Category Archives: Animal Health

Vaccines are not dosed in the same way as antibiotics. This concept is even more relevant for vaccines against coccidiosis in poultry

A vaccine dose does not depend on body weight: the mechanism of action of vaccines is different to that of antibiotics and, as a result, the dose does not depend on the body weight of the target animal. When considering vaccines against coccidiosis in poultry, the dose is made up of a suspension of sporulated oocysts of different species of Eimeria.


In this suspension, the oocysts are not evenly distributed unless it is mixed thoroughly. If, in addition to this, the dose is reduced, the chance that the chicks will receive all the oocysts of every species decreases exponentially.
A vaccine does not have to be distributed throughout the body and the vaccine components (antigen and adjuvant) do not act directly on the pathogen. In general, the activity of vaccines starts with a rapid and local innate response depending on the route of administration.

Usually vaccines against coccidiosis in poultry are administered orally, thus the first innate immune response takes place in the gut. As a result of this first phase, antigen-presenting cells are activated (dendritic cells and/or macrophages) that are responsible for processing the antigen and carrying it to Peyer patches where they activate specific T lymphocytes, thereby starting the acquired immune response. As Eimeria is an intracellular parasite, the acquired immunity needed is of the cellular type. In this second phase, effector T cells are generated that produce cytokines ensuring a concentration in the tissues that is independent of the age/weight of the animal for the same dose of vaccine.
Does the same thing happen with human vaccines?
In human medicine, the vaccines that are used in children (paediatric vaccines) and in adults are the same and are used in the same dose. It would not occur to anyone to reduce a vaccine dose for children because of the risk of inadequate protection that this would entail. There are examples of toxoids (tetanus), inactivated vaccines (rabies) and live vaccines (varicella) where the dose is the same for children as for adults.
How is a vaccine dose determined?
The dose that is indicated in the leaflet for each vaccine is the one that has been shown to be effective during the different research phases in the target animal species and with the minimum age that can be vaccinated. On the basis of these studies, the health authorities in each country recommend the specified dose for each product. For this reason, the dose should be administered irrespective of the age of the animal.
There are some older products that have different doses for different age groups, but this would not be allowed nowadays.
What harm can be done by a dose that is lower than the recommended one?
Administration of a vaccine dose that is lower than the recommended one can result in a lower immune response, compromising the protection of the individual against the pathogen. Specifically, with vaccines against coccidiosis in poultry, if a full dose is not administered, there is a very strong possibility that there will be an uneven administration of both oocysts and Eimeria species amongst the vaccinated animals with a consequent lack of onset of immunity in some of the chicks.

Dealing with coccidiosis by reducing the use of antibiotics: is it sustainable? (Part 2)

It is our responsibility to search for and choose the right tools to deal with coccidiosis in poultry with current consumer preferences tending towards the purchase of products from livestock grown using sustainable methods.

Because of worldwide concern about drug resistance associated with the immoderate use of antibiotics in poultry production, there has been a major effort to find alternative treatment and methods of prevention.

There is a greater demand for products from sustainable livestock and the higher prices may encourage the farmer. All these factors are in addition to the strongly held beliefs of many consumers that broilers reared with less antibiotic use not only provide additional health benefits to them and their families, but also that sustainable farming practices provide long-term environmental benefits.

It is well known that the major use of antibiotics in poultry farming is linked to coccidiosis prevention and treatment. Therefore, this is the starting point for thinking about reducing their use.

First of all, a biosecurity program needs to be implemented and well managed. It is an everyday goal. The program should address points such as controlling access by individuals, cleaning and disinfection, feed and water quality, access by other animals.

The second step is to study the available alternatives for dealing with coccidiosis. Researchers like Niewold in 2007 have suggested that the unique and highly reproducible effects of in-feed antibiotics may be due to the prevention of immunological stress or their anti-inflammatory effect rather than their antimicrobial role, and this should be considered when searching for new compounds to be used as replacements.

Since we know that prevention it is a key point in sustainable animal farming, vaccination is an important tool to be considered.

Over the past 10 years, experiences in the field have provided data regarding this cost/benefit ratio, derived from the use of rotation programs with precocious attenuated vaccines, such as HIPRACOX®.

Rotation programs allow the poultry farmer to decide on the use of fewer preventive antibiotics – anticoccidials – and to decrease coccidiosis lesions, which means less use of antibiotics as treatment.

