Vaccination for the Smaller Pig Population Part 2

Editorial Information

Part 2 - Vaccine Handling and Application

Storage and Use

All vaccines used in pigs have a finite shelf life and as biological products are susceptible to degeneration. Storage is normally required under refrigeration - without freezing - and in the dark. Never use products that are out of date or have not been stored correctly. Keep the refrigerator under lock and key and keep vaccines away from children.

One issue particularly relevant to the smaller producer is part used bottles. Most products are produced for use in larger populations and bottles will often contain 25 -50 doses per bottle and most will contain the recommendation of "if not used within 24 hours opened bottles should be discarded". This is highly wasteful and advice should be sought from the supplying veterinary surgeon as to how to deal with such requirements safely and economically. In some situations, with the appropriate veterinary oversight it is possible to use a bottle of vaccine across a number of populations ie sharing product but great care is needed to avoid risks of disease spread. As an absolute minimum a clean needle and syringe is needed at each premises.

Administration

Each specific vaccine has a specific dose rate and administration protocol that must be followed if the vaccine is to be effective. The range of vaccines used in the herd will affect protocols but for the most important vaccines for the smaller producer, the following guidelines are applicable.

E.coli/Clostridial disease- combined vaccines exist (eg Porcilis 6C : Intervet Schering Plough, Gletvax6 : Zoetis) designed to be administered to the gilt/sow prior to farrowing with protection passed on to the piglets via colostrum. Two 5ml doses are required as a primary course with a specified interval between the two doses, the second dose given up to two weeks prior to farrowing. In subsequent parities a single booster dose is required two weeks prior to farrowing. (NB - sheep can be a reservoir for clostridial infection.) E.coli only vaccines also exist and require the same protocols for administration. However due to the more extensive husbandry that tends to apply in small herds the combination products are advisable. (NB - sheep can be a reservoir for clostridial infection and when kept with pigs the disease risk for both can be higher. Both species should be vaccinated with appropriate vaccines)

Figure 1: Typical neonatal E coli diarrhoeaErysipelas - Breeding animals should always be vaccinated for Erysipelas with a two dose primary course e.g. in the gilt, with booster doses given every parity (i.e. at five to six monthly intervals). Maximum benefit can be derived by giving sow vaccine in late pregnancy up to two weeks before farrowing. Don't forget boars. Growing pigs, where necessary, can be vaccinated from six weeks of age. In high-risk situations a two-dose course (with a four week interval) is necessary.

Figure 2: Diamond lesions on the back of growing pigs are typical of Erysipelas

Erysipelas vaccine is also available in combination with Parvovirus vaccine for use in breeding animals. This combination can be used as one of the two primary doses for young gilts pre-mating and if necessary as the booster dose annually. (NB - turkeys and sheep are also susceptible to Erysipelas and their presence within a mixed farming operation may increase the risk of disease in all of these species.)

<pstyle="text-align: justify;">PCVAD - Disease caused by Circovirus Type II can cause devastating losses in any size population and is controllable by vaccination. Two possible protocols are available:

Sow vaccine (Circovac : Merial). Similarly to E.coli/Clostridial vaccines, this is administered to breeding animals prior to farrowing to protect the young piglets via colostrum. Two doses with an interval of three to four weeks are needed, with the second dose two weeks prior to farrowing. (Gilts may also be vaccinated prior to service.) Single booster doses are required at least two weeks prior to each subsequent farrowing.

It should be noted that this vaccine comes in two parts which must be reconstituted and used within three hours.

Piglet vaccine (Circoflex : Boehringer; Porcilis PCV : MSD Animal Health Suvaxyn PCV : Zoetis) To protect the growing pig it is generally most effective to apply vaccine directly to them rather than relying on sow vaccine along. These are single dose vaccines given to young piglets from two to three weeks of age (The age of administration and physical dose required depends on the product) that protects growing pigs for four to five months (i.e. to slaughter weight). (In high challenge situations, two doses of one product (Porcilis PCV) are indicated but this is unlikely to be necessary in small populations.)

Figure 3: PMWS in a weaner can be effectively prevented by vaccination.

Fig 4: PCV vaccines are now available for both sows and piglets

Some vaccines are available as specific combinations (e.g. Erysipelas/Parvovirus) but it can be seen from the above that in some cases uncombined vaccines may be required at similar times. As a general rule, NEVER mix vaccines (unless specifically recommended) and do not apply simultaneously. This can be challenging if young piglets require several different vaccines and advice should be sought form the veterinary surgeon.

Needles and syringes

Needles and syringes used must be clean and free from disinfectant or alcohol. A new disposable needle and syringe should preferably be used each time a bottle is used.

Most vaccines are given by intramuscular injection and the following needle sizes are recommended:

a. Young piglets up to five weeks of age: 21G x 15mm

b. Gilts: 18G x 25mm

c. Sows and boars: 18G x 40mm

(In rare cases, wider gauge needles may be necessary for "thicker" vaccines.)

In general, always inject pigs in the neck.

Adverse reactions

Occasionally pigs will suffer an adverse reaction to a vaccine. This can be the result of:

• Cold shock - especially in young piglets if given straight out of the fridge. Always warm to body temperature before administration.
• Accidental injection into an artery or vein. (In both cases the reaction is instant and normally temporary, with recovery in 10-15 minutes.)
• Allergic reaction. Very rarely this will occur after multiple vaccinations, within one hour of application. These reactions can sometimes be fatal.
• Abortion. With modern vaccines licensed for use in pregnant animals (e.g. E.coli, Erysipelas, PCV) abortion is rare. Previous contamination of a part-used bottle is often to blame.
• Others. Rarely young piglets will react to the other chemicals included in vaccines (adjuvants) and may vomit and collapse. Death is a rare consequence.

In addition to reactions in pigs, operators must be aware of the dangers of self-injection. The oil rich vaccines of the past have largely been replaced with modern adjuvants, but there is still a risk of tissue damage if self- injected. Where such accidents occur, urgent medical attention should be sought (preferably Hospital Accident and Emergency) and you should take the data sheet (SPC) of the product with you.

Disposal of bottles etc.

All pharmaceutical products, needles and syringes must be safely disposed of. On no account should they be discarded in ordinary domestic waste. The most practical solution is to purchase a "sharps bin" from your veterinary surgeon who will dispose of it by incineration when full.

Recording

There is a requirement to record all medicines used in food producing animals including vaccines. The date given, identity of animal, product, batch number and expiry date, dose and withdrawal period (indicating the earliest possible date for slaughter) should all be recorded. All vaccines currently licenced in the UK have zero meat withdrawal periods ie there is no required time delay between administration and sending a pig for slaughter. Such records should be kept for 5 years

Further information

Further detailed information of vaccines and their use in pigs can be found in:

• RUMA - Responsible Use of vaccines and Medication in Pigs available at http://www.ruma.org.uk/guidelines/vaccines/long/pig%20vaccine%20long.pdf