Does anyone know lasting effects of CRD as Chicken grows?

Discussion in 'Emergencies / Diseases / Injuries and Cures' started by lockedhearts, Sep 9, 2008.

  1. lockedhearts

    lockedhearts It's All About Chicken Math

    Apr 29, 2007
    I tried searching but couldn't find anything other than general info about CRD. I have a BO Rooster hatched late March/Early April (got him in a trade) lost all other chicks but him and an older Pullet to CRD (the pullet never showed any signs)
    He fought hard to live and overcame the disease. I kept him alone in a tote in the house for a long time until I was sure he was free and clear.
    He did take much longer to feather out than other chicks about his age.
    He has yet to crow and is very obviously a rooster. I am wondering if the degree of CRD he had affected his crowing ability? I am also wondering, since I plan to keep him as part of my BO Flock, if it is possible that it could affect his fertility.
    He is totally healthy now and is a big healthy rooster.
  2. speckledhen

    speckledhen Intentional Solitude

    I can find things such as the following, but nothing that really says what effects it has, long term, except that they will continue to carry the disease and can infect others when under stress:

    Chronic Respiratory Disease (CRD) is a complex respiratory disease whose root cause is an infection by Mycoplasma Gallisepticum (MG). The MG infection is almost always accompanied with another infection whether, bacterial or viral. The MG infection can be controlled thru medications and vaccinations, however once a bird is infected there is no cure. The secondary infections can be cured thru medication in the case of bacteria or thru the birds immune system, in the case of viral infection. Therefore, as there is no cure for MG the respiratory infections will re-occur with every new bacterial or viral respiratory infection. To add to this complex problem, stress whether it be from a severe change in the weather, poor management, working the bird or whatever, makes the bird more prone to an outbreak.

    The signs and symptoms are varied, depending on how severe the infection is, the general health of the bird, what secondary infections are present and how much stress the bird is under. A squeaky crow along with respiratory rattles are usually the first signs. Bubbles in the eyes are very characteristic which can be followed by nasal discharge. Birds, when worked, will be short winded, have very little energy and will become blue headed if the disease is severe. In severe infections the bird will have a fever and will develop diarrhea or the greens and will lose weight.

    MG is spread by many means. It is passed thru the egg from one generation to the next. The disease can be carried thru the air for short distances, be carried by wild birds and animals, be transmitted by direct contact or by sharing feed and water cups, and very importantly, by yourself on hands, clothing, or shoes.

    Tylan is the drug of choice and will control the disease very well. Tylan can be given by injection or thru the drinking water. LS-50, Spectam, Gallimycin and Tetracycline are also effective. There are live and killed vaccines for the control of MG. The use of live vaccines are controlled in some states and there reactions are sometimes very strong, making live vaccines a second choice to killed vaccines. Killed vaccines offer long term control with very little risk. Also these killed products are now available in combination with Newcastle and Bronchitis, making the 3-way vaccine a broad protection product.

    MG which is the cause of CRD, is a problem which must be and can be kept under control. Everyone should know if he is infected so he can control the problem or if he is clean so he can work to stay that way. The only sure way to know your status is by blood testing your birds.

    This is good, the way it's broken down and very clear:

    Chronic respiratory disease (CRD) is one of the most common respiratory diseases of poultry. The disease occurs when birds infected with Mycoplasma gallisepticum are stressed. The subsequent invasion by secondary bacteria causes the major damage to the bird.

    Scientific name
    Mycoplasma gallisepticum plus other organisms

    CauseMycoplasma gallisepticum
    + Chronic stress factor
    + Secondary coliform organisms

    Species susceptibleChickens

    IncidenceVery widespread and present in most commercial flocks

    CRD is the most prevalent of the so called 'stress diseases' and outbreaks occur most frequently at times of stress:

    Beak trimming
    Poor ventilation
    Damp litter
    Ammonia build-up
    Other diseases
    However, transmission may occur in flocks that appear to be perfectly healthy.

    1. Egg Transmission
    Major importance as the means by which the disease perpetuates itself

    2. Airborne (aerosol)
    Generally rapid, but does not travel long distances

    3. Indirect or mechanical

    Infected Carrier birds
    Persons such as service personnel
    Vaccinators and blood testers
    Equipment (crates, vehicles, and vaccinating equipment)

    Incubation period Incubation is 5 to l0 days.
    Wet noses
    Retarded growth in growing birds
    Production loss (20 to 30%) in hens
    Deaths are few in uncomplicated cases
    The disease spreads slowly through the flock and there is a continual cycle of re-infection so that the disease never disappears by itself.

    Financial losses are due to:

    - Poor feed conversion
    - Retarded growth
    - Drug costs
    - Mortality
    - Increased culling
    - Poor production

    Diagnosis may prove trickyIsolation of mycoplasma is difficult
    Must be confirmed to be Mycoplasma gallisepticum (other types of Mycoplasma exist)
    Blood tests vary in reliability

    Post mortemMucus in the trachea, sinuses and bronchi
    Cloudy, thickened air sacs

    Similar diseasesCoryza
    Infectious bronchitis
    Infectious laryngotracheitis
    Fowl cholera

    Treatment1. Antibiotics:

    Help control the disease
    Minimise secondary bacterial complications
    Do not control the disease completely
    2. Flock management:

    Control stress factor
    Isolate young birds from older birds
    Isolate affected groups (50 to 100m apart)
    Buy vaccinated pullets
    All-in, all-out management

    Prevention1. Antibiotics:
    The organism may be present in a flock without producing any signs of disease. It will spread slowly to other birds until the birds are 'stressed' when it will spread more rapidly.

    => Where CRD is a problem: Treat the flock before the birds are stressed

    - In the first 3 days of life

    - At four weeks of age

    - At maturity

    These measures may not prevent the disease but will lessen the likelihood of an outbreak.

    2. Vaccination:
    Pullets reared in isolation can be vaccinated to prevent infection with Mycoplasma gallisepticum.​
    Last edited: Sep 9, 2008
  3. lockedhearts

    lockedhearts It's All About Chicken Math

    Apr 29, 2007
    So I am wondering if I should even attempt to use him to breed? He is very obviously healthy now and does all the things any other healthy chicken does, except crow.
    I have almost $150 in him for the medicine I put in him trying to save him.
    Dang, now I am wondering if I should have culled him back then.
  4. speckledhen

    speckledhen Intentional Solitude

    I added an article to the above post I made, K. I'm not sure what to tell you. My personal choices may not be for everyone. Only you can decide what you should do in a case like that. I know that CRD is passed through the egg, but not sure if they have to be actively symptomatic at the time to do that and if it's just then hen who lays the egg that can pass it or the sire of the chick.
    Last edited: Sep 9, 2008
  5. lockedhearts

    lockedhearts It's All About Chicken Math

    Apr 29, 2007
    I saw that after I posted. Dang, so maybe I have a $150 house chickens , yeah not with my dogs.
    Darn it......
    I assumed he had CRD as this is what his symptoms were most closely related to, I suppose it is possible he had something else.
    As far as stressed, other than not particularly liking me to pick him up (probably flash backs from all the medicating when he was sick) he is one pretty laid back chicken, he doesn't get particularly upset or out of sorts about anything going on.
    He certainly eats well as he is one of my heavier birds.

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