Changes

==Introduction==

==Introduction==

Unlike polyoestrus animals such as the cow or sow which can reproduce all year round some species such as the Mare, Ewe, Goat, Rabbit, Hampster and Doe have an '''Anoestrus''' phase to their reproductive cycling. This means that for part of the year they are not experiencing oestrous cyclicity and so are not reproductively active. Such animals can be long or short day polyoestrus breeders. Seasonality of reproduction is due to the effect of light levels on the brain. Reproductive seasonality maximises the chance of offspring survival by timing parturition to coinside with spring when nutritional and climate conditions are optimum for lactation and for growth of the offspring. It is important to be able to distinguish between seasonal anoestrus and pathological infertility. Both males and females exhibit reproductive seasonality. However, the female is more strongly influenced by season.

Unlike polyoestrus animals such as the cow or sow which can reproduce all year round some species such as the mare, ewe, goat, rabbit, hamster and doe have an '''anoestrus''' phase to their reproductive cycling. This means that for part of the year they are not experiencing oestrous cyclicity and so are not reproductively active. Such animals can be long or short day polyoestrus breeders. Seasonality of reproduction is due to the effect of light levels on the brain. Reproductive seasonality maximises the chance of offspring survival by timing parturition to coincide with spring when nutritional and climate conditions are optimum for lactation and for growth of the offspring. It is important to be able to distinguish between seasonal anoestrus and pathological infertility. Both males and females exhibit reproductive seasonality. However, the female is more strongly influenced by season.

==Mechanism of seasonality==

==Mechanism of seasonality==