Clostridial and pasteurella vaccines
CLOSTRIDIAL spores are ubiquitous in the environment, being found in the soil and are also present in the animals gut.
Clostridial disease can affect sheep of all ages depending on the strain; generally the first noticeable clinical symptom is sudden death – which leaves little option for treatment.
Similarly pasteurella pneumonia is a condition that offers little opportunity for corrective action.
Its causative strains are present in healthy animals normally residing in the tonsils and only become an issue when the animal’s immune system is compromised – possibly due to stress. Vaccination is essential to reducing losses due to both these conditions.
The clostridial and pasteurella vaccines are inactivated vaccines – they won’t recreate the pathogen, and are generally more stable and available than live attenuated vaccines (such as Enzovax or Toxovax).
The clostridial vaccine is an inactive form of the various strains and is designed to elicit an immunological response where the animal’s immunological memory will kick in when it is exposed to the targeted pathogen later in life.
Administration: In all cases farmers need to follow manufactures instructions carefully in terms of product storage and correct administration.
In most cases an automatic vaccinator gun is recommended as it facilitates the process.
Most products are administered via a 1 to 2 ml dose (product dependant: read data sheet) given by subcutaneous injection in the loose skin on the upper side of the neck.
Cleanliness essential throughout the process, it is generally not recommended to conduct vaccinations on sheep with wet fleeces.
Each animal has to complete a full primary course of vaccination.
This requires two doses given four to six weeks apart (again - read manufactures instructions). This is often one of the areas that are not done is correctly at farm level. Onset of immunity will not occur until two weeks after the primary vaccination has been completed which will take 6-8 weeks from the start of the process depending on the product used.
Active immunity (i.e. in those that have received the full course) is reported to last up to 12 months. Remember a single shot is not sufficient. Once the primary vaccination has been carried out a yearly single booster vaccination 4-6 weeks prior to lambing will maintain immunity.
Passive immunity is the transfer of maternal immunity to new-born offspring that occurs via colostrum (provided that the ewe has been vaccinated four to six weeks pre lambing).
Remember sufficient amounts and quality of colostrum must be consumed within the first 24 hours.
As passive immunity declines lambs may need to be enrolled on a vaccination programme as depending on farm experiences with disease threats at this stage of life.