Changes

* The age that the female becomes sexually receptive and displays the first [[Oestrus Behaviour - Anatomy & Physiology|oestrus]].

* The age that the female becomes sexually receptive and displays the first [[Oestrus Behaviour - Anatomy & 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 [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]] is usually not accompanied by behavioural [[Oestrus Behaviour - Anatomy & Physiology|oestrus]] in heifers and ewes and is hence termed 'silent ovulation'.  Thus, the age at first [[Oestrus Behaviour - Anatomy & Physiology|oestrus]] may not accurately reflect acquisition of puberty.

* The first [[Ovulation - Anatomy & Physiology|ovulation]] is usually not accompanied by behavioural [[Oestrus Behaviour - Anatomy & Physiology|oestrus]] in heifers and ewes and is hence termed 'silent ovulation'.  Thus, the age at first [[Oestrus Behaviour - Anatomy & Physiology|oestrus]] may not accurately reflect acquisition of puberty.

== Age at First Ovulation ==

== Age at First Ovulation ==

* The age at which [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]] first occurs.

* The age at which [[Ovulation - Anatomy & Physiology|ovulation]] first occurs.

* Manual or visual validation is required. This can be accomplished by palpation of the [[Ovary - Anatomy & Physiology|ovary]] per [[Rectum_- Anatomy & Physiology|rectum]] in animals that are large enough to permit insertion of a hand/arm into the [[Rectum_- Anatomy & Physiology|rectum]] (cow and camelids).

* Manual or visual validation is required. This can be accomplished by palpation of the [[Ovary - Anatomy & Physiology|ovary]] per [[Rectum_- Anatomy & Physiology|rectum]] in animals that are large enough to permit insertion of a hand/arm into the [[Rectum_- Anatomy & Physiology|rectum]] (cow and camelids).

* Ultrasound can be used most successfully in the mare to determine ovarian status.

* Ultrasound can be used most successfully in the mare to determine ovarian status.

* When [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]] has occured, a soft depression on the surface of the [[Ovary - Anatomy & Physiology|ovary]] can be palpated.

* When [[Ovulation - Anatomy & Physiology|ovulation]] has occured, a soft depression on the surface of the [[Ovary - Anatomy & Physiology|ovary]] can be palpated.

* In smaller animals (sow, ewe, bitch, queen) surgical procedures are necessary to allow visualisation of the [[Ovary - Anatomy & Physiology|ovary]] in order to determine [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]].  In addition laparoscopic observation can be used to determine when [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]] occurs.

* In smaller animals (sow, ewe, bitch, queen) surgical procedures are necessary to allow visualisation of the [[Ovary - Anatomy & Physiology|ovary]] in order to determine [[Ovulation - Anatomy & Physiology|ovulation]].  In addition laparoscopic observation can be used to determine when [[Ovulation - Anatomy & Physiology|ovulation]] occurs.

* All techniques require frequent observation of the [[Ovary - Anatomy & Physiology|ovary]], so although age at [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]] is a good criterion for puberty, it is difficult to determine.

* All techniques require frequent observation of the [[Ovary - Anatomy & Physiology|ovary]], so although age at [[Ovulation - Anatomy & Physiology|ovulation]] is a good criterion for puberty, it is difficult to determine.

== Age at which the Female can Support Pregnancy without Deleterious Effects ==

== Age at which the Female can Support Pregnancy without Deleterious Effects ==

* Most practical definition in all domestic animals.

* Most practical definition in all domestic animals.

* Acquisition of a threshold body size is important in controlling onset of puberty.

* Acquisition of a threshold body size is important in controlling onset of puberty.

* Energy requirements for follicular development and [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]] are small, however the metabolic cost of pregnancy and lactation are high so the female must reach a 'metabolic threshold' before puberty can occur.

* Energy requirements for follicular development and [[Ovulation - Anatomy & Physiology|ovulation]] are small, however the metabolic cost of pregnancy and lactation are high so the female must reach a 'metabolic threshold' before puberty can occur.

[[Category:Reproductive System]]

[[Category:Reproductive System]]