title: Prevalence of endemic enteropathogens of calves in New Zealand dairy farms.
abstract: OBJECTIVE
  To conduct a country-wide prevalence study of bovine group A rotavirus, coronavirus, Cryptosporidium parvum, Salmonella spp. and enterotoxigenic K99(+) Escherichia coli (K99) in calves on New Zealand dairy farms.
  
  
  METHODS
  Faecal samples (n=1,283) were collected during the 2011 calving season from calves that were 1-5 and 9-21 days-old on 97 dairy farms, and were analysed for the presence of bovine group A rotavirus, coronavirus, Cryptosporidium and Salmonella spp., and K99. Farm-level prevalences were calculated and relationships between demographic variables and the presence of enteropathogens were examined using logistic regression models.
  
  
  RESULTS
  Of the 97 farms, 93 (96%) had at least one sample infected with enteropathogens. The standardised farm prevalences of bovine group A rotavirus, bovine coronavirus and C. parvum were 46, 14 and 18%, respectively, in calves that were 1-5 days-old, and 57, 31 and 52%, respectively, in calves that were 9-21 days-old. The farm-level prevalence of K99 was 11% in calves that were 1-5 days-old. Salmonella spp. were found in three and four samples, from calves that were 1-5 and 9-21 days-old, respectively. No associations between explanatory variables and the presence of the enteropathogens were identified at the farm level. At the calf level, the odds of C. parvum shedding and of co-infection with any combination of pathogens were greater in calves that were 9-21 than 1-5 days-old.
  
  
  CONCLUSIONS
  This study provides epidemiological estimates of the prevalence of calves' enteropathogens in New Zealand, which could be used for infection risk assessment or estimation of the environmental loads of pathogens shed in cattle faeces.
authors.affiliation: a mEpiLab, Infectious Disease Research Centre , Massey University , Private Bag 11222, Palmerston North , New Zealand.
authors.forename: J
authors.initials: J
authors.lastname: Al Mawly
authors.forename: A
authors.initials: A
authors.lastname: Grinberg
authors.forename: D
authors.initials: D
authors.lastname: Prattley
authors.forename: J
authors.initials: J
authors.lastname: Moffat
authors.forename: N
authors.initials: N
authors.lastname: French
mesh_terms: D000375:Aging; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology*; D003612:Dairying; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence
keywords: Calf diarrhoea; Cryptosporidium; K99; Salmonella; coronavirus; prevalence; rotavirus