An evaluation of pathogens and risk factors associated with neonatal enteritis in calves. Reynolds, M.W., BVM&S DCHP MRCVS Livestock Veterinary Teaching and Research Unit, Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, 410 Werombi Rd, Camden, NSW, 2570. Objectives; 1). An evaluation of the cumulative incidence of neonatal enteritis (based on farmer treatment records), associated cumulative mortality (based on British Cattle Movement Services data) and pathogens associated with neonatal enteritis, on a subset of practice farms. 2). An examination of risk factors associated with the cumulative incidence of neonatal enteritis and its associated cumulative mortality, on a subset of practice farms. Analysis of BCMS data showed a significant association between those herds utilizing dedicated youngstock staffing and a reduced neonatal calf cumulative mortality within the first twenty one days of life (RR= 2.5, 95% CI= 1.25 to 5.01, p=0.001 Fishers Exact test). (Figure 4). Figure 4. Neonatal calf cumulative mortality from BCMS data relative to the presence (BLUE BARS) or absence (RED BARS) of dedicated youngstock staff. Analysis of BCMS data showed a significant association between the presence of circulating BVD virus and an increased neonatal calf cumulative mortality within the first twenty one days of life (RR= 0.30, 95% CI= 0.08 to 1.13, p=0.04 Fishers Exact Test). (Figure 5). Figure 5. Neonatal calf cumulative mortality from BCMS relative to the absence (BLUE BARS), presence (RED BARS) of circulating BVDV or those herds with an inconclusive result (YELLOW BARS). Materials and Methods; 47 dairy and beef farms, with a UK wide distribution and from a single Veterinary practice contributed data to the study. Information on calf management practices and client perception of the incidence of neonatal enteritis and mortality within the first three weeks of life, were gathered in a quantitative fashion, through the development and distribution of a questionnaire. Client perception of the incidence of neonatal enteritis and neonatal calf mortality within the first three weeks of life was then paired against actual disease incidence and mortality rates on farm. Surveillance for enteric pathogens was undertaken when a diagnosis of neonatal enteritis was made by the attending veterinarian, either during routine calf health monitoring or sick calf visits, utilizing the validated “Cow-side ELISA” Scour Check Rapid™ (MSD Animal Health), to test for a fixed group of major pathogens associated with neonatal enteritis. Results; Mean neonatal enteritis cumulative incidence was 26% (95% CI=18.11 to 33.89) and mean cumulative mortality was 4.5% (95% CI= 2.65 to 6.35) across the studied farms. Farmer perception bore no relationship to the actual cumulative incidence of neonatal enteritis experienced on farm (Pearson Correlation Coefficient, r= 0.01 P= 0.96). (Figure 1.) Figure 1. Farmer perception of neonatal enteritis cumulative incidence compared to cumulative incidence determined from farmer treatment records. Rotavirus was the most prevalent pathogen identified, with 70% of calves showing exposure (n=35). Cryptosporidium parvum was the second most commonly encountered pathogen accounting for 40% of infections (n=20). Of the calves sampled, 40% had combined Rotavirus and Cyyptosporidium parvum infections (n=20). Figure 2. Diagnostic sample results for studied calves. Analysis of BCMS data revealed a significant association in terms of higher neonatal calf cumulative mortality in the first twenty one days of life in those herds relying on self feeding from dam, compared to those actively administering colostrum to newborn animals (RR= 2.83, 95% CI= 1.01 to 7.91, p=0.045 Fishers Exact test).(Figure 3). Figure 3. Neonatal calf cumulative mortality from BCMS data relative to actively feeding colostrum (BLUE BARS) or relying on self-feeding from dam (RED BARS). . Conclusions; Reliance upon self feeding from the dam as the sole means of passive transfer, the employment of dedicated youngstock staff and the presence of endemic Bovine Viral Diarrhoea Virus (BVDV), were found to have a significant association with neonatal calf mortality in the first twenty one days of life. These factors compounded by the finding that farmer perception bore NO relationship to the actual cumulative incidence of neonatal enteritis experienced on farm may warrant further investigation using a larger dataset and may serve as factors for consideration in future youngstock health audits and knowledge transfer programs. Acknowledgements; The author wishes to thank Dr. Alastair Macrae MRCVS, Dr. Ian Handel MRCVS, Dr. Ian Nanjiani MRCVS and the staff and clients of Westpoint Veterinary Services (Cumbria) LLP and Westpoint Veterinary Services (Dumfries) LLP for their assistance in this study