Dynamics of Biochemical Parameters, Inflammatory and Stress Markers in Lambs Undergoing Caudectomy Using Two Different Methods

Abstract

Zootechnical practices such as tail docking are still in use in dairy sheep farming, performed in the first week of life, mainly by rubber ring and only rarely by surgical methods. In this study, we evaluated the impact of caudectomy on ovine stress levels, inflammation, and health status by comparing tail docking carried out using rubber rings or surgical amputation. Twenty-one lambs were randomly selected and equally allocated into three groups: controls (n = 7), lambs with tail cut by rubber rings (n = 7), and lambs with caudectomy performed by surgical practice (n = 7). Several biochemical parameters and inflammatory markers were monitored at different times post-caudectomy, as well as wool levels of the stress marker cortisol. Our data revealed that lambs that underwent tail docking by rubber rings, but not by surgical procedure, presented inflammation and stress, as well as a moderate increase in muscular damage markers. These results are useful for the evaluation of animal welfare in dairy sheep that underwent caudectomy, highlighting the need to re-evaluate this procedure, as well as the ways in which it is performed.

Keywords: biochemical profile; caudectomy; cortisol; inflammatory status; sheep.

Figure 1

Schematic outline of the experimental study highlighting the key time points. Twenty-one lambs were enrolled in the study and randomly divided into three groups: group A (control group, n = 7), group B (tail docking by rubber ring, n = 7), and group C (tail docking by surgical amputation, n = 7). Serum samples were collected before treatment (T₀) and five times after caudectomy: T₁ (36–40 h), T₂ (3 days), T₃ (7 days), T₄ (14 days), and T₅ (21 days) for biochemical analysis and evaluation of inflammatory markers. At T₀ and T₄ (14 days), wool was also collected for cortisol evaluation. Image created with Biorender.com (accessed on 7 July 2025).

Figure 2

Kinetics of markers of hepatic function in serum samples taken throughout the experiment. Twenty-one lambs were enrolled in the study and randomly divided into three groups: group A (control group, n = 7), group B (tail docking by rubber ring, n = 7), and group C (tail docking by surgical amputation, n = 7). Serum samples were obtained through the experiment, and changes in the levels of GOT/AST, GPT/ALT, bilirubin, and cholesterol were monitored using an automated spectrophotometer. For each parameter, data post-treatment (T₁, T₂, T₃, T₄, and T₅) were compared to the data pre-treatment (T₀) using the parametric ANOVA followed by Dunnett’s multiple comparison tests or the non-parametric Kruskal–Wallis test followed by Dunn’s multiple comparison test.

Figure 3

Kinetics of markers of renal function, CPK and glucose in serum samples taken throughout the experiment. Twenty-one lambs were enrolled in the study and randomly divided into three groups: group A (control group, n = 7), group B (tail docking by rubber ring, n = 7), group C (tail docking by surgical amputation, n = 7). Serum samples were obtained through the experiment, and changes in the levels of creatinine, urea, CPK, glucose were monitored using an automated spectrophotometer. For each parameter, data post-treatment (T₁, T₂, T₃, T₄, T₅) were compared to the pre-treatment (T₀) data using the parametric ANOVA followed by Dunnett’s multiple comparison tests or the non-parametric Kruskal–Wallis test followed by Dunn’s multiple comparison test; * p < 0.05, ** p < 0.01, *** p < 0.001.

Figure 4

Kinetics of protein levels in serum samples taken throughout the experiment. Twenty-one lambs were enrolled in the study and randomly divided into three groups: group A (control group, n = 7), group B (tail docking by rubber ring, n = 7), and group C (tail docking by surgical amputation, n = 7). Serum samples were obtained through the experiment, and changes in the levels of total proteins were monitored using an automated spectrophotometer. Proportions of serum proteins (albumin, α1-globulin, α2-globulin, β-globulin, γ-globulin) were determined through electrophoretic analysis. For each parameter, data post-treatment (T₁, T₂, T₃, T₄, T₅) were compared to the pre-treatment (T₀) data using the parametric ANOVA followed by Dunnett’s multiple comparison tests or the non-parametric Kruskal–Wallis test followed by Dunn’s multiple comparison test; ** p < 0.01, *** p < 0.001.

Figure 5

Kinetics of inflammatory markers in serum samples taken throughout the experiment. Twenty-one lambs were enrolled in the study and randomly divided into three groups: group A (control group, n = 7), group B (tail docking by rubber ring, n = 7), and group C (tail docking by surgical amputation, n = 7). Serum samples were obtained through the experiment, and changes in the levels of fibrinogen and transferrin were monitored using an automated blood coagulation analyser and a spectrophotometer, respectively. For each parameter, data post-treatment (T₁, T₂, T₃, T₄, T₅) were compared to the pre-treatment (T₀) data using the non-parametric Kruskal–Wallis test followed by Dunn’s multiple comparison test; ** p < 0.01.

Figure 6

Impact of caudectomy on wool cortisol levels. Twenty lambs were enrolled in the study and randomly divided into three groups: group A (control group, n = 7), group B (tail docking by rubber ring, n = 7), and group C (tail docking by surgical amputation, n = 7). Wool samples were taken before treatment (T₀) and at day 14 (T₄), and their cortisol levels were determined. For each group, differences between the two time points were compared using an unpaired t-test; *** p < 0.001.