Effects of Transport Duration and Pre-Transport Fasting on Blood Biochemistry in Dorper × Mongolian Sheep.

Simple Summary: Transport is an unavoidable and important part of livestock husbandry. Live sheep transport is a period of high risk to their welfare, and potentially a huge hidden economic loss due to the effects on their health and/or the quality of their carcasses. Public concern about livestock transport indicates that it is important to improve the welfare of animals being transported. Prolonged transport and pre-transport fasting may particularly stress sheep, as well as potentially adversely affecting subsequent growth and/or carcass quality after slaughter. We investigated the effects of different transport times and pre-transport feeding during summer on the welfare of transported sheep of the Dorper × Mongolian breed, which are typical of the region and may be tolerant of the high temperatures in the Inner Mongolian summer. We selected 4-month-old male sheep to conduct two transport experiments, measuring the relevant blood biochemical indicators to evaluate the level of animal welfare. We found that three hours transport, compared with one hour, reduced the nutritional status of sheep, and that 12 h fasting before transport reduced the sheep's nutritional status. Increased cortisol in sheep fed pre-transport may indicate that sheep are less stressed by the transport if they have been fasted. We therefore recommend that, during hot weather, sheep transport is confined to short periods. Regarding fasting, we recommend that sheep are not fasted for a long period beforehand, because of the decline in nutritional status. Transport is a high-risk time for sheep, especially if the distances are long and sheep are fasted for a long time beforehand. Two experiments were conducted to compare transport durations of 1 hour (1 h) and 3 hours (3 h) and the effects of feeding before transport using Dorper × Mongolian sheep, which are typical of the region and may be tolerant of the high temperatures in the Inner Mongolian summer. Thirty 4-month-old male sheep were randomly divided into two treatment groups, with 15 sheep/treatment in each experiment, to evaluate the effects on blood biochemical indicators, stress hormone levels, rectal temperatures, and antioxidant status of lambs in summer. In Experiment 1, the levels of triglycerides and free fatty acids after 3 h transport were significantly lower than after 1 h transport (p < 0.05). The levels of thyroxine and malondialdehyde in blood were greater after 3 h transport than 1 h transport (p < 0.05). Creatine kinase levels after 3 h transport tended to be lower than after 1 h transport (p = 0.051). In Experiment 2, the levels of urea and superoxide dismutase in the group fasted pre-transport was significantly lower than those of the group fed pre-transport (p < 0.05). The serum cortisol level in the pre-transport fed group was higher compared to the group fed pre-transport (p = 0.04). Total antioxidant capacity in the pre-transport fasted group tended to be lower compared to that in the pre-transport fed group (p < 0.0001). We conclude that the reduction in nutritional status of sheep transported for longer and without feed pre-transport suggests that transporting sheep in hot conditions in northern China after fasting for a long period should be restricted. However, a decrease in the stress induced by transport following fasting is worthy of further study. [ABSTRACT FROM AUTHOR]