SESSION 2 A. Management of animal health
Abstract
It is a fundamental requirement of good dairy farming practice that milk is produced by healthy animals. This ensures the safety and suitability of the milk and helps to maximise the viability of the dairy farm. All dairy farmers are recommended to practice an active animal health control programme that starts with biosecurity to prevent the entry of disease to the farm. All animals must be identifiable by an unique system so that they can be reliably checked for disease then treated appropriately. Proper records must be kept of the use of drugs and the status of all animals especially when treated with drugs. Drugs must only be used according to label and professional advice. The whole animal health programme is best achieved by staff properly trained and following defined procedures for all routine tasks.
INTRODUCTION
The Task Force (TF), a working group involving the International Dairy Federation and the Food and Agricultural Organization of the United Nations, comprised representatives of 20 countries representing all continents. The group worked with the guiding objective for good dairy farming practice that ‘milk should be produced on-farm from healthy animals under generally accepted conditions’. The Guidelines were developed to give general recommendations to dairy farmers but not to substitute for national legislation. They are generic by design to have the broadest applicability. Hence they apply to those farming one or ten thousand cows, to those producing milk simply to feed their family and those seeking to supply large markets, to those with traditional common herds and those with intensive closed units, and to be understandable and achievable by all.
The TF agreed that animal health has specific basic tenets
- only healthy animals produce efficiently
- only healthy animals produce entirely safe and suitable products for human consumption
- only healthy animals contribute to profitable dairying.
Dairy farming must be profitable to sustain farm income. Rural development and reliable earnings require the maximal efficient output possible and for this, need the best and most widespread animal health achievable. However, to achieve a high health status throughout the herd and to maintain a healthy herd requires an understanding of the hazards affecting health, assessments of relative risk and appropriate strategies to achieve best health. The people undertaking the management of dairy animals and supervising the milking operations must be suitably skilled. This requires basic knowledge, training and appropriate practical support. It is central to good dairy farming practice that herd health is achieved and maintained by a preventive herd health programme.
KEEP ANIMALS HEALTHY (minimise the amount of infection and disease)
Prevent entry of disease on to the farm
Disease endemic to any individual farm will be known to some extent by the farmer and the default management will exert some measure of control. Although the prevalence of infection will vary with the quality of management practiced the herd is always vulnerable to novel diseases and new strains of common disease pathogens so the first requirement of herd health control is a ‘biosecurity programme’. This requires that farmers should only buy animals of known disease status where this is possible and then should control the introduction of new animals on to the farm. Some level of pre-purchase screening of animals is usually possible. When animals are bought through a market then a declaration of health may be made by the vendor. Animals should only be bought that are identifiable and accompanied by valid certification e.g. records of vaccinations and recent treatments. For the majority of farms some quarantine of new animals is possible and highly desirable. Moving animals may be part of the risk and so the vector potential of transport visiting the farm is understood and managed.
Good practice is usually to maintain the herd separately from that of neighbours by secure fencing and boundaries. With many herds this is also necessary to retain cows for management including milking and efficient feeding of the animals. However, some cultural systems rely on common grazing either of young stock or of all animals. This may be necessary because of common rights to grazing or in the interests of efficiency when owners possess few animals and the herd is a community concept. Application of good practice has to be pragmatic such that the definition of the herd is the key factor. A logical extension to securing the herd is to restrict access to potential vectors, most risky being other people and various wildlife species. The ubiquitous role of wildlife as reservoirs of infection such as tuberculosis is an easy example of the potential problem to be prevented. A further extension is to control vermin, again ready sources of many infectious disease and parasites.
Finally, the value of hygienic management of equipment such as the milking cluster is well understood on the dairy farm. Sharing equipment especially on a casual or emergency basis must receive the same degree of consideration.
Have an effective herd health management programme in place.
