The objective of this study was to describe the cleaning practices currently used for preweaning calves on dairy farms in Quebec, Canada. In addition, contamination of feeding equipment for preweaning calves was described using ATP (expressed as relative light units, RLU), visual assessment, and bacteriological analysis. A questionnaire was administered on 50 commercial dairy farms in Quebec, Canada, regarding the self-reported cleaning protocol used for feeding equipment of preweaning calves. During the visit, a visual score was given to the feeding equipment available at the farm. Afterward, ATP luminometry measurements were obtained using Hygiene UltraSnap and MicroSnap swabs (Hygiene, Camarillo, CA), and the liquid rinsing technique for buckets, nipples, bottles, esophageal tube feeders (ET), the tube of automatic milk feeders (AMF), water samples, and milk replacer. An additional direct swabbing technique was performed on buckets and nipples. The fluid retrieved from the liquid rinsing technique was also used to determine the total bacterial count (TBC) and total coliform count. Based on the bacteriological analysis, optimal RLU cutoff values to determine contamination were obtained. The median (interquartile range) luminometer measurements using the UltraSnap and direct technique for buckets and nipples were 2,082 (348-7,410) and 3,462 (462-7,518) RLU, respectively; and, using the liquid technique for bottles, ET, AMF, water, and milk replacer were 43 (4-974), 15 (4-121), 301 (137-1,323), 190 (71-358), and 94 (38-218) RLU, respectively. Overall, for all equipment and both techniques used, higher RLU values were seen in UltraSnap samples compared with MicroSnap samples. Additionally, for buckets and nipples, higher RLU values were obtained for the direct swabbing method compared with the liquid sampling method for both swabs used. No differences in the level of contamination were seen between the different feeding equipment used within a farm. Overall, a higher correlation with bacteriological results was noticed for ATP luminometry compared with the visual score, with a high correlation for nipples and bottles using the UltraSnap and liquid technique. Based on the classification of "contaminated" (TBC ≥100,000 cfu/mL) or "not contaminated" (TBC <100,000 cfu/mL), optimal ATP luminometer cutoff values for buckets, nipples, bottles, AMF, water, and milk replacer were 798, 388, 469, 282, 1,432, and 93 RLU, respectively. No clear association was found between ATP measurements and the self-reported cleaning protocol. This study gave new insights into the current cleaning procedures and contamination of feeding equipment for preweaning calves on dairy farms in Quebec. In addition, ATP luminometry cutoff values could help benchmark farms regarding cleaning practices and provide customized advice, improving the overall hygiene management, and thus the health, of preweaning calves on dairy farms.
Keywords: ATP bioluminescence; calf; hygiene protocol; milk feeding equipment.
© 2023, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).