Adrenal responsiveness in pre- and postpartum dairy cows

Area of Science:

• Veterinary Endocrinology
• Reproductive Physiology
• Dairy Science

Background:

• Adrenal function is crucial for managing physiological stress in dairy cows, particularly around parturition.
• Understanding adrenal responsiveness is key to managing cow health and productivity during the transition period.

Purpose of the Study:

• To evaluate adrenal responsiveness in multiparous dairy cows during the prepartum and postpartum periods.
• To assess the relationship between adrenal function and changes in glucocorticoid, estradiol, and progestin concentrations.

Main Methods:

• Adrenocorticotropin (ACTH) injections were administered to 10 dairy cows at three different times: late prepartum, early postpartum, and later postpartum.
• Plasma glucocorticoid concentrations were measured at various time points post-injection.
• Concentrations of estradiol and progestins were also monitored throughout the sampling periods.

Main Results:

• Adrenal responsiveness, measured by glucocorticoid response to ACTH, was not significantly different across the three injection periods.
• Glucocorticoid levels peaked around calving and remained elevated for two days postpartum.
• Estradiol levels surged by calving, while progestins declined prepartum, with no observed impact on adrenal responsiveness.

Conclusions:

• Dairy cows exhibit well-maintained adrenal potential during the prepartum and postpartum transition.
• Parturition-induced hormonal shifts do not appear to alter the adrenal gland's responsiveness to stimulation.
• Adrenal function remains robust despite significant physiological changes associated with calving.