Assessing Physiological and Behavioral Stress Parameters in Trained Goats During Repeated Blood Sampling

Blood sampling by venipuncture is a routine procedure used in animal experiments and veterinary diagnostics. It can cause stress due to restraint and pain associated with penetration of the skin by a needle. When stressful procedures are repeated, stress can increase through anticipation after negative experiences or decrease due to habituation and/or positive reinforcement. The aim of this study was to describe the reaction to repeated blood sampling on the affective state of the animals. We wanted to observe how repeated blood sampling would affect stress parameters in goats that underwent an intensive cooperative vet care training protocol and were managed with a focus on gentle handling. Eight dairy goats underwent weekly blood sampling over a four-month period as part of a transfer study. Stress parameters were assessed using serum cortisol concentration, temperature changes in the inner corner of the eye measured by infrared thermography, and an ethogram showing voluntary and aversive behavior. Neither the serum cortisol concentration nor the eye temperature changed significantly over time during blood sampling. However, the ethogram showed that the goats approached the blood sampling position significantly faster and more voluntarily. In this study, we did not observe changes within the measured physiological stress parameters due to repeated blood sampling over three months. However, the voluntary behavior of the trained goats increased over time as a result of positive reinforcement training and habituation.