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Puberty Onset Influencing Factors - Anatomy & Physiology (view source)
Revision as of 14:18, 8 September 2008
, 14:18, 8 September 2008→Photoperiod
== Photoperiod ==
== Photoperiod ==
The month of birth will influence the onset of puberty, especially in seasonal breeders.
=== Sheep ===
* Short day breeders (begin oestrous cycles in response to short day length)
* Spring born lambs (February-March) reach puberty in the subsequent autumn (September-October) if they have adequate nutrition. The age at puberty is 5-6 months.
* Autumn born lambs do not reach puberty until 10-12 moths of age.
* This is because, seasonal cues (long days of spring/summer) delay reproductive cyclicity.
* Thus, oestrus in both spring and autumn born lambs is synchronised.
* This maximizes the chance that all ewes become pregnant in the fall and give birth in the spring when nutritional and environmental conditions are favourable.
* An adequate degree of nutrition ('fatness') is required before photoperiod can exert an effect.
=== Heifers ===
=== Bitch ===
=== Queen ===
== Genetics ==
== Genetics ==