Changes in somatic cell count and plasma cortisol concentration during three relocation trials in German Brown cows

German Brown dairy cows from the institute's herd (loose housing, slatted concrete floor, chopped straw cubicles) in overall good condition of udder health and management were assigned to 3 successive experiments in different seasons of the year. All 3 experiments were based on a 1 or 2 week lasting relocation phase to an unfamiliar stanchion barn (long stalls with straw bedding) combined with transportation. Quarter foremilk samples were taken each morning for determination of SCC. In the first experiment, mainly cows with chronically elevated SCC in the familiar loose housing system were used (n=4), in the second experiment cows were randomly assigned (n=8). During the third experiment (n=8), randomly selected cows (3 of 8) were additionally provided with indwelling catheters in the jugular vein for determination of mean plasma cortisol concentration before and after the respective relocations. Results showed a highly significant and reversible decrease (p < 0.001) in quarter foremilk SCC of each ani7 mal during the relocation phase, which could not be linked to immunosuppressive levels of plasma cortisol concentration. Neither was any influence of bacteriological status, season, age, stage of lactation or nutrition to be calculated. These results provide additional evidence that significant changes in SCC may be caused by environmental factors other than by infection.