Abstract
This study aimed to investigate effects of transport age of calves (14 vs. 28 d), and of calf and dam characteristics, on immunoglobulin titers and hematological variables of veal calves. Calves (n = 683) were transported to a veal farm at 14 or 28 d of age. Natural antibodies N-IgG, N-IgM, and N-IgA against phosphorylcholine conjugated to bovine serum albumin (PC-BSA) were measured in serum of the dams 1 wk before calving and in first colostrum. These antibodies were also measured in serum of calves 1 wk after birth, 1 d before transport, and in wk 2 and 10 posttransport at the veal farm. Hematological variables were assessed in calves 1 d before transport and in wk 2 posttransport. One day before transport, titers of N-IgG, N-IgM, N-IgA, and neutrophil counts were higher, and lymphocyte counts were lower in 14-d-old calves compared with 28-d-old calves. In wk 2 at the veal farm, calves transported at 14 d of age had higher N-IgG titers and neutrophil counts, but lower N-IgM and N-IgA titers, and lymphocyte counts than calves transported at 28 d. In wk 1 and 1 d before transport, N-Ig in calves were positively related to N-Ig in colostrum. In wk 2 and 10 at the veal farm, N-IgG in calves was positively related to N-IgG in colostrum. The N-IgG titers in calves at the dairy farm were negatively related to the likelihood of being individually treated with antibiotics or other medicines at the veal farm. Our results suggest that calves transported to the veal farm at 28 d of age showed a more advanced development of their adaptive immunity than calves transported at 14 d of age. Quality of colostrum might have long-term consequences for N-IgG titers and immunity in veal calves.
Highlights
In the Netherlands, male calves born on dairy farms are transported at a minimum age of 14 d, first to a collection center and to a veal farm (Marcato et al, 2018)
Calves that were transported at 28 d had a lower mean corpuscular volume (MCV) (Δ = −1.67 fL), mean corpuscular hemoglobin (MCH) (Δ = −35.6 amol), red cell distribution width (Δ = −1.12%), white blood cell count (WBC) (Δ = −0.7 × 109/L), neutrophils [cell count (Δ = −1.1 × 109/L) and proportion (Δ = −7.97%)], and monocytes [cell count (Δ = −2.12 × 109/L) and proportion (Δ = −2.14%)] compared with calves transported at 14 d
In wk 2 posttransport, calves transported at 28 d had a lower MCV (Δ = −1.81 fL), MCH (Δ = −24 amol), WBC (Δ = −1.21 × 109/L), neutrophils [cell count (Δ = −1.61 × 109/L) and proportion (Δ = −12.05%)], and basophil count (Δ = −0.02 × 109/L) compared with calves transported at 14 d
Summary
In the Netherlands, male (and surplus female) calves born on dairy farms are transported at a minimum age of 14 d, first to a collection center and to a veal farm (Marcato et al, 2018). BW and the clinical health condition of calves upon arrival at the veal farm (Renaud et al, 2018b; Scott et al, 2019) as well as biomarkers analyzed in a blood sample taken at arrival, including immunoglobulins (Pardon et al, 2015; Goetz et al, 2021), cholesterol (Renaud et al, 2018b), or specific immune cell counts (von Konigslow et al, 2020), were all significantly correlated with later risks of disease and mortality These studies suggest that both transport and husbandry characteristics at the dairy farm of origin may be important determinants of the biological state of a calf when it arrives at the veal farm. Identifying which specific environmental or animal-based factors may play a causal role in influencing robustness of veal calves has not yet been well investigated
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