Objective: To what extent do factors such as long periods of transportation by vehicles especially in inclement weather, crowdness in trailers and the resultant stress can cause changes in haematological parameters and how these changes can be differentiated from haematological changes induced by other causes.
Design: Independent concurrent experimental studies. Animal: Twenty clinically healty male calves, 4-10 months old and average weight of 160kg.
Procedure: During a period of 42 days experiment, the calves were kept indoors and fed alfalfa hay and corn silage ad libitum. After a period of adaptation, on day 21, the first blood sample was taken from all calves in order to have the baseline data. Then the calves were divided into three groups: Control 1 (5 calves) which kept at stable and had free access to food and water during a 12-hour period of transportation of the experimental group. Control 2 (5 calves) which confined at stable but were deprived of food and water at the same time, and experiment (10 calves) which were transported and deprived of food and water. On day 26, when transportation began, blood samples were obtained simultaneously from all groups at 0,1,3,6 and 12 hours of transportation. On day 27, blood samples were taken from the experimental group and both control groups. Then on days 31 and 42, blood samples were taken from the both experimental and control groups (2). Haematological parameters were measured with routine laboratory methods.
Statistical analysis: A analysis of Variance (ANOVA) and paired student “t”.
Results: Haematological examination of blood samples revealed that the number of RBCs, WBCs, neutrophils and the level of corlisol and PCV significantly increased, but lymphocytes and monocytes significantly decreased in the experimental group compared with the control groups (I &2) on the day of transportation (P<0.05). Conclusion: Transport stress caused significant changes in serum cortisol values and haematological parameters in calves. Furthermore; the maximum effects of transportation-induced haematological changes are produced in the early stage of transport. More significant changes are produced in the early stage of transport. More significant changes in haematological parameters and serum cortisol values are expected during longer transport periods. These changes are induced by physiological changes in the haematological system and adrenal gland during stress. J. Fac. Vet. Med. Univ. Tehran. 57, 2: 71-76, 2002.
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