away as it tries to feed. Orf is a zoonotic disease (can spread to humans), so great care must be taken when managing infected sheep with orf.

Orf vaccination is a live vaccine which should be used 6 weeks before the expected occurrence of disease. It is administered by scratching the skin (scarification). The vaccine should only be used on farms and smallholdings where infection is present.

Where no orf is present, using the vaccine can reduce the risk of introducing it to the farm/smallholding. 

Abortion and vaccination 

Sadly, lambs can be lost at any stage of pregnancy, but it is normally the problems encountered at the latter stages of pregnancy which are most common, such as abortions and stillbirths.

Common cause of abortions is shown to be caused by infection; or the sheep may have had a period of stress.

There are numerous infectious agents involved in abortion. These include Campylobacter, Chlamydia and Toxoplasma, with the last two being prevented by vaccinations. If a farm or smallholding is having problems with abortion, then they must isolate affected ewes and have good hygiene protocols in place to limit the spread of disease. 

Top tips:

  • Draw up a health plan with your vet.
  • Always read the label, even if you have used the product previously, as instructions, particularly withdrawal periods, can change.
  • Follow the instructions.
  • Store in a locked container at the recommended temperature.
  • Record the use of all medicines and vaccines.
  • Check the expiry date and discard open vaccine vials after 24 hours.

If you have any concerns in regards to the sheep vaccination, always consult a veterinary surgeon or SQP.

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