Periparturient equidae are particularly susceptible to hyperlipaemia, a severe metabolic disorder that can be induced and aggrevated by stressful situations. To define maternal endocrine and metabolic adaptations to the peripartum period, plasma concentrations of progesterone, oestradiol, 13,14-dihydro-15-keto-prostaglandin F 2 α (PGFM), triglyceride, cholesterol, glucose, total protein, urea, cortisol and insulin were examined in two donkey mares throughout late gestation (−50 days), parturition (Day 0) and early lactation ( + 100 days), and in one non-pregnant mare over six oestrous cycles. Maternal progesterone and oestradiol concentrations increased towards term, to maxima of 50–60 nmol 1 −1 and 130–170 pmol 1 −1 , respectively, and decreased rapidly from 2 days prepartum to < 5 nmol 1 −1 and < 15 pmol 1 −1 at parturition. Plasma PGFM concentrations of 8–11 nmol 1 −1 over 1 week prepartum decreased to < 1 nmol 1 −1 1 day postpartum. Maternal triglyceride concentrations increased from 1–2 nmol 1 −1 over late gestation to a maximum of 2–4 mmol 1 −1 at parturition. Thereafter, values rapidly decreased to <0.5 mmol 1 −1 by 3 days postpartum. Plasma cholesterol and total protein profiles also followed this pattern: no consistent changes were evident in glucose, urea, cortisol or insulin concentrations. To assess endocrine and metabolic responses to a stressor in animals under gestational or lactational energy demands, plasma cortisol, triglyceride, cholesterol, glucose and insulin concentrations were examined in the same two donkey mares transported for approximately 4 h at 3–10 weeks prepartum and 2–9 weeks postpartum. These responses were compared with those observed in non-pregnant donkeys. Transportation increased cortisol concentrations in pregnant (maximally by 215 and 130%), lactating (32 and 85%) and non-pregnant animals (145±9%). Plasma glucose concentrations remained stable in all but one lactating donkey; the hyperglycemic effect may have been an indirect indicator of a reduced tissue sensitivity to insulin. Stressor-induced suppression of circulating insulin was apparent in postpartum (−57 and −51%) and non-pregnant animals (−46 ± 4%). Triglyceride and cholesterol concentrations in all donkeys were unchanged by transportation. The observed shifts in lipid metabolism, possibly facilitated by gestational changes in concentrations of progesterone and oestradiol, are likely to make the peripartum mare vulnerable to the development of equine hyperlipaemia. However, an additional environmental stressor (4 h transportation), which stimulated an adrenocortical response in periparturient donkeys, was unable to induce any consistent alteration in metabolic function or evidence of potential dysfunction.