The quality of drinking water is important for broiler health and welfare. Contamination of the water supply systems with pathogenic organisms may result in zoonosis and epizootics. Jeffery Ho, City University of Hong Kong, and colleagues investigated the bacterial burden of nipple watering systems in emptied broiler houses between flocks.

During a presentation at the 2022 World’s Poultry Congress, Ho said that 24 out of 29 broiler farms, representing 83% of all licensed premises in Hong Kong, participated in this study.

Water samples were collected from drinking nipples at proximal, medial, and distal positions to the reservoir tanks at the finishing period of a flock (T1) and immediately before the introduction of a new flock (T2). The houses remained empty for seven days between flocks T1 and T2. Total bacterial count (TBC) and total coliform count (TCC) were determined. At T1, the ventilator blades of poultry houses were additionally sampled. Tracheal swabs were collected from finisher broilers, he said.

At T1, both the median TBC and TCC were less than 1 colony-forming unit (CFU) and 987 CFU per mL, which were acceptable according to the American Public Health Association guideline, said Ho.

Immediately before introducing a new flock, the bacterial load of TBC and TCC increased by four-fold (t=-3.207, P=0.003). Tracheal colonization of finisher broilers with Escherichia coli was associated with an increased risk for isolating the organism from the ventilator blades (Odds ratio=3.2, 95% CI 1.6-8.7), according to the researchers.

The ventilators and nipple waterers are reservoirs for coliforms. Prolonged static water flow of the drinking pipe systems during the downtime may have contributed to the overgrowth of aerobic bacteria, he noted.

Water quality of nipple systems should be monitored at the end of the emptying phase. Increasing the water flow for a few hours before introducing a new flock is advised, Ho concluded.