• Anaïs Chancy, Département des Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal
• Débora E. Santschi, Lactanet, Sainte-Anne-de-Bellevue
• Éric Paquet, Département des Sciences Animales, Université Laval
• David Renaud, Department of Population Medicine, University of Guelph
• Édith Charbonneau, Département des Sciences Animales, Université Laval
• Mike Steele, Department of Population Medicine, University of Guelph
• Nicolas Barbeau-Grégoire, Département des Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal
• Laura Van Driessche, Département des Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal
• Sébastien Buczinski, Département des Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal

The objective of this observational study was to standardize a reliable and repeatable technique using ATP luminometry to describe the cleanliness of various feeding equipment used for pre-weaning calves in dairy farms. A total of 7 Québec commercial dairy herds were selected. Following visual hygiene scoring, the cleanliness of every available feeding equipment was assessed using a direct surface swabbing for buckets and nipples with Hygiena UltraSnap swabs. A liquid rinsing technique was realized for esophageal feeders, bottles, and automatic milk feeders (AMF) with UltraSnap, AquaSnap, and MicroSnap swabs. Both intra- and inter-operator phases were performed to validate the technique, as well as a comparison with conventional bacterial culture. A total of 519 swab samples were obtained from 201 equipment. The median (interquartile range) contamination in RLU for a bottle, esophageal feeder, AMF, bucket and nipple was 2 (1;6), 2 (0;12), 52 (19;269), 886 (128;7,230) and 899 (142;6,928), respectively. The direct technique selected after the intra-operator phase showed an excellent correlation of the intra-rater reliability (intra-class correlation (ICC) = 0.93; 95% CI : 0.88 – 0.96). The inter-operator phase (2 sessions with 3 different operators) demonstrated a good reliability too. Luminometer values were positively associated with the visual score of esophageal feeders, AMF and buckets (P<0.05). A positive correlation between bacterial culture and direct swabbing of buckets was also found. This study describes a standardized and practical on-farm technique for assessing the hygienic status of feeding equipment by luminometry, which can be integrated in the management of pre-weaning dairy calves.