Inflammatory process, also known as cellulitis, coliform cellulitis and infectious process, is a condition in broilers characterized by a diffuse subcutaneous cellulitis and subsequent infection of the fascia overlying the breast, legs and ventral body cavity and frequently extending to the inguinal region.
Most carcasses with some degree of cellulitis have to be reprocessed to be trimmed further, which makes it one of the major causes of carcass downgrading and plant condemnations resulting in significant economic losses.
Inflammatory process condemnations at the processing plant are mainly due to skin cuts caused by toe scrapes which have become infected by Escherichia coli. Although other types of bacteria have been isolated out of cellulitis lesions, E. coli is clearly the bacteria associated with the feature lesion of inflammatory process and is the reason why the condition is also referred to as coliform cellulitis.
Cellulitis prevention and control
There is no a magic solution for preventing inflammatory process or cellulitis in broilers. It is a condition caused by multiple management factors that make the birds excited and scratch. However, carefully addressing these practices can help to prevent scratches and their development into lesions.
1. Reduce bacterial load through proper cleaning, downtime and windrowing
The longer the downtime, the lower the inflammatory process incidence. However, the success of such a program requires a complete clean-out, and disinfection as E .coli isolates from affected flocks have been found to persist in the broiler house for long periods, affecting consecutive flocks.
Windrowing the litter in the middle of the house to heat the entire pile has been shown to reduce E. coli numbers as long as the heat generated is high enough. From the pathogen reduction standpoint, the goal is to reach 130F (55C) sustained for a minimum of three to four days. It is critical that adequate time be devoted to “cooling down” and drying out the litter.
2. Stocking density
There is a clear correlation between the number of birds placed in the house and the incidence of skin scratches and inflammatory process.
In some instances, bird density is driven by chicken meat sales, so it is not uncommon to see complexes with higher inflammatory process incidence during the months where sales are up. In these cases, it is simply the result of the increase in stocking density that raises incidence, but also the failure to add the equipment needed for the extra birds placed in the house.
3. Dim the lights after the first week of age
Once the birds reach their expected seven-day body weight target, it is advisable to lower the light intensity to about 10 lux (1 foot candle) to reduce bird activity and prevent stress.
Once the lights are dimmed, they should not be spiked up by personnel coming into the house. A drastic increase in light intensity is a bad practice in the industry, as it brings high levels of excitability and stress to the birds, leading to skin scratches.
4. As the birds age, reduce the number of walk-throughs and slow the pace
Walk through the house slowly to minimize bird crowding and pile-ups.
Walking through the houses at a fast pace scares the birds, making them crawl over each other, leading to toe scrapes and skin damage.
Reduce the number of walk-throughs during the last five days of the cycle and walk through the house slower than ever.
5. Keep birds evenly distributed throughout the house
Whole-house brooding helps prevent inflammatory process as the birds do not tend to go back to the brooding area.
Some companies install migration barriers when they place the chicks, to help ensure that chicks can be counted and placed evenly in the house.
Migration fences should be placed in a diagonal form, leaving an angle with the wall at about 30 degrees to prevent piling in the corners while walking the house.
6. Maintain proper environmental temperatures to prevent crowding and scratching
The quality of the environment inside the broiler house plays an important role, not only in performance and health, but on carcass quality.
Adequate temperatures and air quality throughout the house really help control moisture levels and maintain good litter quality.
Warm litter temperatures during winter months and proper air speed through the birds in the summer months are critical to prevent crowding and scratching.
7. Avoid feed restrictions or feed outages
The act of refilling feed pans may result in high bird competition to reach the feed, causing overcrowding and scratching.
8. Proper set-up for catching
During catching, lighting should be kept dimmed.
Catching crews must understand that the calmer the whole catching process is, the lower the stress, the number of dead on arrivals and plant condemnations. Bird density in the crates must be reduced in the summer months.
9. Skin integrity - vitamin E, zinc supplementation
The importance of zinc and vitamin E in maintaining and improving skin integrity has been well proven.
Skin is the first line of defense against bacterial infection, and skin damage is the main portal of entry and primary insult for cellulitis.
Recent studies have showed that broilers fed complexed zinc had decreased skin tears and scratches, resulting in fewer incidents and severity of cellulitis, compared to birds fed inorganic zinc sulphate.
The appearance of cellulitis lesions makes it easy for inspectors, producers and veterinarians to recognize the condition, which helps when assessing the results of prevention strategies.