The day-to-day animal carer usually has an intimate knowledge of each individual animal, easy for very small groups and impressive with herds of one hundred animals or more. It becomes much more difficult to know each individual animal in very large groups when also the relationship between animals and the carer is more distant. Occasional milkers, and other people involved in the care of the animals, may not know even a very few animals. It is essential that an identification system is in use that allows all animals to be identified individually from birth to death. Many carers will still use, or recall the times when each animal had a name that personalised dairy farming. Increasingly the need to identify animals for regulatory reasons as well as management requires accurate identification. No system is fullproof so a back-up system may also need to be in place.
Every dairy farm needs a herd health programme that specifies the preventive actions necessary to prevent new infection and deal with existing inadequacies in animal health. Such a programme will include national and regional requirements, and partly the needs of the milk buyer and local cultural conditions.
A herd health programme should aim to use the best available preventive methods. Vaccination is preferred when available and cost effective. However, prophylactic methods using chemicals such as insecticides and anthelminthics, and veterinary drugs such as antimicrobials may be the only strategy available. The efficacy and cost-benefit should be considered along with product and people safety.
Effective herd health requires the existing health of individual animals to be known as fully a possible. Then changes can be determined, but only if frequent inspection and monitoring are undertaken to ascertain changes. Specific problems are best determined under the most appropriate conditions, e.g. lameness when the animals walk, mastitis when the animals are milked and enteritis when the animals defaecate.
Animals that show obvious sickness have compromised welfare; they are sub optimal producers and a major risk to the health of the rest of the herd. On all grounds they require appropriate and effective medical treatment that may extend to euthanasia. Animals under treatment will usually produce milk unsuitable for consumption by man or any other animal on the farm. Both infected animals and the milk from infected animals, and those under treatment may need to be separated to minimise transmission of infection and danger of contaminating the wholesome milk being produced on the farm. To ensure full compliance with these obligations the treatments applied should be recorded for each animal. These should be written records to allow proper traceability, to ensure safe and suitable milk and to allow all involved in managing the animals to act properly.
In limited occasions the pathogens causing the animal infections may be zoonotic, transmissible to man, so these require even more dedication to safeguard all people in contact with the animals and milk.
Use all chemical and veterinary medicines as prescribed.
In most countries chemicals for application to food animals and veterinary medicine are available with controls on their supply. It is important only to use products in milk-producing animals that are intended for milk-producing animals.
At the simplest, product labels are supplied giving directions on use, suitability, treatment schedules (dose rates and frequencies) and effects on the animals and milk supply. Veterinary medicines are more closely controlled, often available only by prescription and usually with individual instructions for use from the veterinarian who supplies or prescribes. Instructions providing for safe and effective use of these active products are the results of scientific study and clear evidence to ensure effectiveness and safety. Use of all products is best following expert advice and a veterinary prescription or other written authority with full instructions should be obtained. Following instructions is extremely important for the animals being treated and ensuring a complete milk withhold period is essential to safeguard all the milk to be used.
Both chemicals and veterinary medicines are expensive and potentially dangerous to uninformed people and the environment so they need to be stored securely. They also need to be stored appropriately, as instructed, because their durability and effectiveness may be substantially compromised if handled improperly.
Train people appropriately.
Good animal management requires effective measures applied properly and consistently. The risk of problems increases with variables such as time, the number of people involved and the frequency of the use of any application. These can all be minimised as contributory variables by having procedures in place for major interventions such as detecting and handling sick animals and the therapeutic and prophylactic use of chemicals and veterinary medicines.
The people applying these interventions should be trained in all intervenient tasks, as well as in routine tasks. When appropriate the tasks may be prescribed by written instructions or protocols. Consistency in application may also be improved by training, appraisal and further training. Whether obtaining advice or training, this should only be sourced from competent and qualified sources.
CONCLUSIONS
The Task Force has provided a generic set of guidelines for Good Dairy Farming Practices. The section on animal health is robust, applicable to all circumstances yet simple and achievable. It can only be implemented successfully if it is understood, planned and wanted by the dairy farmer. Its sustainability will require realisation of its importance and benefits to the success of the farm. This is a programme where all people involved have to make commitments that endure.
IDF/FAO international symposium on dairy safety and hygiene Cape Town,
2–5 March 2004,
South Africa |
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