twenty minutes after the last animal was head-locked, the first basal blood
sample was taken from the coccygeal vein by a single operator. The cows were then
randomly divided into two groups. A second blood sample was taken from the coc-
cygeal vein of animals in the control group (CG,
n
= 5) after a 20 min rest period. The
cows remained in the head-locks and were approached as calmly as possible by the
same operator in order to minimise stress.