Effects of photoperiod and intermittent lighting on reproduction in pheasant hens

Effect of different egg storage times on some egg quality characteristics and hatchability of pheasants (Phasianus colchicus)

“…In this study there was no significant effect of storage time on egg weight. Egg weight values were similar to those reported by Woodard et al (1983), 30.6 g; Blake et al (1987), 31.9 to 34.4 g; Slaugh et al (1988), 31.00 to 32.3 g; Tserveni-Gousi and Yannakopoulos (1990), 30.49 g; Yannakopoulos (1992), 33.99 g; Çetin et al (1997) 33.36 g; Kırıkçı et al (2003b), 31.03 g; Günlü et al (2007), 30.22 to 32.19 g; and also Kırıkçı et al (2005), 31.89 and 31.16 g for brown and green eggs, respectively. However, the egg weights in the present study were higher than the values of 28.1 to 29.5 g reported by Woodard and Snyder (1978) and 25.79 g The differences between values with different superscript letters in the same column are significant (P < 0.05).…”

“…Storage time did not significantly affect fertility ratio values. Fertility ratio determined in with the present study is similar to fertility ratios reported in previous studies (Woodard et al, 1983;Mashaly et al, 1983;Bates et al, 1987;Blake et al, 1987;Slaugh et al, 1988;Yannakopoulos, 1992;Çetin et al, 1997;Wadland, 2001, 2002;Kırıkçı et al, 2003b).…”

Light increases the rate of embryonic development: implications for latitudinal trends in incubation period

“…After development of the pineal gland, pulses of light during adult recesses may register as complete photoperiods to embryos. It is widely established that brief periods of light to signal the beginning of the day and another to signal the end of the day, called skeleton photoperiods or intermittent lighting, can be interpreted by birds as a 'subjective day' (Bacon 1984;Rowland 1985) and entrain physiological processes (Slaugh et al 1988). It is conceivable that the incubation patterns of birds could create a skeleton photoperiod by exposing eggs to brief pulses of light, essentially defining a subjective day.…”

Solar noon and tactile cues synergistically regulate clutch size: a new approach to investigations of avian life‐history theory

“…, Slaugh et al . ). However, egg removal experiments have provided ample evidence that the tactile stimulation of eggs in the nest triggers disruptions of the ovulatory cycle and thus termination of the laying sequence (Klomp , Kennedy , Haywood ).…”

“…To understand regulation of clutch size it is therefore necessary to understand what triggers the onset of the hormone cycles governing the timing of the surges that create the permissive zone and the sequence of ovulations, and then to identify the signal, or signals, that disrupt the cycles to terminate the laying sequence. Since photoperiod is known to influence the function of the circadian clocks governing the pulsatile hormone surges, there should be some correlation between day-length, frequency of ovulation, and termination of the ovulatory cycle (Fraps 1955, Johnson & van Tienhoven 1980, Etches et al 1984, Johnson et al 1985, Slaugh et al 1988). However, egg removal experiments have provided ample evidence that the tactile stimulation of eggs in the nest triggers disruptions of the ovulatory cycle and thus termination of the laying sequence (Klomp 1970, Kennedy 1991, Haywood 1993a).…”