Winter and poultry diseases
As the cold winter months approach, poultry farmers must prepare to prevent and treat poultry diseases.According to observations, most communal farmers engaged in free-range chicken production systems are prone to face bird mortalities due to diseases during the winter season. For instance, in 2022, farmers experienced higher chicken mortalities between April and August, demonstrating chickens’ susceptibility to disease especially during the winter season.
By definition, a disease is an abnormal condition that negatively affects the structure or functionality of an organism. Poultry diseases are usually a result of either infectious agents such as (bacteria, viruses, or fungi), environmental factors (temperature extremes, poor air quality or injuries from wires) and at times, poor management practices by poultry farmers.
Chickens, ducks, guinea fowl and other birds commonly suffer from either respiratory, neoplastic, or viral diseases. Respiratory diseases usually affect the respiratory system of a bird and examples include infectious coryza and infectious bronchitis. On the other hand, neoplastic diseases cause abnormal growth of tissues in poultry such as Marek’s disease. While viral diseases are caused by agents of minute proportions that invade host cells inside a poultry bird and replicate their DNA material to take over the host cells (fowl pox or infectious bursal disease commonly known as gumboro).
In winter, these diseases become a common occurrence and farmers must be able to identify these diseases by observing their clinical signs and effects on poultry production. Common diseases affecting poultry and their clinical signs are listed below:
Respiratory diseases
Infectious coryza is a respiratory disease that commonly affects chickens, and it is essential to observe the clinical signs depicted by chickens such as sneezing, swelling of eyes with a yellowish discharge, diarrhoea, and retarded growth.
Another disease that affects the respiratory system of poultry is infectious bronchitis. Clinical signs of this disease include symptoms such as gasping when breathing, discharge from eyes, discharge from nostrils, and reduced egg production. In layers, Infectious Bronchitis causes poor eggshell quality, watery albumen, ruffled feathers, and wet droppings. A drop in egg production and weight gain, tracheal rales (small bubbling or rattling sounds in the lungs when inhaling), and urate diarrhoea are also common symptoms.
Infectious bursal disease (gumboro) is a viral disease that shows clinical signs such as trembling, ruffled feathers, poor appetite, dehydration, huddling, vent pecking (the behaviour whereby a chicken pecks the rear end of another chicken, often causing bleeding due to damaged skin and underlying tissue), and depression.
Newcastle disease is a severe, systemic, and fatal viral disease of poultry due to virulent strains of avian paramyxovirus type 1. Its clinical signs depicted by chickens include coughing, sneezing, salivation, drooping wings, paralysis which leads to struggles in movement, twisted necks, and sudden death of poultry birds.
Prevalence
As the winter months draw in, disease prevalence becomes a common trait, and it is during this time that chickens specifically utilise more feed to keep warm and their immunity is compromised.
Diseases can however be minimized through the adoption of good management practices such as instituting bio-security measures around the poultry production zone and ensuring the cleaning and maintenance of hygienic chicken coops to minimize the build-up of infectious agents such as viruses, bacteria, or fungi.
Diseases can further be prevented by introducing a frequent vaccination calendar where the immunisation of poultry becomes a must.
To this end, ND Clone 30 is a water-soluble vaccine that prevents Newcastle disease, IB Ma5 prevents infectious bronchitis, gumboro D78 prevents infectious bursal disease (gumboro) and nobilis coryza is a subcutaneous injectable vaccine.
Finally, farmers must always bolster disease prevention measures during the winter season when the immunity of poultry birds tends to be lower to attain sustainability in their poultry enterprise. If not attended to, diseases can lead to economic losses, and mortality of birds and can result in low egg and meat production which in turn can affect household food security levels. Lastly, take care of your birds so they can make you N$.
* Hanks Saisai is AgriBank’s Technical Advisor: Crops & Poultry.
**Opinion pieces and letters by the public do not necessarily reflect the opinion of the editorial team. The editors reserve the right to abridge original texts. All newspapers of Namibia Media Holdings adhere to the Code of Ethics for Namibian Media, a code established jointly with the Media Ombudsman.