* 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 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 [[The_Ovary_-_Ovulation_-_Anatomy_%26_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.