Vaccination is an immunization process using biological agents to induce protective effect against known disease agents in animals in order to prevent disease occurrence in the induced animals.

However, the administration of these biologicals varies from oral to parenteral methods as well from one livestock species to another. The purpose of a vaccination is to provide exposure to a non-virulent (non-infective) form of a disease agent before the animal is exposed to a natural infection.

This vaccination causes the animal to develop antibodies and cellular resistance that protect against disease or infection.

Note that vaccination is not a simple process that automatically produces immunity. You will get to know the principles involved in inducing immunity in animals in the course of your practical year program.

Ensure to also adhere to the following guidelines;

Keep vaccines refrigerated (not frozen).

Keep vaccine out of direct sunlight.

Be sure to use vaccines before expiration date.

Vaccinate healthy animals; avoid vaccination of stressed livestock animals.

Follow all label directions on proper routes of administration.

Follow all label directions for vaccination of pregnant animals, and observe age of animals at vaccination.

Ensure that booster injections are given as at when due if indicated on the label directions.

Avoid stress of newly vaccinated animals.

Principle of Animal Immunity in Disease Control

1. The Immune System

The function of the immune system of the animal is to protect the body against pathogenic agents. The immune of the animal is innate and is composed of two parts, humoral and cellular.

The humoral part produces substances like antibodies found in the blood. These substances are able to prevent growth and development of pathogens or make them stick together to facilitate their removal from the body.

The cellular part produces cells (like T-lymphocytes, Natural Killer cells) that ingest and destroy pathogens. Both the humoral and cellular immunity are not directed against particular pathogens and therefore are said to be non- specific.

Types of Immunity

Immunity can be classed as either natural or acquired. Natural immunity is an innate or inborn ability to resist certain types of diseases and this immunity does not involve production of antibodies.

Acquired immunity on the other hand is immunity that animal develops to resist specific infectious agents either passively or actively.

Passive immunity involves the transfer of pre-formed antibodies from an immune animal to a susceptible animal to provide protection against a pathogen as obtained when a calf suckles the dam soon after calving or by injection of antiserum into another animal.

This type of immunity last for a short period. Active immunity is obtained when animal develops antibodies following exposure to an infectious agent or pathogen either natural infection or by vaccination. This type of immunity last longer in the animal.

2. Vaccine Failure

Vaccines can fail for a variety of reasons which include:

Failure of the animal to respond. A certain percentage of animals will not respond and build an immune response to a vaccination. This is more likely in stressed or debilitated animals.

Insufficient resistance if the animal is faced with overwhelming exposure.

For younger animals there are blocking maternal antibodies (from colostrum) present that interfere with the ability of the animal to build immunity. This is the result of vaccinating animals that are too young.

There is a lag time of up to three to four weeks before sufficient immunity can develop in a properly vaccinated animal.

A booster dose is not given to generate an adequate immune response. This is applicable on vaccines with label recommendations that specifically recommend a booster.

Improper handling of the vaccine such as, exposing to sunlight, improper storage temperature or mixing problems. This is the most common cause of vaccine failure.

Note: You can minimize the chance of vaccine failure by carefully handling and administering the product.

Diseases to Be Vaccinated Against in Some Livestock Animals

1. Beef

Vaccines recommended as essential for these common diseases.

The vaccines for clostridialdiseases are available in various combinations from two to eight agents.

These diseases are common and usually cause sudden death with little time for treatment. Because treatment success is rare, emphasis is properly placed on preventative measures.

IBR (Infectious Bovine Rhinotracheitis): Also known as rednose. It causes inflammation of the upper respiratory tract.

PI3,(Parainfluenza Type 3). Upper respiratory infection, suppresses the animal’s immune system, allowing other diseases to develop.

BVD, (Bovine Virus Diarrhea). A complicated disease, it can result in a wide variety of disease problems from very mild to very severe

Brucellosis. Vaccination MUST be provided by accredited veterinarian and the heifer must be of a specific age. Vaccination for Brucellosis is highly recommended for cattle that may be involved in interstate movement (such as shows or fairs) or animals that may be marketed interstate.

Other diseases less vaccinated against include:

Leptospirosis: Bacterial infection that typically causes abortion in last half of gestation or still birth.

