Abstract: This study was aimed to explore the effect of anti-stress treatment on disease occurrence of the heifers after arrival at feedlots. Before transport, the first batch of 69 heifers were injected intra-muscularily(im) Catosal, while the second bactch of 39 heifers were injected intra-muscularily(im) inactivated Mycoplasma bovis vaccine. The duration of transportation was 32 h and 36 h respectively without providing any water or feed for the heifers during the highway. Observation continued for 30 d after transportation and record the temperature and humidity of the environment as well as morbidity information. The results show that all heifers almost at status of heat stress all the time. The first batch of beef cattle and the second in succession after the arrival of disease, the accumulated morbidities of the two tested groups are lower than that of the two control groups before the ninth day and the thirteenth day respectively after transport in two batches, but later, the accumulated morbidities of the two tested groups are higher than that of the two control groups in two batches; the morbidity and the mortality of the first batch are higher for 1. 23% and 20.29% than that of the second batch.

Key words: Catosal; anti-stress; transport stress syndrome of beef cattle