Complete blood count data and leukocyte expression of cytokine genes and cytokine receptor genes associated with bovine respiratory disease in calves

Authors: Lindholm-Perry, Amanda; Kuehn, Larry; McDaneld, Tara; Miles, Jeremy; Workman, Aspen; Chitko-Mckown, Carol; Keele, John

Submitted to: BMC Research Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2018
Publication Date: 11/3/2018
Citation: Lindholm-Perry, A.K., Kuehn, L.A., McDaneld, T.G., Miles, J.R., Workman, A.M., Chitko-McKown, C.G., Keele, J.W. 2018. Complete blood count data and leukocyte expression of cytokine genes and cytokine receptor genes associated with bovine respiratory disease in calves. BMC Research Notes. 11:786. https://doi.org/10.1186/s13104-018-3900-x.
DOI: https://doi.org/10.1186/s13104-018-3900-x

Interpretive Summary: The ability to predict whether an animal could be succumbing to bovine respiratory disease (BRD) would benefit producers by allowing them to manage animals with higher susceptibility differently. Producers could reduce their exposure to illness, monitoring susceptible animals more closely for illness or treating animals prophylactically are examples that could help to mitigate risk of BRD. Previous studies have identified relationships between white blood cells, response to vaccine and health records in calves. The purpose of this study was to evaluate the complete blood count and the expression of genes with important immune function (cytokines) for differences between healthy and sick animals at various time points (before weaning, at weaning and upon diagnosis of BRD). We identified differences in the levels of subsets of white blood cells. Neutrophils were higher and monocytes were lower in sick animals at the time of BRD diagnosis. In addition, monocytes were lower in sick animals at weaning. Three of the genes evaluated were detected in higher abundance in the animals with BRD at the time of diagnosis. The changes in gene expression were suggestive of a response to pathogens. We have identified CBC values that were different in this set of animals between those that became sick and those that remained healthy at various time points. In addition, we identified differences among several cytokine genes and their receptors that may also be useful biomarkers of BRD. White blood cell counts and cytokine expression data may provide insight into an animal’s health and is an avenue for future study.

Technical Abstract: Objective: The purpose of this study was to evaluate potential relationships between cytokine gene expression, complete blood counts (CBC) and animals that were sick or would become sick. The CBC and the transcript abundance of cytokines and their receptors expressed in leukocytes were measured from calves at two early timepoints, and again after diagnosis with bovine respiratory disease (BRD). Results: Blood was collected from calves at pre-conditioning (n = 796) and weaning (n = 791) for CBC. Blood counts were also measured for the calves with BRD (n = 13), and asymptomatic calves (n = 75) after weaning. The CBC were compared for these animals at 3 time points. At diagnosis, neutrophils were higher and basophils lower in sick animals (P < 0.05). To further characterize BRD responses, transcript abundance of 84 cytokine genes were evaluated in 5 calves with BRD and 9 asymptomatic animals at all time points. There was more data for CBC than transcript abundance; hence, animal and temporary environmental correlations between CBC and transcript abundance were exploited to improve the power of the transcript abundance data. Expression of CCL16, CXCR1, CCR1 was increased in BRD positive animals compared to controls (P-corrected < 0.1). Cytokine expression data may help to provide insight into an animal’s health.