Behavioral dominance and corpus luteum function in red deer Cervus elaphus.
Times of the ovulatory LH surge and characteristics of the rise in circulating progesterone concentrations after ovulation in red deer hinds were investigated in relation to each animal's dominance status. Observations were made during the 1992 (experiment 1) and 1993 (experiment 2) breeding seasons, while the same 12 hinds were held in a pen in the absence of a stag. Ovulation was synchronized by administration of progesterone followed by luteolytic prostaglandin F2 alpha analogue. Social status was determined for each hind by noting dyadic agonistic interactions during the period of progesterone treatment. Hinds were weighed before and after the experiments. Time of onset of estrus (lordosis) was recorded while handling at 3-hr intervals (for 81 hr in experiment 1; 96 hr in experiment 2) after progesterone withdrawal, and blood samples were collected at these times to characterize the preovulatory LH surge. Subsequently, daily blood samples were collected for up to 11 days for measurement of progesterone concentrations. There was a tendency for weight change to be related to dominance status in experiment 1 and this was significant in experiment 2 (p < 0.01). The rate of increase in circulating progesterone concentration after ovulation was related to status (data of experiments 1 and 2 combined; p < 0.02), but was not correlated with the time of estrus or with the time or height of the LH surge. A third experiment (carried out in 1993), when the same hinds were kept with a stag after induced ovulation, showed that time of estrus (mating) was not related to dominance status. The data suggest that corpus luteum function is affected by social status. The results are discussed in the context of mechanisms by which dominance status influences the sex of a hind's calves.
Flint
A P
AP
Institute of Zoology, Regent's Park, London, United Kingdom.
Albon
S D
SD
Loudon
A S
AS
Jabbour
H N
HN
D000818:Animals; D003338:Corpus Luteum / Q000502:physiology*; D003670:Deer / Q000502:physiology*; D004971:Estrus / Q000502:physiology; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010060:Ovulation / Q000502:physiology; D011374:Progesterone / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012930:Social Dominance
D011374:Progesterone; D007986:Luteinizing Hormone