Estrus: [noun= estrus; adi.= estrous; also: oestrus/ oestrous] [see also: Diestrus, pre-estrus, Metestrus, reproductive cycling] (Hess e/ al. 7983; Moss 1983: 179,180-181; Buss 1990:111-114; Poole 1994:336; Brown 2000:348) Period of "heat" . in females; associated with ovulation and the time that conception is most likely to occur. Only duing this period do females permit copulation by males; they usually show a preference for older males, especially those in Musth. Estrus cycles are approximately 12-17 weeks (85-120 days) in sexually mattrie, non-pregnant females, and the estrous period usually lasts 2-6 days. In captivity estrus can be detected by a Progesterone surge in the blood around the time of ovulation.