This is a long term plan, in which every decision must be taken in a responsible way. Using the right tools, success can be achieved in the matter of coccidiosis with the use of sustainable methods.
References:

Niewold T.A. 2007. The nonantibiotic anti-inflammatory effect of antimicrobial growth promoters, the real mode of action? A hypothesis. Poultry Science, vol. 86 (4), 605-609.

Dealing with coccidiosis by reducing the use of antibiotics: is it sustainable? (Part I)

One of the most worrying problems in poultry production is coccidiosis and how to deal with it without using antibiotics. It is a challenge that, we know, lies in prevention. Furthermore, it is impossible to think in terms of prevention and not to link this to sustainable action.


Thinking sustainably is to link the human population, animals and the environment into every decision or action. It is believing that the world is entirely interconnected.

The concept of One Health was envisaged and implemented by the OIE in the early 2000s as a collaborative global approach to understanding the risks to human and animal health and ecosystem health as a whole, and has everything to do with sustainable action.
Global sustainability affects veterinary medicine on a significant scale, and it is a particular challenge. Since the veterinary professionals play key roles in different parts of the ecosystem, it is necessary for them to understand what is happening in almost every other area of knowledge. Moreover, veterinary medicine is the only profession that routinely operates at the interface of these three components of One Health.
It is important to say that sustainable ways of thinking also look at economic aspects, which are needed for efficient production.
With regard to the poultry industry, it is impossible to make any decision without taking into account the health aspect. Every management plan looks first at the birds’ health because it is something that is influenced by every factor on a farm: buildings, nutrition, welfare.
The importance of digestive diseases is well known and, amongst these, coccidiosis can be named as one of the major health problems, and how to deal with it has been widely discussed during recent years. However, nowadays, there is a great deal of concern about the use of antibiotics in the poultry industry. The widespread use of anticoccidials or antibiotics has led to a resistance problem, which means that many of these drugs are no longer effective. One approach to be considered is to decrease antibiotic usage so that fewer numbers of bacteria are exposed to antibiotics and fewer resistant genes develop. Unnecessary use of antibiotics has been identified, and government associations are recommending a reduction in their usage (e.g. White House, 2015. National Action Plan for Combating Antibiotic-resistant Bacteria Washington, DC pp. 1–62).
Keeping the sustainability aspect in mind, it is to be recommended that poultry farming should focus on prevention rather than treatment. Indeed, in veterinary medicine, prevention and sustainability could be synonymous.
The prevention of coccidiosis without the use of anticoccidials or antibiotics is now a reality for forward-looking farms. There is increasing awareness amongst consumers about the products they purchase. They want to know how the animal was raised and processed, besides what sustainable practices were applied during the process chain.
It is a win-win situation: famers guarantee a standard of flock health, consumers purchase sustainable products.

Doses in the administration of Animal Health vaccines

Vaccines are not dosed in the same way as antibiotics.

A vaccine dose does NOT depend on body weight: The mechanism of action of vaccines is different to that of antibiotics and, as a result, the dose does not depend on the body weight of the target animal. A vaccine does not have to be distributed throughout the body and the vaccine components (antigen and adjuvant) do not act directly on the pathogen. In general, the activity of vaccines starts at the inoculation site itself by means of a rapid and local innate response. As a result of this phase, antigen-presenting cells are activated (dendritic cells and/or macrophages) that are responsible for processing the antigen and carrying it to the closest lymph nodes where they activate specific T and B lymphocytes, thereby starting the acquired immune response. In a second phase, effector T cells and B plasma cells are generated that produce cytokines and antibodies respectively, ensuring a concentration in the blood and tissues that is independent of the age/weight of the animal for the same dose of vaccine.

Does the same thing happen with human vaccines?

In human medicine, the vaccines that are used in children (paediatric vaccines) and in adults are the same and are used in the same dose. It would not occur to anyone to reduce a vaccine dose for children because of the risk of inadequate protection that this would entail. There are examples of toxoids (tetanus), inactivated vaccines (rabies) and live vaccines (varicella) where the dose is the same for children as for adults.

How is a vaccine dose determined?

The dose that is indicated in the leaflet for each vaccine is the one that has been shown to be effective during the different research phases in the target animal species and with the minimum age that can be vaccinated. On the basis of these studies, the health authorities in each country recommend the specified dose for each product. For this reason, the dose should be administered irrespective of the age of the animal.

