Changes

* Secretions from the female reproductive tract that serve to sexually stimulate and attract males to the female.

* Secretions from the female reproductive tract that serve to sexually stimulate and attract males to the female.

* Vaginal and urinary secretions from females in '''Oestrus''' smell different to the male then secretions of females not in Oestrus.

* Vaginal and urinary secretions from females in '''Oestrus''' smell different to the male then secretions of females not in Oestrus.

* Pheramone is a volatile substance released to the outside of the body and perceived by the olfactory system and/or activated by the vomeronasal organ.  Releasing pheramones can cause specific behaviour in the recipient.

* Pheramone is a volatile substance released to the outside of the body and perceived by the olfactory system and/or activated by the '''vomeronasal organ'''.  Releasing pheramones can cause specific behaviour in the recipient.

* Males also produce sex pheramones.

* Males also produce sex pheramones.

** Boars produce specific substances that cause sows and guilts to become sexually aroused when they are in '''oestrus'''.

** '''Boars''' produce specific substances that cause sows and guilts to become sexually aroused when they are in '''oestrus'''.

** Two sexual attractants are produced by boars:

** Two sexual attractants are produced by boars:

*** Preputial pouch secretion

*** '''Preputial pouch secretion'''

*** Pheramonal substance in saliva secreted by the submaxillary salivary gland.

*** '''Pheramonal substance in saliva''' secreted by the submaxillary salivary gland.

**** During sexual excitement, the boar produces copious quantities of foamy saliva.  The active components in saliva are the androgen metabolites 3

**** During sexual excitement, the boar produces copious quantities of foamy saliva.  The active components in saliva are the androgen metabolites '''3α-Androstenol''' and '''5α-Androstenone'''.  Both have a musk-like odour.