Introduction
Acute stress has detrimental effects on ovarian cyclicity by
disrupting the normal release of hormones from the hypothalamus-
pituitary-ovarian axis that normally control reproduction
(Dobson et al., 2003; Smith et al., 2003). This disruption,
resulting in suppression of pulsatile release of luteinising
hormone from the pituitary, may impact on ovarian progesterone
and estradiol concentrations, hormones that are necessary
for the expression of sexual behavior (Allrich, 1994). More
long-term chronic stress also impairs reproductive function in
rats (Rivier and Rivest, 1991). Lameness in dairy cows could be
used as a model for a biologically occurring chronic stressor as