There are some older products that have different doses for different age groups, but this would not be allowed nowadays.

What harm can be done by a dose that is lower than the recommended one?

Administration of a vaccine dose that is lower than the recommended one can result in a lower immune response, compromising the protection of the individual against the pathogen.

Key points in the diagnosis of coccidiosis (Part 2: Lesion Scoring)

When decisions concerning the prevention or control of coccidiosis in poultry are based on the subjective scoring of macroscopic lesions, observed in the gut of a number of birds in a flock, several factors affecting the method should be considered. Proper selection of birds, a careful sampling procedure and sample handling along with an accurate judgment of lesions, are some of the most important methodological indicators for success in lesion scoring during a flock inspection.


1. Selection of the right birds in the right number:

Before necropsy, it is essential to check the history of vaccinations, treatments (anticoccidials in particular) and previous diagnoses of the flock to be sampled. It has been shown that the existence of gut lesions is not necessarily accompanied by clinical signs of coccidiosis in poultry (Williams et al., 2000).
In fact, the score that has been used for decades was developed in naive birds (Johnson et al., 1970). However, it has been shown that immunized birds may display lesions and high oocyst counts, with no growth retardation or clinically overt disease. In these cases the lesions are of no economic significance.
As for the number of birds to be examined, it is necessary to seek the right balance between the need to evaluate a representative sample of the batch of birds, and the willingness of the farmer to provide enough birds. Generally, a total of 5 to10 broilers, 25-35-days old, from each house would be reasonable. These birds should be of the average weight of the batch, and be alive at the time of sampling, not debilitated or fasted.
2. Sampling:
As previously mentioned, it is crucial that birds examined for gross lesions (at least 5 per batch), are alive and within the appropriate age range. If multiple groups are inspected, it is better to sacrifice one group and then another to reduce post-mortem artifacts. It is equally important that, as far as possible, the inspections are always carried out by the same person who evaluates the different batches of birds coming from the same farm. This is mainly because their experience enables them to reduce the variation inherent in the scoring system.
The intestine is the first organ to decompose after death. Postmortem changes negatively influence the assessment of pathological changes in the gut. Make the sacrifice humanely with the least possible stress. The preferred euthanasia method on the farm is generally cervical dislocation. This should be carried out by trained staff because if not done quickly and effectively, it can inflict pain and distress. Sacrifice by carbon dioxide inhalation is another valid alternative, if it is available.
3. Sample handling:
To complete the inspection in a systematic way, consider the four segments of the intestine that are shown in Figure 1. Do not expose the inner surface of the intestine until you have inspected the outer wall. It is important to record any change in thickness, colour or presence of spots that may be indicative of injury.
Expose the inside of the digestive system including the gizzard, proventriculus and cloaca. Do it using a different scissors and forceps kit for each group of animals. Observe and describe the content found (amount and appearance), as well as any other signs that catches your attention. Inflammation of the intestine can sometimes be identified immediately after cutting the wall longitudinally, as it tends to fall back on itself.
This only happens when it belongs to a bird that has been recently sacrificed. List all the lesions observed, their exact location, colour, appearance, distribution, shape, etc. Whenever possible, take photos of the lesions found.

There are seven Eimeria species that are responsible for avian coccidiosis, 5 of which cause the disease in broilers: E. acervulina, E. mitis, E. tenella, E. maxima and E. praecox.

Finally, close collaboration between the veterinarian and the farm staff is crucial to avoid possible biases of the method, or the over-interpretation of the lesions found. The availability of detailed information on health management of the flock, and the right amount of suitable birds for inspection will be very important, before making decisions on the control of coccidiosis based on the results of inspections and lesion scoring.

Key points in the diagnosis of coccidiosis (Part 1: Identifying and counting oocysts)

The prerequisite for the control and treatment of coccidiosis in poultry is to correctly identify the presence of disease. Two of the most widely used methods for this purpose are the identification and enumeration of oocysts, and the identification of lesions in the intestine. Although egg identification and counting was described for decades, and has been used since then, it is important to consider some key aspects of the method to obtain valid results.


