The effects of mating on the sexual receptivity of female alpacas

Abstract

To describe changes in the sexual receptivity of female alpacas (hembras) following mating, hembras were either mated on Day 0 ( n=7) or remained unmated as a control ( n=7). The sexual receptivity of hembras was tested on Days 0–9, by confining each hembra separately in a pen with a male alpaca (macho) for 30 s. Laparoscopic determination of ovarian activity on Day 6 revealed that a corpus luteum was present in four of six of the mated hembras. The two remaining hembras and four of the unmated animals had luteinised and antral follicles. The remaining three unmated hembras had antral follicles only. Mated hembras spat, kicked, vocalised and attempted to escape from the testing pen during more of the receptivity tests than control hembras ( P<0.05). Spitting and attempting to escape were also more prevalent in hembras with a corpus luteum than in those with luteinised or antral follicles ( P<0.05). Despite the widely held belief that hembras adopt a position of ventral recumbency if they are sexually receptive, no relationship between this behaviour and mating behaviour or ovarian status was found, perhaps because the testing procedure caused stress-induced sitting.