• Blood immune transcriptome analysis of artificially fed dairy calves and naturally suckled beef calves from birth to 7 days of age

      Surlis, Carla; Earley, Bernadette; McGee, Mark; Keogh, Kate; Cormican, Paul; Blackshields, Gordon; Tiernan, Katie; Dunn, Amanda; Morrison, Steven; Arguello, A.; et al. (Nature Publishing Group, 2018-10-18)
      Neonatal calves possess a very immature and naïve immune system and are reliant on the intake of maternal colostrum for passive transfer of immunoglobulins. Variation in colostrum management of beef and dairy calves is thought to affect early immune development. Therefore, the objective of this study was to examine changes in gene expression and investigate molecular pathways involved in the immune-competence development of neonatal Holstein dairy calves and naturally suckled beef calves using next generation RNA-sequencing during the first week of life. Jugular whole blood samples were collected from Holstein (H) dairy calves (n = 8) artificially fed 5% B.W. colostrum, and from beef calves which were the progenies of Charolais-Limousin (CL; n = 7) and Limousin-Friesian beef suckler cows (LF; n = 7), for subsequent RNA isolation. In dairy calves, there was a surge in pro-inflammatory cytokine gene expression possibly due to the stress of separation from the dam. LF calves exhibited early signs of humoral immune development with observed increases in the expression genes coding for Ig receptors, which was not evident in the other breeds by 7 days of age. Immune and health related DEGs identified as upregulated in beef calves are prospective contender genes for the classification of biomarkers for immune-competence development, and will contribute towards a greater understanding of the development of an immune response in neonatal calves.
    • Genome wide association study of passive immunity and disease traits in beef-suckler and dairy calves on Irish farms

      Johnston, Dayle; Mukiibi, Robert; Waters, Sinéad M.; McGee, Mark; Surlis, Carla; McClure, Jennifer C.; McClure, Matthew C.; Todd, Cynthia G.; Earley, Bernadette; Department of Agriculture, Food and the Marine; et al. (Springer Science and Business Media LLC, 2020-11-04)
      Calves with lower concentrations of immunoglobulin G (IgG) in their blood, have a greater risk of developing diseases. There is a lack of knowledge on genetic markers known to be associated with immunological variability or disease resistance. Therefore, the objective of this study was to identify SNP markers associated with passive immunity measures (serum IgG, serum protein, albumin, globulin and total protein concentrations, total solids Brix percentage, zinc sulphate turbidity units) and disease (pneumonia, diarrhoea, crude illness) traits in Irish commercial beef-suckler and dairy calves through genome wide association studies (GWAS). Genotyping was performed on DNA samples from beef-suckler (n = 698) and dairy (n = 1178) calves, using the IDBv3 chip. Heritability of passive immunity associated traits (range 0.02–0.22) and the disease traits (range 0.03–0.20) were low-to-moderate. Twenty-five and fifteen SNPs approached genome wide significance (P < 5 × 10−5) for the passive immunity and the disease traits, respectively. One SNP “ARS-BFGL-BAC-27914” reached Bonferroni genome wide significance (P < 1.15 × 10−6) for an association with serum IgG concentration in beef calves. Further work will evaluate these SNPs in larger cattle populations and assess their contribution to genomic selection breeding strategies, aimed towards producing more disease resistant livestock.