1) Be familiar with the morphology of the parasite:

Have skills to identify the Eimeria species is the main element to be considered for the success of the morphometric study of field samples. For this, it is convenient to train yourself using pure parasite suspensions obtained in the laboratory.
Although field samples differ greatly from these suspensions (Figure 1), particularly as regards the debris and impurities contained, if they are well preserved (refrigeration at 4-8ºC) the typical morphology of each Eimeria species is easily recognizable.Once familiar with the microscopic appearance, experience after analyzing many samples is what allows you to refine the method, always with an error range due to the “atypical” forms that can be found in all field samples.
2) Use only samples in good condition:
Counting and identification of oocysts, like any other diagnostic method, requires samples to be preserved in good condition. There is, however, a trend to believe that Eimeria oocysts are “indestructible”.
Whilst these parasitic forms are among the most resistant known, their shape can be altered if the oocyst ages or matures (sporulates) over time, particularly when the temperature and humidity are favorable. To avoid this disadvantage, it is very important that the samples are fresh (preferably <7 days after being collected) and remain stored under refrigeration until they are analyzed.Thus maturation is prevented and the number of atypical forms is reduced.
3) Place your confidence in a certified laboratory that provides a guarantee:
Not all laboratories perform the identification and counting of Eimeria oocysts in exactly the same way. However, there are some requirements that must always be met, if valid, repeatable and accurate results are expected. The validity is mainly linked to the prevention of cross-contamination among samples. The possibility of getting false positive results by cross-contamination in the laboratory is very high, particularly in places with a high workload. Thus, practices such as using disposable and sterile materials, changing gloves between critical steps in the procedure, etc., are crucial.
On the other hand, the robustness and accuracy depend very much on the use of calibrated instruments and validated methods. Some key points are the correct homogenization of the sample before processing, weighing accuracy, the use of the correct dilution factor, and a microscopic observation method without artifacts.
Finally, before making decisions about the treatment of coccidiosis based on the laboratory results, it is important to consider that Eimeria is prevalent and is found in the faeces and intestines of poultry.
Therefore the significance of this finding must be weighed against other indicators of disease, such as the presence of clinical signs in live animals, as well as macro lesions and microscopic lesions in the intestine.

Is it possible to administer a live PRRS vaccine to animals already infected to stop the piglet’s infection?

Summary: 

Vaccinating the infected sows with a PRRS live vaccine does not seem to help to reduce the clinical signs. It normally reduces the clinical signs in sows when the vaccination is administered before the infection with the field virus. The non-immunised gilts are animals that can help in the replication of the virus on unstable positive farms, and because of this, the vaccination and adaptation before their introduction on the farm is recommended to reduce the clinical signs in these animals and to lower the circulation of the virus on the farm.


You can ask your own question! Visit Pig333.com and submit your question to our experts. 

A PRRS outbreak is causing 40% of stillborn piglets. Is it possible to administer a live vaccine to animals already infected to stop the piglet’s infection? Could a vaccine of this kind reduce the number of dead piglets and stop the transmission to new litters?

In this case, an outbreak of stillborn piglets (around 40%) is described, and it is suspected that the cause is PRRS. When we ask for more information on the case, we are told:

Most of the affected litters belong to first parity sows.

No PCR diagnosis of PRSSV on deadborn piglets has been carried out.

Gilts come from another farm, their health status regarding PRRS is unknown, and they are not vaccinated.

The semen used for AI has an external origin.

Vaccinating a newly infected animal with the PRRS field virus does not have practical advantages for the animal, because the immune system already has a strong antigen to process the answer needed. The difficulty does not lie in the individual animal, but on an animal population, because not all the animals become infected at the same time. The PRRS virus is not very contagious, and because of this, the contamination of all the sows on the farm with the field virus will take a long time if we leave the virus to circulate naturally. In these cases, the clinical symptomatology will go on until the last sow becomes immunocompetent against the virus. This can take several months or even years, when negative subpopulations appear on positive farms.

PRRSV-naive gilts are another source of active virus replication when they enter an unstable farm with an active virus circulation. In this case, a situation like the one described can appear. Nevertheless, to be sure, we must diagnose if the PRRSV is the agent responsible for the mortality of the piglets.

If the PRRSV diagnosis is confirmed in the piglets and the gilts that come from an external source, the next step is to reduce the virus circulation on the farm, mainly in the gilts, that may be where the virus proliferates. In cases like this, we recommend vaccinating all the sows to induce some kind of immunisation against the PRRSV and to reduce the clinical symptoms in the sows NOT infected at the time of vaccination. We are not going to avoid the infection of new litters with the field virus, but we can reduce its negative impact and the clinical signs if there is an immunisation previous to the infection.

