Abstract:
The aim of this study was to investigate effects of pre-transport diets, transport durations
and transport conditions on immune cell subsets, haptoglobin, cortisol and bilirubin of young
calves upon arrival at the veal farm. An experiment was conducted with a 2 × 2 × 2 factorial
arrangement with 3 factors: 1) provision of rearing milk or electrolytes at the collection center
(CC); 2) transport duration (6 or 18 hours) and 3) transport condition (open truck or conditioned
truck). Holstein-Friesian and cross-bred calves were used (N = 368; 18 ± 4 days;
45.3 ± 3.3 kg). Blood samples were collected from calves (N = 128) at the collection center,
immediately post-transport (T0) and 4, 24, 48 hours, week 1, 3 and 5 post-transport. Blood
was analyzed for cortisol, bilirubin, haptoglobin, IgG and IgM. Moreover, cell counts of neutrophils,
lymphocytes, monocytes, basophils and eosinophils were measured in blood samples
taken at the collection center and T0. In these same blood samples, different
lymphocyte populations were characterized by flow cytometry, including CD14+ cells, NK
cells, δγ+ T cells, CD8+ cells, CD4+ cells and CD21+ cells. Calves transported in the conditioned
truck had higher amounts of white blood cell count (WBC) (Δ = 1.39 × 109/l; P = 0.01),
monocytes (Δ = 0.21 × 109/l; P = 0.04), neutrophils (Δ = 0.93 × 109/l; P = 0.003), than calves
transported in the open truck regardless, of pre-transport diet or transport duration. The
study showed that transport condition and duration influenced parts of the innate immune
system of young veal calves. Cortisol, bilirubin and WBC seemed to be connected by similar
underlying mechanisms in relation to transport conditions. However, it is unclear which specific
pathways in the immune system of young calves are affected by different transport conditions
(e.g. temperature, humidity, draught).
Description:
S1 Fig. Design of the truck and the trailer for batch 1 (A) and batch 2 (B) of calves.
M6C = milk, 6 hours transport, conditioned truck; M18C = milk, 18 hours transport, conditioned
truck; M6O = milk, 6 hours transport, open truck; M18O = milk, 18 hours transport,
open truck; E6C = electrolytes, 6 hours transport, conditioned truck; E18C = electrolytes, 18
hours transport, conditioned truck; E6O = electrolytes, 6 hours transport, open truck;
E18O = electrolytes, 18 hours transport, open truck.
S1 Table. Effects of diet composition (electrolytes vs milk) at the collection center (CC),
transport condition (conditioned vs open truck) and transport duration (6 vs 18 hours) on
the difference between CC and post-transport (T0) measurements (deltas, Δ = T0 –CC) of
different cell subsets in blood of young veal calves (LS means). 1% = proportion relative to
lymphocytes; 2SEM = standard error of the means; 3Perf+ = CD8+ T cells, NK cells, CD4+ and
δγ+ T cells were stimulated with perforin to examine the functionality of these cells and how
their functionality was affected by the different treatments.
