Lynch, E.M. and Earley, B. and McGee, M. and Doyle, S.
Effect of abrupt weaning at housing on leukocyte
distribution, functional activity of neutrophils, and
acute phase protein response of beef calves.
BMC Veterinary Research, 6 (39).
Background: Sixteen, spring-born, single suckled, castrated male calves of Limousin × Holstein-Friesian and
Simmental × Holstein-Friesian dams respectively, were used to investigate the effect of weaning on total leukocyte
and differential counts, neutrophil functional activity, lymphocyte immunophenotypes, and acute phase protein
response. Calves grazed with their dams until the end of the grazing season when they were housed in a slatted
floor shed. On the day of housing, calves were assigned to a treatment, (i) abruptly weaned (W: n = 8) or (ii) nonweaned
(controls) (C: n = 8). Weaned calves were housed in pens without their dams, whereas non-weaned
(control) calves were housed with their dams. Blood was collected on day -7, 0 (housing), 2, 7, and 14 to
determine total leukocyte and differential counts and concentration of fibrinogen and haptoglobin. Lymphocyte
immunophenotypes were characterised using selected surface antigens (CD4+, CD8+, WC1+ (gδ T cells), MHC Class
II+ lymphocytes), and the functional activities of neutrophils (surface expression of L-selectin (CD62L), phagocytic
and oxidative burst activity) were investigated using flow cytometry.
Results: Treatment × sampling time interactions (P < 0.05) were detected for total leukocyte and neutrophil
counts, all lymphocyte subsets, mean fluorescence intensity of CD62L+ neutrophils, and percentage neutrophils
performing phagocytosis. On d 2, total leukocyte and neutrophil count increased (P < 0.001), and percentage CD4+
and CD8+ lymphocytes, percentage phagocytic neutrophils, mean fluorescence intensity of CD62L+ neutrophils
decreased (P < 0.05) in W compared with baseline (d 0), whereas they were unchanged (P > 0.05) in C. On d 2,
percentage WC1+ lymphocytes decreased (P < 0.05), whereas percentage MHC class II+ lymphocytes increased (P <
0.05) in W and C, however the magnitude of change was greater in W than C. There were no treatment ×
sampling time interactions (P > 0.05) for monocyte, eosinophil, and basophil counts, percentage G1+ neutrophils,
or percentage oxidative burst positive neutrophils.
Conclusions: Abrupt weaning resulted in increased neutrophil counts and impaired trafficking and phagocytic
function. Together with the changes in lymphocyte subsets, the results suggest that there was a greater transitory
reduction in immune function at housing in abruptly weaned than non-weaned beef calves.
||This study was supported by a Teagasc Walsh Fellowship to E. M. Lynch. The
authors thank E. Mulligan and P. Lawrence (Teagasc, Grange Beef Research
Centre) for their excellent technical assistance with blood sample collection,
and M. Murray (Teagasc Animal, Grassland and Bioscience Research Centre)
and J. Larkin (Teagasc, Grange Beef Research Centre) for their excellent
technical assistance with haematological and flow cytometric analysis,
respectively. Many thanks are due to the farm staff at Teagasc, Grange Beef
Research Centre for the care and management of the animals. E. M. Lynch
was a recipient of a Teagasc Walsh Fellowship and a John and Pat Hume
Scholarship, National University of Ireland, Maynooth, Ireland.
||abrupt weaning; housing; leukocyte
distribution; neutrophil functional activity; acute phase protein response; beef calves;
||Science & Engineering > Biology
Dr. Sean Doyle
||09 Feb 2011 15:37
|Journal or Publication Title:
||BMC Veterinary Research
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