The influence of transport stress on the humoral immunological response of calves induced by Mannheimia haemolytica leukotoxin.
In the contemporary systems of cattle production, transport stress is the most essential poly-etiological factor responsible for inducing unfavourable reactions in the animals. The main reason for this phenomenon is the immunosuppressive effect of steroid hormones on cellular and humoral protective mechanisms. The purpose of the present study was to establish the relationship between the cortisol concentration as an indicator of the stress reaction occuring directly after the transportation of calves and the specific humoral immune response to the leukotoxin (Lkt) antigen produced by the M. haemolytica strain. The experiment was carried out on 19 clinically healthy calves, weighing about 100 kg and transported by track for about 2 hours. After the delivery of the animals for feeding to the traditional cattle-house, the calves were immunized s.c.: group I with 1 ml Lkt (in conc.--10 microg/ml) with 1 ml of adjuvant on the 1st and 14th day after the transportation, group II with the same Lkt doses on the 3rd and 16th day after the transportation. The animals of the control group were vaccinated on the 1st and 14th day after the transportation with the twice diluted adjuvant. In examined sera the cortisol concentrations and the level of Lkt antibodies were measured by ELISA test. The cytotoxin neutralizing (CN) antibody level (cytotoxity assay) was determined with a simple visual assay. The study revealed, significant differences (P < or = 0.01) in serum cortisol levels between the control and experimental animals. The analysis of the absorbance of the sera in both groups immunized with Lkt showed substantial differences (P < or = 0.05) from the 6th through to 22nd day of the experiment compared with the control group. The analysis of the results of CN antibody titers showed no differences between the sera from group I and II. Based on the results obtained in this experiment it can be assumed, that a short transportation stress has no important influence on the level of specific humoral anti-Lkt response.
Wernicki
A
A
Department of General Prophylaxis and Avian Diseases, Faculty of Veterinary Medicine, University of Agriculture, Akademicka 12, 20-033 Lublin, Poland. wernic@agros.ar.lublin.pl
Urban-Chmiel
R
R
Mikucki
P
P
Puchalski
A
A
Kankofer
M
M
D000818:Animals; D002417:Cattle / Q000097:blood / Q000276:immunology*; D005098:Exotoxins / Q000276:immunology*; D006854:Hydrocortisone / Q000097:blood; D016978:Mannheimia haemolytica / Q000276:immunology*; D013312:Stress, Physiological / Q000097:blood / Q000276:immunology* / Q000662:veterinary*; D014195:Travel
D005098:Exotoxins; C018579:leukotoxin; D006854:Hydrocortisone