Calf-Level Factors Associated with Bovine Neonatal Pancytopenia – A Multi-Country Case-Control Study

Jones, Bryony A.; Sauter-Louis, Carola; Henning, Joerg; Stoll, Alexander; Nielen, Mirjam; Van Schaik, Gerdien; Smolenaars, Anja; Schouten, Matthijs; den Uijl, Ingrid; Fourichon, Christine; Guatteo, Raphael; Madouasse, Aurélien; Nusinovici, Simon; Deprez, Piet; De Vliegher, Sarne; Laureyns, Jozef; Booth, Richard; Cardwell, Jackie M.; Pfeiffer, Dirk U.

The questionnaire was developed in English, translated into French and German, and field-tested by researchers with experience of BNP cases from the four countries. In the Netherlands and Belgium the English questionnaire was used and the interview conducted in Dutch. There were 91 questions, of which 36 collected descriptive data on calf, dam and sire identification, calf characteristics, clinical signs and laboratory results, and 55 collected data on potential risk factors related to colostrum and milk feeding, dam and sire characteristics, and dam vaccination history. Data were entered into an internet-based form created in Open Source software (Lime-Survey http://www.limesurvey.org/), exported to Microsoft Excel and then to Stata IC 12.1 for coding, cleaning and analysis. Thirty (6 descriptive, 24 potential risk factor) questions were dropped due to a low number of responses or differences in interpretation between countries. Five variables identified the calf, dam and sire. Twenty two variables describing clinical and post-mortem signs and laboratory results were used to define cases and controls. Thirty four variables were used in the statistical analysis and an additional 15 variables were created by recoding, to give a total of 49 exposure variables (3 descriptive and 46 potential risk factor).