Herd-level animal management factors associated with the occurrence of bovine neonatal pancytopenia in calves in a multi-country study

Abstract

Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named ‘bovine neonatal pancytopenia’ (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in four BNP affected countries (Belgium, France, Germany and the Netherlands) to identify herd management risk factors for BNP occurrence. Data were collected using structured face-to-face and telephone interviews of farm managers and their local veterinarians. In total, 363 case farms and 887 control farms were included in a matched multivariable conditional logistic regression analysis. Case-control status was strongly associated with the odds of herd level use of the vaccine PregSure® BVD (PregSure, Pfizer Animal Health) (matched adjusted odds ratio (OR) 107.2; 95% CI: 41.0–280.1). This was also the case for the practices of feeding calves colostrum from the calf’s own dam (OR 2.0; 95% CI: 1.1–3.4) or feeding pooled colostrum (OR 4.1; 95% CI: 1.9–8.8). Given that the study had relatively high statistical power and represented a variety of cattle production and husbandry systems, it can be concluded with some confidence that no other herd level management factors are competent causes for a sufficient cause of BNP occurrence on herd level. It is suggested that genetic characteristics of the dams and BNP calves should be the focus of further investigations aimed at identifying the currently missing component causes that together with PregSure vaccination and colostrum feeding represent a sufficient cause for occurrence of BNP in calves.

Spatial distribution and incidence of bovine neonatal pancytopenia in Bavaria, Germany

“…Retrospectively, it cannot be clarified if the signs observed in 2000 were unrelated to BNP [39]. Alternatively, this could have been a case of haemorrhagic diathesis of unrelated aetiology, as seen in other studies [16,22]. Such idiopathic cases have been described by Stoll et al (2016) prior to the first description of Preg-Sure®BVD related BNP.…”

“…In the meantime, the occurrence of BNP has been linked to the use of an inactivated vaccine against bovine viral diarrhoea virus (BVDV) (PregSure®BVD, then Pfizer Animal Health, now Zoetis, Berlin, Germany) [16][17][18][19][20][21][22]. In the production of this vaccine, antigens from the permanent bovine kidney cell line, used for the replication of the virus, were contained in the vaccine and caused the production of alloantibodies (antibodies against nonself antigens from members of the same species) in some cows after vaccination [17,23].…”

Three cases of alloimmune mediated pancytopenia in calves resembling bovine neonatal pancytopenia

“…Variability in severity could be explained by differences in the quantity of ingested alloantibodies, genetics of dam, sire and calf and the lag time between birth and ingestion of colostrum [ 18 , 21 ]. The causal role of a bovine viral diarrhea virus vaccine (PregSure® BVD, Pfizer Animal Health, Berlin, Germany) in BNP was evidenced [ 2 , 4 , 13 , 22 – 26 ]. The adjuvanted vaccine induced the production of alloantibodies in some vaccinated cattle depending on their genotype of bovine major histocompatibility complex class I [ 2 , 4 , 21 – 25 , 27 – 29 ].…”