Have a livestock vaccination plan in hand for when a disease outbreak occurs.
Vaccination is the most effective method of controlling diseases under the following conditions:
- Where avoiding exposure to disease-causing factors is difficult or impossible.
- If the disease is carried by biting insects it is impossible to keep them totally away from the livestock.
- Where there is a rapid onset of the disease.
- Some diseases develop so fast that animals die before any sign of disease becomes evident.
- Where there is no treatment against some diseases, such as viral diseases, vaccination could be used as a preventative measure.
- Vaccination could also help to prevent animals from contracting diseases that might cause production losses or diseases, such as brucellosis, that might be transferred to people.
The best way to ensure that vaccination is done at the right time is to plan and order vaccines on a seasonal (every 4 months) basis. Even if the facility selling the vaccine is located some distance away, the purchase is an action that can be planned at least a month in advance.
- A group of farmers can also pool together to buy vaccines and then store and apply them as a group action.
- Buy from a shop that keeps the vaccines in fridges that are clean, dry and working properly.
- The temperature of the fridge should be maintained at about 4°C at all times.
- There should be a back-up generator to keep the fridge cold in the event of a power failure.
- Ensure that you receive an information leaflet along with the vaccine.
- Read the leaflet and if you don’t understand or if you are unsure about anything, consult with the supplier.
- The leaflet can be filed for your own reference.
- Check expiry dates before purchasing a vaccine.
- There should be at least three months leeway before a vaccine expires after you have purchased it.
- Never use a vaccine after the expiry date.
- Consult a veterinarian before buying a vaccine to ensure your vaccination plan is best for your animals.
TRANSPORT & STORING
- Keeping vaccines cold after purchase is the greatest challenge for small-scale farmers.
- Most vaccines have to be stored at 4°C to 8°C and should not be frozen.
- Avoid exposing vaccines to high temperatures because this will destroy them.
- Take a small cool box and ice in a sealed plastic bag with you when buying vaccines.
- Keep the vaccines in the cool box on the bag of ice and use within one day; or keep the vaccine in a fridge that’s working properly until needed.
Before use, read the package insert to ensure that you are using the vaccine correctly for the age of the animal, to check that it’s safe for pregnant animals and to find out whether there are any other precautions you need to adhere to, such as regarding the dosage and the injection site.
Clean syringes and needles should be used. Re-usable needles can be sterilised by boiling them in clean water for 15 minutes. Automatic syringes should be flushed before and after use with boiling water. Syringes and needles used for other purposes cannot be used for vaccination.
Use the correct size needles for either injecting under the skin or into the muscle. Most vaccinations are given under the skin using a short needle. Use a sterile needle when drawing vaccine from the bottle to prevent the introduction of germs into the vaccine bottle. Replace the vaccine bottle in the cool box when it is not used.
After the vaccine has been drawn up, don’t leave the syringe in direct sunlight before using it again. Use the vaccine in the syringe immediately or place it in the cool box until the next use.
In many cases a local reaction can occur at the injection site in the form of swelling that will subside within a few days. If dirty needles or syringes have been used, the injection site may become infected and the swelling can result in an abscess.
When wet animals (for example after they have been dipped or following a rainy spell) or animals with a very dirty skin are vaccinated, the germs on the skin can also be transported through the skin by the needles used or the germs can penetrate through the injection hole that remains after vaccination.
In a few cases vaccine can cause general reactions. This could include the following signs of disease: tremors (shivering), swelling of the eyelids and face, difficulty breathing and, in severe cases, the animal may collapse and experience convulsions. In such cases, a vet should be consulted.
In pregnant or lactating animals, certain vaccines can cause abortions as well as a decrease in milk production.
The following factors should be taken into account when drawing up a vaccination plan:
The best time to develop a good immunity on a herd basis is to vaccinate replacement animals before they are mated for the first time. Vaccines that can’t be used in pregnant animals can be used effectively in this age group.
Vaccinations against insect-transmitted diseases will give long term protection if they are given twice to replacement animals with an interval of six to twelve months. This immunity can then be boosted in the adult animals when there is an outbreak of a specific insect-borne disease or these vaccines can be repeated on an annual basis in adult animals when farming in a high-risk area.
Season and stage of production
- If they produce one offspring per year, cows are pregnant for 9 months and non-pregnant for 3 months.
- Ewes are pregnant for 5 months and non-pregnant for 7 months.
- Some vaccinations can’t be given to pregnant animals, for example, to prevent reproduction losses during breeding or in the pregnant animal.
- Other vaccinations must be given to the pregnant animals to boost their immunity and the immunity given to the calves through the first milk (called colostrum).
- In calves and lambs the protection obtained from the mother ends between the ages of 3 to 6 months.
- It is essential to give the first clostridial vaccinations at 3 months of age; that is the black quarter vaccine for calves and the pulpy kidney vaccine for lambs.
- Because these are inactivated vaccines and the immune system of the young animals is not fully developed yet, this vaccination must be boosted 4 weeks later by vaccinating the animals again with the same vaccine.
- The other essential vaccines that should be given to calves are the botulism and anthrax vaccines.
- Heifer calves should also be vaccinated against brucellosis at between 4 and 8 months of age.
The table below shows a visual overview of all the factors that should be kept in mind when developing a vaccination plan for adult animals and their offspring. Only the most basic vaccinations are included in this sample plan and many additional vaccinations can be added in consultation with the veterinarian who supplies you with the vaccine.
CAUSES OF FAILURE
There can be various reasons for vaccine failure. The main causes, however, can usually be related to the animal being vaccinated, the vaccine itself or the way in which the vaccine is being administered:
The animal being vaccinated
Poor condition: the level of reaction to the vaccine and immunity produced is dependent on the animal’s own body reserves and the ability to produce immune cells.
Heavy internal parasite infestations: Ongoing parasitic infestation can suppress the immune system and reduce the reaction against a vaccine.
- Damage to the vaccine during storage, such as exposure to high temperature.
- Damage to the vaccine during use, such as a drawn-up syringe left lying in the sun.
- Use of expired vaccines or vaccines that have been partially used and then stored for a long time.
- Incorrect vaccine used due to incorrect disease identification.
- Different strain of germ causing the outbreak, which is not included in the vaccine used.
- Sub-standard vaccine batch.
Also read: How vaccines work against diseases
- Wrong dose.
- Vaccinating too late when a disease outbreak has started already.
- Antibiotics used at the same time as with some live bacterial vaccines.
- Vaccinating at the wrong age.
- Vaccination booster is not given when indicated by the product information leaflet.
- Disinfectant was used to clean the syringe and needles when a live vaccine was used.
This article is an extract from the Afrivet training manual used for training farmers and farm workers in primary animal health care, was written by dr. Danie Odendaal and first appeared in Farming SA.