Changes

* The age that the female becomes sexually receptive and displays the first [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]].

* The age that the female becomes sexually receptive and displays the first [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]].

* Easy to determine because females show outward behavioural signs of sexual receptivity, especially in the presence of a male.

* Easy to determine because females show outward behavioural signs of sexual receptivity, especially in the presence of a male.

* The first ovulation is usually not accompanied by behavioural [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]] in heifers and ewes and is hence termed 'silent ovulation'.  Thus, the age at first [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]] may not accurately reflect acquisition of puberty.

* The first [[The_Ovary_-_Ovulation_-_Anatomy_%26_Physiology|ovulation]] is usually not accompanied by behavioural [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]] in heifers and ewes and is hence termed 'silent ovulation'.  Thus, the age at first [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]] may not accurately reflect acquisition of puberty.

== Age at First Ovulation ==

== Age at First Ovulation ==