Medicine storage

Responsible use of Medicines in Agriculture (RUMA) and Red Tractor® have introduced the requirement for specific training on responsible and competent medicine use in livestock to be included in their requirement protocols (RT® version 5:1 2021). One person, at least, on each farm should hold a certificate of attendance of training.

Training in the responsible and competent use of medicines has been carried out by veterinary surgeons since the conception of the profession. The Pig Veterinary Society (PVS) specifically has discussed this matter in depth for over 20 years (Carr, 1996). Adoption of good management practices by the UK pig industry has led to changes throughout the global livestock industry (Carr, personal observation).

Opportunities to provide training to clients on proper medicines use, can be encouraged by on-farm auditing systems. These opportunities need to be grasped by the profession. Not only is this good practice, but also an additional income stream. The veterinary surgeon needs to become the ‘coach’ on the farm. The veterinary surgeon is the expert in responsible and competent medicine use in livestock on the farm and this expertise needs to be effectively passed on. This paper provides our colleagues with examples the authors' practice uses to illustrate one specific area, medicine storage, as a guide to developing such a training course.

What are the major areas of concern regarding medicine storage?

Areas of medicine storage, where veterinanians should be concerned, can be illustrated by a personal study that has taken place over 20 years (Carr personal observations) (Table 1).

One author (JC) reviewed over 400 farms worldwide (90% pig farms, other 10% mix of poultry, cattle, sheep and apiaries). The data are expressed as ‘errors’ in medicine storage. While 57% of the farms had no ‘error’ recognised during the farm visit, 43% of farms had at least one error; however, at the visit there may have been more than one error and each error is counted separately. For example, the medicine store could be dirty, have no temperature recording and have medicines in the wrong place — this would be recorded as three errors. The medicine storage issues discussed below are based on the findings of this study.

Medicine security

Medicines must be placed in a secure location away from children, animals and thieves (Figure 1). The medicine stores must be in a lockable area. If medicines are in an open facility, the facility store itself must be lockable.

Medicines used around the farm must be returned to the secure medicine store or placed, under lock and key, around the farm. If medicines are removed from the medicine area, the storage requirements must be met. For example, if the oxytocin in use on the farm is required to be kept below 8°C, storing the bottle overnight in the farrowing area at 20°C is not adequate.

Medicine security must include the warm medicine storage, infeed and in-water medicine storage areas. All feed bins should be clearly numbered and their position marked on a site map (Figure 2).

When using feed medication in bags, consider colour coding the bags or the food.

Medication through water delivery systems should be designed, numbered and managed to avoid medication mistakes. The water system also needs to be secure to avoid interference from the general public or animals.

If medicine bottles become wet the label can become loose and fall off. If the label is loose, it must be securely replaced (Figure 3).

Certain products may require additional security so that if the bottle falls and breaks the products do not come into contact with human skin. Prostaglandins, would be a classical example, and they should be stored where accidental exposure does not happen, in a sealable plastic box within the medicine store. Then if there is a breakage the product is contained.

Without training it is common for farm staff to handle medicine products with insufficient care, exposing themselves to potential sharp and stick injuries (Carr et al, 2018).

Temperature control

All medicines have specific storage temperature requirements. During the routine farm veterinary audit the temperature of all medicine stores should be checked and recorded (Carr et al, 2018). The farm medicine areas (cold and warm) should have maximum/minimum thermometers, which should be monitored at least weekly, the readings recorded and action taken when there is an issue. Training in the use of a traditional maximum/minimum thermometer must also be carried out (Box 1). Digital thermometers may be easier on some units.

Box 1.A maximum/minimum thermometerThe minimum temperature is read on the left hand side — note red indicates below freezing point. The maximum temperature is read on the right hand side — black indicates above freezing point

To reset the max/min thermometer depress the central button (A) and allow the metal floats to decend to the top of the mercury/oil miscus.

There are three main medicine store areas:

• Below -20°C.
• Between 2–8°C
• Above freezing but below 30°C.

These temperature requirements have particular relevance with regard to the temperature medicine chain when medicines are moved to clients and kept in vehicles.

Frozen medicine storage -20°C

Freeze dried vaccines and autogenous vaccines may require -20°C freezer storage (Figure 4), but these are impractical as most veterinary practices have no access to suitable extremely cold refrigeration systems. Occasionally -70°C is required.

Cold medicine stores 2–8°C

Products requiring storage at 2–8°C typically include vaccines and open medicine bottles (Figure 5).

Warm medicines stores — generally less than 30°C (or other specified).

Most medicines, including injection, in-feed and water antibiotic medications, have specified requirements to be stored below 25–30°C (Figure 6). It is therefore vital to check the label.

