Changes in Seasonal Egg Production of Turkeys Induced Through Controlled Light Exposure and Force Moulting

Effect of Light Regime and Age on Reproduction of Turkeys ,

“…In general this study was in agreement with the observations of Piatt (1955) in regard to chickens and with those of Marr et al (1956) and Harper and Parker (1957) in regard to turkeys, who indicated that initial egg production was higher in birds which were preconditioned to restricted light followed by 14 or more hours of continuous daily light. However, the results are not in agreement with the latter two investigations in regard to total egg production.…”

“…Similar conclusions were obtained by Burger (1947), Damste (1947), Wolfson (1952, and Callenbach et al (1944) regarding the response in other species of birds. They are also in Harper and Parker (1957) with Beltsville Small White turkeys.…”

Photoperiodism as a Factor in the Reproduction of the Turkey

“…The preliminary work of Harper and Parker (1957) tends to support this theory. Marr et al (1956), comparing performance of turkeys at different seasons of the year, observed better subsequent egg production from females hatched in January that were subjected to an 8-hour day from 14 or 16 to 28 or 30 weeks of age and then exposed to a 14-hour day during the reproductive period.…”

Effect of photoperiod on gonadotrophin concentrations in domestic turkeys

“…Since the gonads are small during the photorefractory state it is probable that feedback from gonadal steroids is low and might lead to increased pituitary gonadotrophin synthesis and the differential release of LH. Support for this comes from reports of progesterone causing moult in turkeys and the domestic fowl and the inhibition of this process by oestrogen and testosterone in the domestic fowl (Juhn and Harris, 1956;Harper and Parker, 1957;Payne, 1972). The exact cause of moult remains to be elucidated but it may be due to a hormone imbalance (Payne, 1972).…”