There is the risk of not achieving enough immunological protection against the field virus with some vaccines, but as of today there is not a technology that allows us to say, with confidence, which is the most effective vaccine for a certain farm. Even after sequencing the virus and choosing the vaccine with the highest homology degree, nothing guarantees us that it will be the most effective one on the farm.

The strategy that we use in clinical outbreaks like this (with a confirmed PRRS diagnosis) is:

The vaccination of all the sows and boars on the farm with a live vaccine on the same day (we will vaccinate the most immunodepressed sows the following week: on the insemination/mating week and the farrowing week). The goal is to obtain a quick immune response against the PRRSV in all the sows in the group, and we expect a certain degree of cross-protection between the vaccine and the field strains. Revaccinate 4 weeks later with the same protocol. 

The gilts that enter the pregnancy stage must be well immunised and non-viraemic (PCR-negative to PRRS and IgG-positive). The vaccination and adaptation of viraemic animals on the farm and allowing enough time in quarantine until they do not excrete the virus (12 weeks is normally enough) are recommended. This is very important for the future control of PRRS on the farm. 

Buying PRRS-negative semen to inseminate the sows. 

Knowing if the virus is circulating in the nurseries. If there is circulation, implement biosecurity rules to reduce the transmission of the virus to the sow herd. 

After the second vaccination of the sows, evaluate if there are still viraemic piglets at birth. If this improves, we can keep the vaccination and adaptation programme only in the gilts in quarantine. 

Is it possible to rear broilers without antibiotics? First step to achieve the goal: vaccination against coccidiosis in chickens

Prevention of coccidiosis in chickens with live vaccines means suspending the use of anticoccidials, but a reduction in other antibiotics has also been observed. Reduction in antibiotic use in animal production is currently one of the aims of the poultry industry. Antimicrobial resistance has become a global public health problem in humans and livestock and plans to reduce the use of antibiotics are being implemented by the authorities in most countries.


Obviously, chemicals and ionophores used to control coccidiosis should be considered as antibiotics because the parasites that are intended to be controlled with these products can develop resistance with prolonged use of these substances.

Vaccination against coccidiosis in chickens has an indirect effect on gut-related diseases (dysbacteriosis, necrotic enteritis, septicaemia after gut leakage) and the consumption of antibiotics could therefore be altered.
It has already been seen that the implementation of a coccidiosis vaccine (HIPRACOX®) in a rotation programme yields a significant improvement in zootechnical results (Ronsmans et al. 2015a). Hipra, in collaboration with the poultry practice Galluvet in Belgium (Ronsmans et al. 2015b), has conducted a study to determine whether vaccination with HIPRACOX® affected the use of antibiotics in broilers. The hypothesis was that if intestinal health was enhanced, the overall health of broiler farms would improve.
In the trial, the effect of the administration of HIPRACOX® on the use of antibiotics on 21 farms in Belgian field conditions was studied. The trial was conducted on the premise of the benefits of rotational programmes but we realised that the use of the vaccine could have a positive effect on reduced antibiotic use during the rearing period.
Some of the farms had a background of coccidiosis problems. Under these circumstances, the use of a coccidiosis vaccine offered adequate protection and there was a clear and significant reduction of treatments against coccidiosis in chickens. As we can see in Graphs 1 and 2, the number of days of treatment fell by 79.56% during the vaccination and by 51.38% after the vaccination cycles (see image above).
However, more significant still is the fall in the administration of gastrointestinal treatments during the period of use of HIPRACOX®. We evaluated the consumption of molecules used to improve intestinal pathologies (Tylvalosin, Linco-Spectin, Tylosin, Penicillin and Amoxicillin).
The graphs below show the evolution of their use on the farms before the administration of HIPRACOX®, during administration of the vaccine and after. The days of treatment per cycle fell by 16.4% during vaccination and by 45.24% after vaccination. Moreover, the amount of active molecule per kg of average weight decreased by 17.39% during and 30.4% after vaccination.

Popular belief tells us that more cases of necrotic enteritis and dysbacteriosis appear in vaccinated flocks due to the lack of the anticlostridial effect of the ionophores. However, no cases of necrotic enteritis were seen during the trial. Furthermore, the quantity of antibiotics used for enteric diseases fell in the period in which the vaccine was used. These observations are consistent with the review conducted by Williams (2005).

