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

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

Observational study on variation of longitudinal platelet counts in calves over the first 14 days of life and reference intervals from cross-sectional platelet and leukocyte counts in dairy calves up to two months of age

Platelet and leukocyte count reference intervals (RIs) for cattle differ by age and while adult RIs are known, RIs for calves are studied less. The aims of this observational study are to evaluate variation of platelet counts of Holstein Friesian calves over the first 14 days of life and to propose RIs for platelet and leukocyte counts of Holstein Friesian calves aged 0–60 days. In a longitudinal study, 19 calves were blood sampled 17 times, in the first 14 days of their lives. Blood was collected in a citrate blood tube and platelet counts were determined. We assessed the course of platelet counts. In a field study, 457 healthy calves were blood sampled once. Blood was collected in an EDTA blood tube and platelet and leukocyte counts were determined. The RIs were calculated by the 2.5 and 97.5 percentiles. Platelet counts started to increase 24 h after birth (mean platelet count 381 × 109/L ± 138 × 109/L) and stabilized after five days (mean platelet count 642 × 109/L ± 265 × 109/L). In calves up to six days of age, platelet counts were lower than in calves older than five days. In conclusion, the RIs of platelet and leukocyte counts in calves were wider in range than the RIs for adult cattle, therefore, calf specific RIs for platelet and leukocyte counts should be used. From 6 until 60 days of age, we propose an RI for platelet counts of 287–1372 × 109/L and for the first 60 days of life an RI for leukocyte counts of 4.0–18.9 × 109/L

Observational study on variation of longitudinal platelet counts in calves over the first 14 days of life and reference intervals from cross-sectional platelet and leukocyte counts in dairy calves up to two months of age

Platelet and leukocyte count reference intervals (RIs) for cattle differ by age and while adult RIs are known, RIs for calves are studied less. The aims of this observational study are to evaluate variation of platelet counts of Holstein Friesian calves over the first 14 days of life and to propose RIs for platelet and leukocyte counts of Holstein Friesian calves aged 0–60 days. In a longitudinal study, 19 calves were blood sampled 17 times, in the first 14 days of their lives. Blood was collected in a citrate blood tube and platelet counts were determined. We assessed the course of platelet counts. In a field study, 457 healthy calves were blood sampled once. Blood was collected in an EDTA blood tube and platelet and leukocyte counts were determined. The RIs were calculated by the 2.5 and 97.5 percentiles. Platelet counts started to increase 24 h after birth (mean platelet count 381 × 109/L ± 138 × 109/L) and stabilized after five days (mean platelet count 642 × 109/L ± 265 × 109/L). In calves up to six days of age, platelet counts were lower than in calves older than five days. In conclusion, the RIs of platelet and leukocyte counts in calves were wider in range than the RIs for adult cattle, therefore, calf specific RIs for platelet and leukocyte counts should be used. From 6 until 60 days of age, we propose an RI for platelet counts of 287–1372 × 109/L and for the first 60 days of life an RI for leukocyte counts of 4.0–18.9 × 109/L

Results of univariable analysis of dam vaccination variables showing variables with p<0.02 (n = 1296).

<p>Results of univariable analysis of dam vaccination variables showing variables with p<0.02 (n = 1296).</p

Results of multivariable model (n = 1296); conditional logistic regression model with farm as matching variable.

<p>Exposure variables are dam PregSure vaccination, lactation number, colostrum from different cow(s) and raw milk from dam only. Interactions were included between dam PregSure vaccination and lactation number, and between dam PregSure vaccination and colostrum from different cow(s). The interaction terms have been multiplied with the baseline odds ratios to obtain odds ratios for each variable category above baseline.</p

Distribution of case and control farms using different BVDV vaccines in multi-country BNP study (n = 1165).

<p>Distribution of case and control farms using different BVDV vaccines in multi-country BNP study (n = 1165).</p

Numbers of confirmed matched case and control calves per country.

<p>Numbers of confirmed matched case and control calves per country.</p

Production type of farms included in multi-country BNP case control study.

<p>Production type of farms included in multi-country BNP case control study.</p

Results of multivariable conditional logistic regression analysis for each of five risk factor groups for a multi-country BNP case-control study.

<p>Results of multivariable conditional logistic regression analysis for each of five risk factor groups for a multi-country BNP case-control study.</p

Results of univariable analysis of dam and sire characteristics showing variables with p<0.02 (n = 1296).

*<p>Brown Swiss, Limousin, Limpurger, Pinzgau, Charolais, MRIJ, Montbéliarde, Abondance, Scandinavian Roodbont, Aubrac, Angus, Blanc Bleu, Maine Anjou, Normande, Prog Federat Eur Pie, Blonde d’Aquitaine, Aure et St Girons Ca.</p