Habituation to Livestock Trailer and Its Influence on Stress Responses during Transportation in Goats

SIMPLE SUMMARY: Long-duration transportation of goats can cause significant changes in their behavior and physiology that could compromise their welfare. This study was conducted to determine if repeated exposure to livestock trailers can be beneficial in reducing stress responses due to prolonged transportation in goats. A total of 168 uncastrated male Spanish goats were divided into groups and maintained on two identical paddocks. One group was fed a concentrate supplement inside two livestock trailers for 4 weeks, and the other group was fed the same diet in the feeding area with no trailers. After the habituation period, the goats were transported for 10 h in four replicates, and blood samples were collected every two hours to evaluate stress responses. Phenylethylamine and 5-methoxytryptamine concentrations were significantly higher in the group habituated to trailers compared to the group not habituated to trailers. Dopamine, 5-methoxytryptamine, and metanephrine concentrations were significantly influenced by transportation time. The blood biogenic amine concentrations indicate that the habituation of goats to livestock trailers may be beneficial during transportation for long periods. ABSTRACT: This experiment was conducted to determine the effects of habituation to livestock trailers on stress responses in goats transported for long periods. Intact male Spanish goats (12-month old; BW = 31.6 ± 0.34 kg; N = 168) were separated into two treatment (TRT) groups and maintained on two different paddocks. Concentrate supplement was fed to one group inside two livestock trailers (5.0 × 2.3 m each; habituated group, H), while the other group received the concentrate supplement, but not inside the trailers (non-habituated, NH). After 4 weeks of habituation period, goats were subjected to a 10-h transportation stress in four replicates (n = 21 goats/replicate/TRT). Blood samples were collected by a trained individual by jugular venipuncture into vacutainer tubes before loading (Preload), 20 min after loading (0 h), and at 2-h intervals thereafter (Time) for analysis of stress responses. There was a tendency for a TRT effect (p < 0.1) on tyramine and metanephrine concentrations. Phenylethylamine and 5-methoxytryptamine concentrations were significantly greater (p < 0.05) in the H group compared to the NH group. Both dopamine and 5-methoxytryptamine concentrations decreased (p < 0.05) with transportation time; however, TRT × Time interaction effects were not significant. Habituation to trailers may be beneficial in mood and energy stabilization in goats during long-distance transportation.