Physiological Stress Assays With Non-Invasive Method In Captive And Released Przewalski Horse

This work aims to study the physiological stress of the captive and released adult male Przewalski horse Equus przewalskii, using the non-invasive method to determine the fecal glucocorticoid metabolites(FGM), in Xinjiang Przewalski Horse Breeding and Studying Centre (89°14′–89°36′N,45°49′–46°04′E) and Kalamaili Natural Reserve of north Xinjiang(44°36′–46°00′E,88°30′–90°03′N) from 2006 to 2007. We studied the seasonal pattern of physiological stress of released Przewalski horses, the FGM change of captive Przewalski horse from winter to summer, the difference of stress level between captive and released wild horses in winter, the stress response of Przewalski's horse Equus prezwalskii under transportation stimulus. Meanwhile, the possible stressors of each group of adult male Przewalski horse are analyzed, including the different research object in the same season, the same research object in the different season, the individual in different conditions. The results are listed below.(1)The results showed that the FGM concentration of the resealed stallion and bachelor group had the obvious seasonal variation, which there was significant difference in seasons. The physiological stress level of bachelors in season was in an order of summer > autumn > spring > winter; and the order of stallions was autumn >summer > spring > winter.(2)Result from the FGM concentration of captive horses showed that there was significant differences of stress level between summer and winter, and we concluded that the high temperature and competing for female were the main stressor leading to the higher stress level in summer.(3)Result from the FGM concentration of captive and released horses in winter showed that there are significant differences in mean values of fecal glucocorticoid metabolites among all groups(P<0.05), including released bachelors, released stallions, captive stallions and captive bachelors The physiological stress level in all groups reveals in an order of captive bachelors > captive stallions > released stallions > released bachelors, which indicated the captive horses suffer from more stressors.(4)Both male and female Przewalski's horses were sensitive to transportation stimulus. The FGM kept normal physiological average value before transportation, however the wild horses were suffered strong effects durning transportation, which the FGM began to increase about 1.75h and reached the maximum values about 24h post-transportation, 2.3 times as pre-transportation. Later, the FGM began to decrease continuously, and was close to normal value. about 72h.