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Evidence of a high incidence of subclinically affected calves in a herd of cattle with fatal cases of Bovine Neonatal Pancytopenia (BNP).

Bell CR, Kerr MG, Scott PR, Morrison WI, Brown H - BMC Vet. Res. (2014)

Bottom Line: Together with clinical BNP cases, this gave the study farm a BNP incidence of 18%.Calves with BNP were found to be distributed throughout the calving period, with no clustering, and no significant differences in the date of birth of cases or subclinical cases were found compared to the rest of the calves.Subclinical BNP was found to occur at a high incidence in a herd of cattle with fatal cases of BNP.

View Article: PubMed Central - PubMed

Affiliation: The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh EH25 9RG, Scotland, UK. lottie.bell@ed.ac.uk.

ABSTRACT

Background: Bovine Neonatal Pancytopenia (BNP) is a disease of calves characterised by bone marrow trilineage hypoplasia, mediated by ingestion of alloantibodies in colostrum. Suspected subclinical forms of BNP have been reported, suggesting that observed clinical cases may not represent the full extent of the disease. However to date there are no objective data available on the incidence of subclinical disease or its temporal distribution. This study aimed to 1) ascertain whether subclinical BNP occurs and, if so, to determine the incidence on an affected farm and 2) determine whether there is evidence of temporal clustering of BNP cases on this farm. To achieve these aims, haematological screening of calves born on the farm during one calving season was carried out, utilising blood samples collected at defined ages. These data were then analysed in comparison to data from both known BNP-free control animals and histopathologically confirmed BNP cases. An ordinal logistic regression model was used to create a composite haematology score to predict the probabilities of calves being normal, based on their haematology measurements at 10-14 days old.

Results: This study revealed that 15% (21 of 139) of the clinically normal calves on this farm had profoundly abnormal haematology (<5% chance of being normal) and could be defined as affected by subclinical BNP. Together with clinical BNP cases, this gave the study farm a BNP incidence of 18%. Calves with BNP were found to be distributed throughout the calving period, with no clustering, and no significant differences in the date of birth of cases or subclinical cases were found compared to the rest of the calves. This study did not find any evidence of increased mortality or increased time from birth to sale in subclinical BNP calves but, as the study only involved a single farm and adverse effects may be determined by other inter-current diseases it remains possible that subclinical BNP has a detrimental impact on the health and productivity of calves under certain circumstances.

Conclusions: Subclinical BNP was found to occur at a high incidence in a herd of cattle with fatal cases of BNP.

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Related in: MedlinePlus

Frequency of calves with different composite haematology scores (rounded to integer values). Calves with no clinical signs of BNP (group 1) – grey columns, BNP cases (group 2) - black columns, normal calves (group 3) - white columns. Calves with a composite haematology score of <11.68 are predicted to have a less than 5% chance of being normal.
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Fig1: Frequency of calves with different composite haematology scores (rounded to integer values). Calves with no clinical signs of BNP (group 1) – grey columns, BNP cases (group 2) - black columns, normal calves (group 3) - white columns. Calves with a composite haematology score of <11.68 are predicted to have a less than 5% chance of being normal.

Mentions: Overall the composite haematology scores for calves in the BNP-affected herd (group 1) were significantly lower (p < 0.001) than that of the normal calves (group 3) (t-test). The distributions of composite haematology scores for groups 1, 2 and 3 are shown in Figure 1.Figure 1


Evidence of a high incidence of subclinically affected calves in a herd of cattle with fatal cases of Bovine Neonatal Pancytopenia (BNP).

Bell CR, Kerr MG, Scott PR, Morrison WI, Brown H - BMC Vet. Res. (2014)

Frequency of calves with different composite haematology scores (rounded to integer values). Calves with no clinical signs of BNP (group 1) – grey columns, BNP cases (group 2) - black columns, normal calves (group 3) - white columns. Calves with a composite haematology score of <11.68 are predicted to have a less than 5% chance of being normal.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4216910&req=5

Fig1: Frequency of calves with different composite haematology scores (rounded to integer values). Calves with no clinical signs of BNP (group 1) – grey columns, BNP cases (group 2) - black columns, normal calves (group 3) - white columns. Calves with a composite haematology score of <11.68 are predicted to have a less than 5% chance of being normal.
Mentions: Overall the composite haematology scores for calves in the BNP-affected herd (group 1) were significantly lower (p < 0.001) than that of the normal calves (group 3) (t-test). The distributions of composite haematology scores for groups 1, 2 and 3 are shown in Figure 1.Figure 1

Bottom Line: Together with clinical BNP cases, this gave the study farm a BNP incidence of 18%.Calves with BNP were found to be distributed throughout the calving period, with no clustering, and no significant differences in the date of birth of cases or subclinical cases were found compared to the rest of the calves.Subclinical BNP was found to occur at a high incidence in a herd of cattle with fatal cases of BNP.

View Article: PubMed Central - PubMed

Affiliation: The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh EH25 9RG, Scotland, UK. lottie.bell@ed.ac.uk.

ABSTRACT

Background: Bovine Neonatal Pancytopenia (BNP) is a disease of calves characterised by bone marrow trilineage hypoplasia, mediated by ingestion of alloantibodies in colostrum. Suspected subclinical forms of BNP have been reported, suggesting that observed clinical cases may not represent the full extent of the disease. However to date there are no objective data available on the incidence of subclinical disease or its temporal distribution. This study aimed to 1) ascertain whether subclinical BNP occurs and, if so, to determine the incidence on an affected farm and 2) determine whether there is evidence of temporal clustering of BNP cases on this farm. To achieve these aims, haematological screening of calves born on the farm during one calving season was carried out, utilising blood samples collected at defined ages. These data were then analysed in comparison to data from both known BNP-free control animals and histopathologically confirmed BNP cases. An ordinal logistic regression model was used to create a composite haematology score to predict the probabilities of calves being normal, based on their haematology measurements at 10-14 days old.

Results: This study revealed that 15% (21 of 139) of the clinically normal calves on this farm had profoundly abnormal haematology (<5% chance of being normal) and could be defined as affected by subclinical BNP. Together with clinical BNP cases, this gave the study farm a BNP incidence of 18%. Calves with BNP were found to be distributed throughout the calving period, with no clustering, and no significant differences in the date of birth of cases or subclinical cases were found compared to the rest of the calves. This study did not find any evidence of increased mortality or increased time from birth to sale in subclinical BNP calves but, as the study only involved a single farm and adverse effects may be determined by other inter-current diseases it remains possible that subclinical BNP has a detrimental impact on the health and productivity of calves under certain circumstances.

Conclusions: Subclinical BNP was found to occur at a high incidence in a herd of cattle with fatal cases of BNP.

Show MeSH
Related in: MedlinePlus