Shearing induces secondary biomarkers responses of thermal stress in sheep

The study involved 30 non-pregnant, clinically healthy Comisana sheep in order to evaluate the effect of shearing on rectal temperature (RT), respiratory rate (RR), heart rate (HR), white blood cells (WBC), red blood cells (RBC), haematocrit (Hct), haemoglobin (Hb) and total proteins (TP). During the spring season the animals were divided into two groups: twenty sheep, designated as the experimental group, were shorn (Group A), and ten sheep, designed as the control group, were left unshorn (Group B). All animals were weighed using a mechanical balance in the morning before shearing and after shearing. During the experimental period ambient temperature and relative humidity were recorded, while the temperature-humidity index was calculated. The measurements of studied secondary stress parameters were assessed before shearing (day 0), 1, 15, 30, 45 and 60 days after shearing in the experimental group and at the same time points in the control group. Two-way repeated measure analysis of variance (ANOVA), followed by Bonferroni’s multiple post hoc comparison test, showed a significant effect of shearing and time on RT, RR, HR, RBC, Hct and Hb. These parameters play an important role in providing complementary information for the assessment of thermal stress, since they are affected in response to the stress of shearing, suggesting that they are useful secondary stress indices in shorn sheep. These modifications are useful to monitor the stressful conditions, but also to evaluate health and welfare of animals, and to improve their productivity.