Behavioral dominance and corpus luteum function in red deer Cervus elaphus

Area of Science:

• Reproductive Biology
• Animal Behavior
• Endocrinology

Background:

• Social hierarchy and dominance can influence physiological processes in animals.
• Understanding reproductive endocrinology in wild or semi-wild populations is crucial for conservation and management.

Purpose of the Study:

• To investigate the relationship between social dominance status and the timing of the ovulatory luteinizing hormone (LH) surge.
• To characterize progesterone concentration profiles post-ovulation in relation to dominance in red deer hinds.
• To explore potential links between social status, reproductive events, and calf sex determination.

Main Methods:

• Synchronized ovulation in red deer hinds using hormonal treatments.
• Determined social status through observation of agonistic interactions.
• Monitored estrus, LH surge timing, and daily progesterone levels via blood sampling.
• Analyzed weight changes and correlated reproductive parameters with dominance status.

Main Results:

• A significant relationship was found between weight change and dominance status in Experiment 2 (p < 0.01).
• The rate of increase in progesterone post-ovulation was significantly related to social status (p < 0.02).
• Estrus timing (mating) was not correlated with dominance status when a stag was present.

Conclusions:

• Social status significantly affects corpus luteum function in red deer hinds, as indicated by progesterone profiles.
• Dominance hierarchy may play a role in modulating reproductive success and potentially influencing offspring sex ratio.
• Further research is warranted to elucidate the mechanisms linking social status to reproductive outcomes.