Pasteurella: Commonly causes pneumonia.

Hemophilus: Has the capacity to attack many different organs in the body interrupting blood flow.

Vaccination Programs for Different Classes of Livestock and Other Preventive Measures

Vibriosis: A bacterial disease transmitted through natural breeding. It may result in infertility and abortion.

2. Sheep and Goats

It is recommended as essential to vaccinate sheep and goats for two main diseases:

Tetanus(lockjaw) caused by Clostridium tetani.

Enterotoxemia(overeating disease) caused by Clostridium perfringens types C and D.

3. Swine

It is expected to vaccinate against the following swine diseases.

African Swine Fever(ASF) is a major infectious disease of swine caused by African swine virus producing signs such as loss of appetite, pigs hurdling together, small purplish blotches on the skin, in coordination and laboured breathing which often result to death.

Atrophic rhinitis is a bacterial disease that causes inflammation of tissue inside the nose. Nasal passages damaged are not effective filtering the air the pig breathes, allowing more bacteria access to the lungs. (For use in young pigs if the disease is known to be present in the herd).

Erysipelas is an infectious swine disease that can cause fever, sudden death, diamond shaped skin lesions, stiffness, and abortion. (A good practice in all pigs).

Parvovirusis a reproductive disease that may result in embryonic deaths, mummified fetuses and stillborn pigs. (Breeding animals only).

Often, even more important than the vaccination program for swine is good animal care. It is important to keep pigs either on a frequently cleaned concrete pen or new dirt pens that have not previously had pigs on them.

Keeping pigs on the same dirt on a long term basis is not advised for proper care of swine. Vaccination programs are an important part of successfully raising livestock. There are many different products available for use.

Consider all factors in selecting what products to use. Consulting with a veterinarian is a good way to help establish a personalized vaccination program for the species and area.

General Prevention Measures

Preventing diseases entering and spreading in livestock populations is the most efficient and cost-effective way of managing disease.

While many approaches to management are disease specific, improved regulation of movements of livestock can provide broader protection.

A standard disease prevention programme that can apply in all contexts does not exist. But there are some basic principles that should always be observed.

The following practices aid in disease prevention:

Elaboration of an animal health programme.

Select a well-known, reliable source from which to purchase animals, one that can supply healthy stock, inherently vigorous and developed for a specific purpose. New animals should be monitored for disease before being introduced into the main flock.

Good hygiene including clean water and feed supplies.

Precise vaccination schedule for each herd or flock.

Observe animals frequently for signs of disease, and if a disease problem develops, obtain an early, reliable diagnosis and apply the best treatment, control, and eradication measures for that specific disease.

Dispose of all dead animals by burning, deep burying, or disposal pit.

Maintain good records relative to flock or herd health. These should include vaccination history, disease problems and medication.

Surveillance and Control Measures

Disease surveillance allows the identification of new infections and changes to existing ones. This involves disease reporting and specimen submission by livestock owners, village veterinary staff, district and provincial veterinary officers.

The method used to combat a disease outbreak depends on the severity of the outbreak. In the event of a disease outbreak the precise location of all livestock is essential for effective measures to control and eradicate contagious viruses.

Restrictions on animal movements may be required as well as quarantine and, in extreme cases, slaughter.

Control of Disease Outbreak

Control of disease outbreak is simplified by observing the following recommendations:

Segregation of sick animals.

Change of pastures.

Vaccination of healthy animals.

Proper disposal of litter material by burning.

Bury/burn infected carcass for proper disposal.

Clean and disinfection of premises-contaminated by diseased animals.

Consult qualified veterinarian for diagnosis.

Do not rely on untrained persons for the diagnosis of diseases.

Prompt report to district livestock authorities about the outbreak.

Quarantine.

While waiting for the diagnosis, put a disinfectant in the drinking water to prevent transmission of germs through water.

Use only proper approved methods of sanitation and treatments.

Make regular use of foot bath for animals and employees.

In summary, livestock are susceptible to a variety of diseases. One key to keeping livestock healthy is by implementing a proper vaccination program.

Having a valid veterinary-client-patient relationship is a key first step to understanding what is involved in developing a vaccination program and in getting guidance if an animal becomes ill. Veterinarians can provide useful advice in dealing with specific production practices.