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| == Photoperiod == | | == Photoperiod == |
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| + | The month of birth will influence the onset of puberty, especially in seasonal breeders. |
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| + | === Sheep === |
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| + | * 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. |
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| + | === Heifers === |
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| + | === Bitch === |
| + | |
| + | === Queen === |
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| == Genetics == | | == Genetics == |