Respiratory sickness in ostriches: Air sac infection
24 August 2006
THE RESPIRATORY SYSTEM OF THE OSTRICH (nose, windpipe or trachea, air sac and lungs) provide the heart
and vascular system with oxygen to spread it throughout the body. Carbon dioxide is returned to the
respiratory system to be exhaled.
Except for the exchanges of gases, the respiratory system also has many other functions. It maintains the chemical balance in the body, as well as the degradation or edification of various products the body needs to function in a normal manner. The airways are crucial for smelling and maintaining body temperature. Should the functioning of the airways of an ostrich be obstructed, it has far-reaching consequences for the ostrich.
Special protection mechanisms in the airway of the ostrich include fine hairs, a mucous layer and white blood cells that take in and destroy foreign particles.
The seriousness and economic impact of airway infections in ostriches are determined by the population density, herd size and age.
The respiratory problems in ostriches are the result of intensification associate with the increase in population
density and stress. The illness has direct and indirect consequences.
- Erosion sickness: Higher feed usage and longer time before ready for slaughter.
- Disapproval of ribcages (8,8%) or total carcass (0.5%).
- Increased susceptibility to secondary infections that could lead to higher mortality rates.
- Treatment costs, especially in high sickness rate.
The ostrich-specific mycoplasma organism, as discovered by the research team of KLEIN KAROO International, is associated with signs of air sac sickness. A carrier condition of mycoplasma is often present.
Other: Haemophilus and fungus. Newcastle and Influenza virus can cause signs of respiratory illness as well.
- Weather changes are especially important during autumn and spring as a result of temperature fluctuations.
- Stress: Especially transport-related stress (long distances, cold and without food); changes in feeding
(regular fresh high value feed after new type of ration in new feeding troughs); surroundings (from protected
chicken camps to open feeding pens); social stress (classification and mix with new chicks).
- Hygiene: Manure in pens, dirty water troughs, mouldy feed in troughs, dirty feeding bags.
- Bio-security: Mixing of chicks from different sources at the feeding pen (sudden exposure to different potential
new sickness-causing organisms).
- Weather: Wind and dust (spreading of organisms and damage to the respiratory resistance of the ostrich. Also the
frost-bite factor that is visible during wet and windy weather.
Watery discharge from the nose, sinuses that swell and sometimes tunicle infection (foamy eyes), feed that sticks to the nose, rattle sounds in the throat and shaking of the head or excessive swallowing.
This spreads to the windpipe, lungs and air sacs.
The oppressing effect creates the opportunity for secondary infections with consequent build-up of pus in the sinuses, air sacs, fever, pneumonia and septic infection.
[Breeding birds often show no signs. Embryo survival, as well as chick quality may be poorer though.]
Control is difficult because of the carrier conditions, concealing tactics of the organisms in the body and limited susceptibility to medication. Therefore, it cannot be eradicated at present; only managed and controlled.
- Early identification and monitoring are important factors.
This determines the type, as well as the duration of treatment.
- Drugs that are effective against mycoplasma are:
Oxyitetracycline, Doxycycline, Chlortetracycline, Tylosin, Lincomycin and Advocin.
- Secondary infections often must be treated with combination drugs. You vet will advise you after having done a complete evaluation.
- Periods of abstention for antibiotics should be adhered to:
Tylosin: 7 days, water-soluble, 3 weeks, feed mixture.
Oxytetracycline: 7days, feed mixture, 30 days, injectable.
Doxycycline: 2 weeks, water-soluble.
Advocin: 7 days, injectable.
Tips for identifying air sac sickness
- Inspect ostriches early morning daily and identify potential signs of early air sac sickness
(foamy eyes, wet or dirty noses, rattle sounds, mucous in water troughs).
- Watch the weather conditions for sudden changes.
- Be aware of feed quality (dusty feed) and compilation for needs. Inspect feeding troughs for signs of mould or presence of old feed.
- Inspect water troughs for signs of mucous contamination and ensure that cleaning procedures are in place.
- Measure mass increase over a 30 day period and compare it to feeding turnover.
- Take note of disapproval of ostriches at the abattoir.
- Take note of autopsy investigation data of farm mortalities.
- Be aware of the effect of stress conditions.
- Reduce stress conditions on the farm.
- Feed according to feeding needs and knowledge thereof.
- Clean feeding pens twice a year.
- Try to control dust and wind (provide cover or wind breaks).
- Reduce population density.
- Let feeding pens rest every 7 years.
- Clean water troughs weekly and feeding troughs daily.
- Use antibiotics judiciously.
- Treat during strategic and high risk times. Let your vet design a programme according to your needs.
- Use individual treatment for individual seriously ill birds or relocate them to an isolated pen.
- If the birds are in a poor condition or feed poorly, you should change to a higher ration.
- Monitor feed intake, mass increase and ribcage/carcass disapprovals.
ITíS A FACT:
- Airway infections are common amongst ostriches.
- Especially manage these risk factors:
- Population density
- Separate chicks from slaughter birds and slaughter birds from breeding birds.
- Do not mix new and old groups. Keep the original groups together.
Source: Dr Adriaan Olivier, technical advisor of the SAOBC