Thursday
May052011
Understanding immunity in farming (and life)
Thursday, May 5, 2011 at 8:20AM
Likely you have heard of a vaccine. Perhaps you have even heard they are "bad" and "cause autism" (which is absolutely not true). What is almost always lacking is a clear and correct definition about the functionality of a vaccine - what it actually does. And if you are in the camp who thinks that vaccines are categorically bad and are inherently evil - but at the same time believes that natural food production is the answer to all the world's woes... get ready to confront some serious cognitive dissonance. Since natural and organic farms don't use antibiotics - they typically more likely to vaccinate their herds and flocks against potential maladies (gasp).
Before we can talk about a vaccine we need to understand immunity. Basically there are two types of immunity that an animal (you included) can "have" or experience; active and passive. Active immunity means the immune system is active and working to fight a pathogen (germ, bug, badness... something that's "not self" - not part of the animal mounting the immune response) and build memory against that pathogen. This can be induced by actually getting the disease, where then the body must fight off the invading pathogen, like you getting a cold and then getting better. This can also be induced by vaccination where a non-disease causing version of the pathogen (or only a part of it) is introduced to the body, which makes the immune system actively respond and fight off the pathogen, like you getting a flu shot so you don't get the flu. Both of these scenarios produce an active immunity and the immune system has worked itself to build that immunity. Also important is that there is memory for how this fight was conducted - so this active immunity is long term and can even last a lifetime! A great example is chickenpox - if you got it as a child your immune system remembers the virus it and you won't get it again.
Passive immunity is a little different. It does not involve the immune system actively doing anything (hence the name passive - creative huh?). The immunity, in this case, is simply received - via breast milk or through the placenta, for example. Since the immune system of the animal is not involved in building this immunity, no memory of the act can be built and this type of immunity is not long term. It also means that the immune system did not get the practice or the "workout" involved in building an immune response down the road. Passive immunity is only temporary.
Not even close. Antibiotics are chemicals that disrupt the ability for bacteria (not viruses - they are completely different) from growing... but antibiotics don't "cure you". If you have a bacterial infection antibiotics hopefully slow or stop the spread of the infection and actually let your own active immunity take over and clean the mess up. If your immune system had been primed against the pathogen before you were exposed, the infection might never have gotten established and you might never have needed to take the antibiotic in the first place. Ohh, and taking an antibiotic for every little cold you get - all that does (since colds are viral) is make the bacteria that live in the world around us more resistant to the antibiotic chemical... which means, should you ever NEED an antibiotic it may not be effective in stopping the bacteria and letting your immune system finish the job... that's bad.
Actually quite a lot! Since natural and organic farms don't rely on antibiotics to help fight off nasty bacterial infections in our animals we need to do things that allow our animals to be healthy enough to mount the correct immune response should the need arise. For instance - we COULD overcrowd our chickens, have them live in stressful and dirty conditions and "prevent" infections from getting going in the flock by feeding them an antibiotic medicated feed every day - all day.... OR we could give them very clean spaces, extra room and lots of natural relaxation so their own immune system can take care of the low number of bad "bugs" they encounter just by running around in nature. The fact is many CAFO operations rely on a constant low dose level of antibiotics all the time in their animals since they are perceived as a quick and easy way to deal with or prevent potential infections. However, antibiotic use relies on the chemical antibiotics to destroy or control a pathogen, rather than giving the immune system a workout (and those organisms can and do develop a resistance to the antibiotic making it ineffective). Vaccines induce the natural actions of the immune system to kick in and then build an immune response. And this building of active immunity also means that memory is built, so this is not a one time thing - the immune system is now trained to effectively fight off this pathogen again and again. This might explain why many natural and organic farmers turn to vaccinations to avoid use of antibiotics in their animal feed - since antibiotics use in animals has been shown to develop that bacterial resistance that in turn negatively effects human health. The simple and cost effective vaccinations give the animals immune system the ability to build memory and protect themselves from infections throughout their lives - without ever needing antibiotics (just like in people)!
The reality is a vaccination applied correctly to any animal can impart a totally natural defense against the pathogens that are known to cause disease in that species. For farming operations where those pathogens can become concentrated enough where the animal is at risk for acquiring the disease a farmer must make a choice in prevention - do nothing, vaccinate or apply antibiotics. When it comes to vaccinations you need to look past the fear inspired bad statistics, big money payouts and super helpful "medical science" narratives by former Playboy bunnies from the most un-notable corners of the internet and stick with the scientific facts.
So - with a basic understanding of immunity it's your turn to make a decision that small sustainable farmers make every day.
