Microbiological quality of the water supplied to dairy calves on rural properties

Abstract

The present study was developed to analyze the quality of the water used for watering dairy calves. Water samples were collected from dairy-calf drinkers on 10 farms. The first sample was collected from the non-sanitized drinker; the second, directly from the water supply pipe; the third, after washing and sanitizing the drinker with 2.5% sodium hypochlorite; the fourth, after 15 days of washing and sanitizing the drinker; and the fifth, after 30 days of washing and sanitizing the drinker. Samples were collected in a 1000-mL glass vial with a sterile lid and analyzed for the determination of the most probable number of total coliforms, thermotolerant coliforms and count of mesophilic microorganisms. The presence of mesophiles was detected in all samples. Total and thermotolerant coliforms were found in all samples collected on arrival at the farm and at 15 and 30 days after sanitization. Three farms showed presence of mesophiles in the water collected from the supply network. After washing and sanitizing the drinker, the microorganisms were eliminated. In conclusion, the water supplied to the calves did not exhibit a satisfactory microbiological pattern in the first collection and after 30 days of sanitizing the drinkers. Abrasive cleaning of drinkers, combined with rinsing with chlorine solution, proved to be effective for eliminating mesophilic microorganisms, total coliforms and thermotolerant coliforms.