The incidence of milk leakage (ML) after dry-off (DO) and related risk factors was studied in 1,175 dairy cows from 41 commercial herds in 8 European countries: Belgium, Czech Republic, Denmark, France, Germany, Italy, the Netherlands, and Spain. Milk leakage was assessed twice for 30 s each during 3 visits at 20 to 24 h, 30 to 34 h, and 48 to 52 h after DO. Information related to dry-cow management and udder health was collected at herd and cow level, including individual somatic cell count (ISCC) from test-day controls and occurrence of clinical mastitis cases from DO until 30 d in lactation. Mixed-effect logistic regression analyses were used to identify possible risk factors for ML and to study the association between ML and new intramammary infections. Intramammary infections were defined as clinical mastitis cases during the dry period and in the first 30 d in lactation or a rise in ISCC from before to after the dry period (threshold: 200,000 cells/mL) or both. Milk leakage was observed in 24.5% of the cows between 20 and 52 h after DO, where the herd incidence varied between 0.0 and 77.8%. The reduction in number of milkings in the weeks before DO had statistically significant effect on the ML incidence. When the milking frequency was reduced from 3 times/d to 2 or maintained at twice a day, cows had 11 (95% CI = 3.43-35.46) or 9 (95% CI = 1.85-48.22) times higher odds of leaking milk, respectively, compared with cows where the milking frequency was reduced from twice to once a day. Also, the milk production 24 h before DO was associated with ML incidence. Hence, cows with a milk production between 13 and 21 L or above 21 L had 2.3 (95% CI = 1.48-3.53) and 3.1 (95% CI = 1.79-5.3) times higher odds of leaking milk, respectively, compared with cows with a milk production below 13 L. A higher ML incidence was present in the group of cows with an average ISCC in the last 3 mo before DO ≥200,000 cells/mL (odds ratio = 1.7; 95% CI = 1.13-2.41) compared with cows with an average ISCC <100,000 cells/mL. Quarters with ML tended to have 2.0 times higher odds of developing clinical mastitis compared with quarters not leaking milk. Cows with ML tended to have 1.5 times higher odds of intramammary infections (i.e., an increase of ISCC or clinical mastitis) compared with cows without ML.

CEVA Santé Animale Avenue de la Ballastière 33500 Libourne France

Clinique Vétérinaire LesVet 3 Place du Champ de Bataille 29260 Lesneven France

Department of Farm Animal Health Utrecht University Yalelaan 7 Utrecht 3584 CL the Netherlands

Department of Veterinary and Animal Sciences University of Copenhagen Grønnegårdsvej 2 1870 Frederiksberg C Denmark

Embryo Vet Studio Veterinario Cascina Bosco 6 25028 Verdanuova Italy

Faculty 2 University of Applied Sciences and Arts Department of Bioprocess Engineering Heisterbergallee 10A 30453 Hannover Germany

FarmVet spol s r o Rojšín 5 38203 Brloh Czech Republic

GD Animal Health PO Box 9 7400 AA Deventer the Netherlands

Italian National Reference Centre for Animal Welfare Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna Bruno Ubertini Via A Bianchi 9 25124 Brescia Italy

M team and Mastitis and Milk Quality Research Unit Faculty of Veterinary Medicine Ghent University Salisburylaan 133 B 9820 Merelbeke Belgium

Réseau Cristal SELAS EVA Argentonnay 79150 France

Servet Talavera S L Plaza San Andrés 15 45600 Talavera de la Reina Toledo Spain

Van Reen Cattle Veterinarian et Dierenartsenpraktijk Flevoland Gildenveld 76 3892 DJ Zeewolde the Netherlands

References provided by Crossref.org