**4. Conclusions**

From this preliminary study it can be concluded that even in a controlled replication of the marketing process, where calves were weaned a month before the study, were handled calmly, transported at a low stocking density, and fasted without being mixed or exposed to an unfamiliar environment, there was a significant effect of transport and fasting on the calves, which were measurable through MET, TT, blood indicators such as CK, glucose, β-HB and their live weight. This study was limited to a small number of animals, lacked a control group, and was under simulated commercial conditions. Nevertheless, the findings strongly sugges<sup>t</sup> that more extensive studies of calves undergoing true, commercial marketing are urgently required. Exposure to a real marketing situation, with additional real-life stressors such as handling by untrained staff, weaning just before loading or when they arrive in the market, transport both to and from the market, fasting in pens without protection against adverse weather conditions, stocking at higher densities, and getting mixed with unfamiliar animals would undoubtedly produce greater stress, with repercussions for calf welfare and productivity.

**Author Contributions:** Conceptualization, investigation, methodology and execution, V.B. and C.G.; Data analysis, V.B. and G.A.-J.; Writing—original draft, V.B. and C.G.; Writing—review and editing, V.B., C.G. and G.A.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors would like to thank Jaime Vargas for his help in the experiment execution, Dr. Rodrigo Arias for his advisory and Professor Toby Knowles for the final language editing.

**Conflicts of Interest:** The authors declare no conflicts of interest.