So how would you tackle this in the role of a local farmer. Let's say you have really clean conditions for brooding and lots of pasture. You are raising a bunch of broiler chickens over the course of the summer in several different batches back to back. Now, the summer is supposed to be damper than normal and you know that adds an element of stress to the chickens you can't control. You also know that there's a particular bug that lives naturally in the soil young chicks can consume resulting in a disease called coccidiosis that can wipe out an entire flock in 24 hours. So let's look at your options and see where your principles for healthy local food meet economics and science fact:
The economic cost of a coccidiosis outbreak is usually considered a total loss. Your investment in the flock of 150 birds is $200 + time and feed... and boy do they eat a lot. Depending on when an outbreak occurs (usually around week 4) you could have $200 dollars in feed already consumed. You can prevent a total flock loss with an immediate application of medicine when the outbreak starts - cost is $20 and at that point 40-60% flock loss. Should there be an outbreak - the subsequent risk to any other chickens living on the farm becomes VERY high and can have farther economic impacts. Also, you should then notify your customers you had to medicate the chickens... and they are thusly no longer organic.
So what would you do?
Option 1) Do nothing special and let nature run it's course. Do your best to create conditions where the chickens will be minimally exposed (as best you can tell) to coccidia which exists in the soil, on plants in the soil and other bird droppings. Hope that the weather will be on your side. Probability of an outbreak is maybe 20% or less using good flock management techniques. An outbreak would reduce your gross profits to a level where that flock would not generate any profit, potentially a loss, and you would have many customers loose their deposit and receive no bird. There should be no impact on bird weight gain using this approach. Prevention Cost = $0 / $150 birds
Option 2) Have your chicks vaccinated before they arrive on your farm. This means before they are shipped that are sprayed with a killed version of coccidia. This allows their young immune systems to learn what the nasty pathogen looks like and be primed to fight it off should it encounter it. Basically generate active immunity (see above). Then, still provide the best conditions you can to the birds so their stress levels stay low and their primed immune systems can respond naturally if needed. Probability of an outbreak is less than 3%, since the chickens are immunized already, providing you are using good flock management techniques. Should there be an outbreak it's likely to spread much slower because of natural immunity so the losses would be much smaller. There should be no impact on bird weight gain using this approach. Cost = $25 / 150 birds
Option 3) Offer your chicks a medicated feed over the first 6 weeks of their life. Since broilers are processed around 7 weeks of age, you stop with the medicated feed 7-10 days before processing and allow for a washout period. Since they are always being "protected" by the medication in the feed the conditions they are raised in are not super important, the medication deals with any coccidia the birds encounter. Some people can be allergic to the medication in the bird meat - but the washout period should take care of that. Probability of an outbreak is less than 10% assuming the flock is not maintained in utterly inhumane conditions BUT you can have more chickens per unit of space so overall you can have a flock that generates more revenue for the same amount of space... so let's a dd a few more birds, if that stresses all of them, the medication will still protect them. If the birds do contract coccidia during the washout period they will likely not be symptomatic but their last week of weight gain may be slightly less. Cost = $20 / 200 birds
Share YOUR answer here!
(And since you are likely wondering what we do - after you give you answer you can follow this link here)
What is immunity (not Survivor Island related)?
Before we can talk about a vaccine we need to understand immunity. Basically there are two types of immunity that an animal (you included) can "have" or experience; active and passive. Active immunity means the immune system is active and working to fight a pathogen (germ, bug, badness... something that's "not self" - not part of the animal mounting the immune response) and build memory against that pathogen. This can be induced by actually getting the disease, where then the body must fight off the invading pathogen, like you getting a cold and then getting better. This can also be induced by vaccination where a non-disease causing version of the pathogen (or only a part of it) is introduced to the body, which makes the immune system actively respond and fight off the pathogen, like you getting a flu shot so you don't get the flu. Both of these scenarios produce an active immunity and the immune system has worked itself to build that immunity. Also important is that there is memory for how this fight was conducted - so this active immunity is long term and can even last a lifetime! A great example is chickenpox - if you got it as a child your immune system remembers the virus it and you won't get it again.
Passive immunity is a little different. It does not involve the immune system actively doing anything (hence the name passive - creative huh?). The immunity, in this case, is simply received - via breast milk or through the placenta, for example. Since the immune system of the animal is not involved in building this immunity, no memory of the act can be built and this type of immunity is not long term. It also means that the immune system did not get the practice or the "workout" involved in building an immune response down the road. Passive immunity is only temporary.
Is an antibiotic immunity or does it make immunity?
Not even close. Antibiotics are chemicals that disrupt the ability for bacteria (not viruses - they are completely different) from growing... but antibiotics don't "cure you". If you have a bacterial infection antibiotics hopefully slow or stop the spread of the infection and actually let your own active immunity take over and clean the mess up. If your immune system had been primed against the pathogen before you were exposed, the infection might never have gotten established and you might never have needed to take the antibiotic in the first place. Ohh, and taking an antibiotic for every little cold you get - all that does (since colds are viral) is make the bacteria that live in the world around us more resistant to the antibiotic chemical... which means, should you ever NEED an antibiotic it may not be effective in stopping the bacteria and letting your immune system finish the job... that's bad.
So what does immunity have to do with local food production?
