title: Is lack of antibiotic usage affecting udder health status of organic dairy cattle?
abstract: This research communication aimed to compare somatic cell count (SCC), the main marker of udder health status, in organic farms not using antibiotics (O, n = 6), organic farms using antibiotics (OA, n = 7) and conventional farms (CA, n = 5) using antibiotic treatments, all of them at pasture. SCC was statistically significantly higher in O (173780) compared to CA (93325) and OA (107152). Milk yield had a significant diluting effect on SCC and differences between groups increased with parities. Stratified analysis of SCC depending on lactation number and % of monthly SCC test with different linear scores (LS) indicated that there is no difference in udder health in the primiparous heifers from the three groups of farms, but it deteriorates in older cows because of chronic infections in O (possibly due to lack of antibiotic use). Our results suggest that the non-use of antibiotics had an effect in udder health leading to higher occurrence of clinical and subclinical mastitis. Therefore, preventive management practices for mastitis control are essential in organic farms.
authors.affiliation: Departamento de Anatomía, Produción Animal e Ciencias Clínicas Veterinarias,Facultad de Veterinaria,Universidade de Santiago de Compostela,27002 Lugo,Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Orjales
authors.affiliation: Departamento de Patoloxía Animal,Facultad de Veterinaria,Universidade de Santiago de Compostela,27002 Lugo,Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: López-Alonso
authors.affiliation: Departamento de Patoloxía Animal,Facultad de Veterinaria,Universidade de Santiago de Compostela,27002 Lugo,Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Rodríguez-Bermúdez
authors.affiliation: Departamento de Patoloxía Animal,Facultad de Veterinaria,Universidade de Santiago de Compostela,27002 Lugo,Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Rey-Crespo
authors.affiliation: Centro de Investigación y Formación Agrarias (CIFA),Héroes 2 de mayo 27,39600 Muriedas,Cantabria,Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Villar
authors.affiliation: Departamento de Anatomía, Produción Animal e Ciencias Clínicas Veterinarias,Facultad de Veterinaria,Universidade de Santiago de Compostela,27002 Lugo,Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Miranda
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D002417:Cattle; D002452:Cell Count; D003612:Dairying / Q000379:methods*; D005260:Female; D006304:Health Status; D008321:Mammary Glands, Animal / Q000503:physiopathology*; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000503:physiopathology / Q000517:prevention & control*; D008892:Milk / Q000166:cytology; D058871:Organic Agriculture
chemical_list: D000900:Anti-Bacterial Agents
keywords: Udder health; antibiotics; organic farming; somatic cell count