Once again, prevention in broiler production is key. A good vaccination programme including vaccines against coccidiosis in chickens could be the best option for those producers that are considering reducing or even phasing out the use of antibiotics on rearing broilers.
In conclusion, the first aim of a coccidiosis vaccine is to prevent coccidiosis in chickens but an indirect effect of coccidiosis vaccine on other diseases can be expected, probably due to an improvement in intestinal integrity.

HIPRA digitalise the animal vaccination process with Watson IoT technology in the cloud of IBM

The service is already available for veterinarians and farmers worldwide. 

www-03.ibm.com/press/es/es/pressrelease/50682.wss

Madrid – 29 sep 2016: IBM and HIPRA have announced an agreement to integrate the Internet of Things (IoT) solutions that are available in the IBM cloud with animal vaccination   This Technology allows HIPRA to be in the forefront of the Animal Health market. HIPRA name this new world as “the Smart Vaccination” concept, and they are the pioneers in developing this new concept in Animal Health.  

The Smart Vaccination concept is a turning point and there will be a new era after the IoT arrival to animal farming. The Smart Vaccination is a new world where HIPRA vaccines are connected to HIPRA’s Medical Devices and HIPRAlink (HIPRA’s software) to offer vets and farmers a new world of services and benefits for the Prevention of diseases.

Can Eimeria vaccines replace anticoccidials for the prevention of coccidiosis in poultry farming?

Coccidiosis – due to parasites of the genus Eimeria – is one of the most devastating diseases in poultry: a disease which has always being present in every poultry flock since the first chick appeared on the earth; in fact, Eimeria is an ever-present parasite that it is impossible to eradicate. For this reason, a coccidiosis prevention strategy needs to be put in place for each batch of chickens that arrives on a farm. Worldwide losses due to coccidiosis in poultry are estimated to be around US$1.5 billion/year.


From the 1950s the use of some chemical molecules has been implemented to prevent the effects of the several Eimeria species that cause the disease. Whereas the use of vaccines is quite commune in breeders, only between 5 and 6% of broilers in the world are actually vaccinated instead of being treated with anticoccidials.

The prevention of coccidiosis in poultry with some Eimeria vaccines is absolutely safe and efficacious as also demonstrated recently by Alameda et al. 2015 and Ronsmans et al. 2015. So the question is, why is the prevention of coccidiosis with the vaccines available not more widely used around the world? In this post I will try to answer this question from several perspectives.
The first important question to answer is whether or not it is possible. The answer is clearly yes it is. The entire production of breeders, free-range or organic chickens and a percentage of the industrial production of broilers are produced today without the use of anticoccidials. So, the first thing to take into account is the willingness of broiler producers to do it.
The second question is the cost. Some people think that vaccines are more expensive than anticoccidials, but this is not always true. It depends on the duration of fattening of the broiler, the anticoccidial programme used and, of course, on the quality of the final broiler produced, whether or not it is free of anticoccidials.
The third question is management. Some producers think that the use of anticoccidials in the feed is much simpler than vaccination. But it is not well known that the use of anticoccidials in the feed could potentially lead to cross-contamination in the feed mill, especially when the plant produces feed for more than one animal species. This could be the case with salinomycin in turkeys: salinomycin is one ionophore widely used in broiler feed as an anticoccidial, whereas it is well known that it is very toxic for turkeys, even at levels lower than therapeutic ones (Potter et al. 1986). Moreover, it has to be recalled that nowadays the administration of Eimeria vaccines is becoming more and more practical and standardised as most of the applications – especially for broilers – are performed in the hatchery with spraying devices that have been designed for this specific use, like Hipraspray®.
Finally, there is another important question to answer which is whether the availability of vaccines would be sufficient to replace anticoccidials completely. The answer to this question is not easy. Of course companies producing Eimeria vaccines do not produce sufficient quantities at present, because there is no need for it. However, if broiler production in the world started to demand Eimeria vaccines, there’s no reason to think that given time, the companies would not have a sufficient amount of vaccines available.
Eimeria vaccines have a short shelf-life, so they have to be manufactured in response to demand because they cannot be stored for more than a few months. But, again, this is not a very important problem due to the fact that the modern poultry production system is so industrialized that vaccinations can be planned easily and with a long notice period. For this reason, the production of vaccines can be easily planned and in the most accurate way.