Calf-level factors associated with bovine neonatal pancytopenia - a multi-country case-control study

Bovine neonatal pancytopenia (BNP), a high fatality condition causing haemorrhages in calves aged less than 4 weeks, was first reported in 2007 in Germany and subsequently observed at low incidence in other European countries and New Zealand. A multi-country matched case-control study was conducted in 2011 to identify calf-level risk factors for BNP. 405 BNP cases were recruited from 330 farms in Belgium, France, Germany and the Netherlands by laboratory confirmation of farmer-reported cases. Up to four calves of similar age from the same farm were selected as controls (1154 calves). Risk factor data were collected by questionnaire. Multivariable modelling using conditional logistic regression indicated that Preg Sure HBVD (Preg Sure, Pfizer Animal Health) vaccination of the dam was strongly associated with BNP cases (adjusted matched Odds Ratio - am OR 17.8 first lactation dams; 95% confidence interval - ci 2.4, 134.4; p = 0.005), and second or more lactation Preg Sure-vaccinated dams were more likely to have a case than first lactation vaccinated dams (am OR 2.2 second lactation; ci 1.1, 4.3; p = 0.024; am OR 5.3 third or more lactation; ci 2.9, 9.8; p