PSXIV-2 - Effect of Drinking Water Disinfection Treatments on Water Quality, Water and Feed Consumption, Apparent Total Tract Digestibility and Health in Holstein Bulls Fed High-concentrate Diets

Abstract: The aim of this study was to evaluate the effect of different drinking water disinfection treatments on water quality, water and feed consumption, apparent total tract digestibility, and animal health in fattening Holstein bulls. Bulls (n=24; 176 ± 16.3 kg BW, and 149 ± 5.8 d age) were housed individually and fed ad libitum. Animals were assigned to 1 of 4 drinking water disinfection treatments: 1) CTR (n=6), no treatment; 2) ACCHL (n=6), acidification (0.65 mL/L phosphoric acid) and chlorination (0.15 mL/L sodium hypochlorite); 3) PER (n=6), 0.15 mL/L peroxide, and 4) DIO (n=6), 2.50 mL/L chlorine dioxide. Water consumption and animal health status was recorded daily. Water disinfectant capacity were analyzed weekly. Feed consumption was recorded every 2 wk. Water quality was analyzed every 4 wk. At d 0, 42, 112 and 210 blood samples were collected. At d 35 and 140 apparent total tract digestibility was estimated. Data were analyzed with a mixed effects model. Means water disinfectant capacity were pH 6.60 and 0.75 mg/L free residual chlorine in ACCHL, 10.6 mg/L peroxide in PER, and 0.52 mg/L chlorine dioxide in DIO. Water treatments did not affect physicochemical water quality; however, they reduced (P< 0.01) water total coliforms count compared with CTR, and ACCHL and DIO were lesser than PER (199, 0, 35, and 0 ± 0.2 UFC/100mL for CTR, ACCHL, PER, and DIO, respectively). Dry matter intake tended (P=0.06) to increase in DIO compared with CTR (8.24 vs. 7.49 ± 0.266 kg/d, respectively). Water treatments did not affect nutrient digestibility nor blood parameters. In conclusion, drinking water disinfection treatments tested had a good disinfectant efficacy without detrimental effect on health and nutrient digestibility in bulls fed high-concentrate diets. Further commercial studies with more animals are needed to evaluate the potential effect of chlorine dioxide on intake and efficiency.