Common faults in medicine temperature control

Cold medicine storage

Refrigerators may not be running at the correct temperature, being either too hot or too cold (Figure 7). If the vaccine products are subjected to freezing, their activity is generally significantly reduced or they may be rendered useless. Freezing could break down vaccines and potentially render the product toxic, by releasing endotoxin from whole bacterial vaccines for example.

With cold refrigerators, there is no warming element and if the room temperature drops below freezing, the temperature of the cold medicine store will eventually equilibrate with the ambient external temperature and freeze the products stored in the fridge, rendering them useless.

Warm medicine storage

Unfortunately the majority of farms do not provide any specific warm medicine store facilities. In many parts of the world, the summertime temperatures may exceed 25 to 30°C.

It is important to note that the inside of a car will also exceed these temperature limits. In transport, such as the car, medicines need to be stored appropriately.

Medicine temperature examinations

A remote temperature data logger can be utilised and the records provide excellent information on the medicine storage (Figure 8). It should be placed in the medicine storage area, and monitored for around a week, with a reading taken every 15 minutes. Placing an additional logger on the outside of the storage area provides a climate base line.

The medicine temperature report should include some simple analysis — maximum, minimum, average temperature, percentage of time above and below acceptable temperature requirements for the medicines (Figure 9).

There is a temperature variation around the refrigerator (Figure 10). During the farm health visit note how the medicines are placed in the medicine store. The main areas to check are by the ice plate, main body, bottom of fridge and door of the fridge. Note only in the body of the fridge is a temperature of 2 to 8°C maintained, in a correctly running fridge (Figure 7).

For any temperature maintenance system it is vital that air circulation is possible to allow the store temperature to be evenly distributed. In many stores, medicines are overstocked or products remain in their boxes, restricting air movement around the medicine products, leading to uneven or inadequate cooling (Figure 11) (Carr, personal observation).

It is also important that any other storage requirements for specific products are adhered to — some products may need to be kept out of the light, for example tetracycline products.

Medicine placement

A common mistake is having multiple bottles of the same medicine medicine open at one time (Figure 12), for example, stockpeople may return a medicine into the store on the wrong shelf, meaning that next time that medicine is required, a new bottle is opened by mistake. This can result in a significant increase in the costs and waste medicines.

Sometimes, stockpeople can become confused with different brands of the same medicine, which have different labels. Adequate training is required to ensure that this error does not lead to multiple bottles of the same product being open at the same time.

All products need to be recorded when they arrive on the farm. Ensure that there is a protocol in place, so that any medicines recently purchased, are placed at the back of the store. Having only a 1 month supply of medicines on the farm assists in ensuring that medicines remain in date.

Hygiene of the medicine store

It is generally disappointing that the medicine storage can be dirty (Carr, 1999). A dirty store could indicate that the stockpeople do not respect the animal medicines properly (Figure 13).

In addition to poor hygiene, the medicine store is often not respected as a chemical store. Other products, including human food products and pig products, in particular, may be found in the store area (Muirhead and Alexander, 2013). This can pose a risk of introducing novel pathogens onto the farm. The pathogen of note, is African swine fever. If frozen pork, infected with (ASF), is present in the fridge, blood from this product could contaminate the seal of medicine bottles and the farm staff will then inadvertently infect their pigs with ASF through injection.

Maintenance of the medicine store

A simple mistake made on a few farms in the author's (JC) study, was just that the cold medicine store was old and poorly maintained. This included poor temperature control because the fridge seals had worn away. On a couple of farms the authors have been astonished to find the cold medicine store door was not even closed regularly!

Medicines out of date

All medicine products used on farm must be used according to the data sheets and any labeled instructions. The age of the product, date of opening of the seal and the date of use of the product should all be recorded. Many products are sold in quantities, where the farm team cannot utilise the product within the ‘once open use by date’. Batching programmes and planning are required by the whole team to avoid misuse of medications. Out of date products are illegal to use, and any such products found must be removed from the farm.

Illegal medicines

While many medicines may have a role to play in the improvement of a specific animal's welfare, there are restrictions on use. These restrictions on use may extend to an actual ban on their use in livestock, for example metronidazole. Please refer to the PVS Prescribing Principles for Antimicrobials (PVS, 2020) and the prescribing cascade (Veterinary Medicines Directorate, 2021) for up to date advice on medicines applicable for use in pig production.

Conclusion

Veterinary care for medicines used on farm is a priority. The farm health team must receive specific training in how to manage and dispose of the medicines.

KEY POINTS

• Medicines are vital to pig health and welfare.
• Medicines need to be stored, managed and disposed of properly.
• The veterinarian can be the ideal on-farm coach to ensure excellence in medicine storage.
• Medicine storage auditing should be carried out in each farm visit
• Medicines all have specific temperature storage requirements.
• Medicine data sheet requirements must be adhered to
• Medicines need to be kept out of the reach of children and animals
• Medicines are administered by injection, feed and water and all have their own specific requirements.