Fig. 6

Analysis of the metabolic serum indicators in calves. A–L Boxplots of the considered hematological indicators with significant differences among different time points. M Principal component analysis plot of all these assessed indicators in each sample group. Heatmaps of Spearman’s rank correlations between respiratory health indicators and growth performance with the considered hematological indicators at time points A (N), B (O), and C (P). In A–L, the yellow dot denotes average values, and a one-way analysis of variance was used to assess difference levels among groups (ns, non-significant; *, p < 0.05; **, p < 0.01; ***, p < 0.001). In N–P, correlations were calculated using clinical data from the 10 marked calves; pane colors denote the strength and direction of relevance (green for positive, blue for negative), and asterisks indicate significance levels of relevance (*, p < 0.05; **, p < 0.01; ***, p < 0.001)