Mortality is the percentage of deaths present on a farm. An increase in mortality, particularly if it happens suddenly, is a major cause of alarm. It has a major impact on the performance of broilers and laying hens, and also on the profitability of the farm.
What is a “normal” mortality pattern?
Mortality is defined as the incidence of deaths. Mortality usually peaks in the first week and then declines. In general, a mortality rate of 0,1% per day can be defined as a significant increase of deaths. A mortality rate of 0,5% per day is a dramatic increase of deaths.
Mortality in broilers
In broilers, mortality is usually higher in the first week. The mortality rate in broilers peaks after approximately 3 to 4 days after hatching, and should not be higher than 0,5% per day. After the peak, mortality decreases and should stabilize at around 10 days of life, and should be lower than 0,05% per day, before increasing slowly around the 31 days of age.
Mortality in laying hens
In laying hens, a mortality rate of 0,5% during the first week is normal. The total mortality rate during the rearing period (first 17 weeks) should not be more than 2%.
What are the most common causes of mortality?
High deaths can have an infectious causes, such as:
· Newcastle disease;
· Gumboro disease;
· Necrotic enteritis;
· Salmonella and many more.
There are also non-infectious causes, such as:
· power failure;
· ventilation failure;
· heat stress;
· carbon monoxide poisoning;
· fright reaction;
· feed disruptions;
How to identify cause of high mortality
As mentioned previously, a sudden increase in mortality can have many causes. In order to identify the cause for a sudden increase in mortality, it is important to see if any conditions have changed over time (for example feces quality, temperature, source of water, etc.). To identify these changes, it is important to consistently keep records of the poultry houses. Practicing record keeping provides valuable information that is stored over time. Once problems occur, such as high mortality, you will possess more information to help identify the possible causes of the problems. For more information on record keeping and how to practice it, click here.
Prevention is better than cure
An increase in mortality results in significant financial losses. Therefore, prevention is better than cure. Preventive measures, such as biosecurity measures are key.