Actually quite a lot! Since natural and organic farms don't rely on antibiotics to help fight off nasty bacterial infections in our animals we need to do things that allow our animals to be healthy enough to mount the correct immune response should the need arise. For instance - we COULD overcrowd our chickens, have them live in stressful and dirty conditions and "prevent" infections from getting going in the flock by feeding them an antibiotic medicated feed every day - all day.... OR we could give them very clean spaces, extra room and lots of natural relaxation so their own immune system can take care of the low number of bad "bugs" they encounter just by running around in nature. The fact is many CAFO operations rely on a constant low dose level of antibiotics all the time in their animals since they are perceived as a quick and easy way to deal with or prevent potential infections. However, antibiotic use relies on the chemical antibiotics to destroy or control a pathogen, rather than giving the immune system a workout (and those organisms can and do develop a resistance to the antibiotic making it ineffective). Vaccines induce the natural actions of the immune system to kick in and then build an immune response. And this building of active immunity also means that memory is built, so this is not a one time thing - the immune system is now trained to effectively fight off this pathogen again and again. This might explain why many natural and organic farmers turn to vaccinations to avoid use of antibiotics in their animal feed - since antibiotics use in animals has been shown to develop that bacterial resistance that in turn negatively effects human health. The simple and cost effective vaccinations give the animals immune system the ability to build memory and protect themselves from infections throughout their lives - without ever needing antibiotics (just like in people)!
The reality is a vaccination applied correctly to any animal can impart a totally natural defense against the pathogens that are known to cause disease in that species. For farming operations where those pathogens can become concentrated enough where the animal is at risk for acquiring the disease a farmer must make a choice in prevention - do nothing, vaccinate or apply antibiotics. When it comes to vaccinations you need to look past the fear inspired bad statistics, big money payouts and super helpful "medical science" narratives by former Playboy bunnies from the most un-notable corners of the internet and stick with the scientific facts.
So - with a basic understanding of immunity it's your turn to make a decision that small sustainable farmers make every day.
Would you vaccinate your chickens?
So how would you tackle this in the role of a local farmer. Let's say you have really clean conditions for brooding and lots of pasture. You are raising a bunch of broiler chickens over the course of the summer in several different batches back to back. Now, the summer is supposed to be damper than normal and you know that adds an element of stress to the chickens you can't control. You also know that there's a particular bug that lives naturally in the soil young chicks can consume resulting in a disease called coccidiosis that can wipe out an entire flock in 24 hours. So let's look at your options and see where your principles for healthy local food meet economics and science fact:
The economic cost of a coccidiosis outbreak is usually considered a total loss. Your investment in the flock of 150 birds is $200 + time and feed... and boy do they eat a lot. Depending on when an outbreak occurs (usually around week 4) you could have $200 dollars in feed already consumed. You can prevent a total flock loss with an immediate application of medicine when the outbreak starts - cost is $20 and at that point 40-60% flock loss. Should there be an outbreak - the subsequent risk to any other chickens living on the farm becomes VERY high and can have farther economic impacts. Also, you should then notify your customers you had to medicate the chickens... and they are thusly no longer organic.
So what would you do?
Option 1) Do nothing special and let nature run it's course. Do your best to create conditions where the chickens will be minimally exposed (as best you can tell) to coccidia which exists in the soil, on plants in the soil and other bird droppings. Hope that the weather will be on your side. Probability of an outbreak is maybe 20% or less using good flock management techniques. An outbreak would reduce your gross profits to a level where that flock would not generate any profit, potentially a loss, and you would have many customers loose their deposit and receive no bird. There should be no impact on bird weight gain using this approach. Prevention Cost = $0 / $150 birds
Option 2) Have your chicks vaccinated before they arrive on your farm. This means before they are shipped that are sprayed with a killed version of coccidia. This allows their young immune systems to learn what the nasty pathogen looks like and be primed to fight it off should it encounter it. Basically generate active immunity (see above). Then, still provide the best conditions you can to the birds so their stress levels stay low and their primed immune systems can respond naturally if needed. Probability of an outbreak is less than 3%, since the chickens are immunized already, providing you are using good flock management techniques. Should there be an outbreak it's likely to spread much slower because of natural immunity so the losses would be much smaller. There should be no impact on bird weight gain using this approach. Cost = $25 / 150 birds
Option 3) Offer your chicks a medicated feed over the first 6 weeks of their life. Since broilers are processed around 7 weeks of age, you stop with the medicated feed 7-10 days before processing and allow for a washout period. Since they are always being "protected" by the medication in the feed the conditions they are raised in are not super important, the medication deals with any coccidia the birds encounter. Some people can be allergic to the medication in the bird meat - but the washout period should take care of that. Probability of an outbreak is less than 10% assuming the flock is not maintained in utterly inhumane conditions BUT you can have more chickens per unit of space so overall you can have a flock that generates more revenue for the same amount of space... so let's a dd a few more birds, if that stresses all of them, the medication will still protect them. If the birds do contract coccidia during the washout period they will likely not be symptomatic but their last week of weight gain may be slightly less. Cost = $20 / 200 birds
Share YOUR answer here!
(And since you are likely wondering what we do - after you give you answer you can follow this link here)
Andy |
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antibiotics,
chickens,
commentary,
disease,
farming,
immunity,
sustainability,
vaccination in
Animals,
Farm Life,
Politics or Other Rants 
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