scholarly journals Effect of Lighting Program and Nutrition on Reproductive Performance of Molted Single Comb White Leghorn Hens ,

1987 ◽  
Vol 66 (8) ◽  
pp. 1298-1305 ◽  
Author(s):  
D.K. ANDREWS ◽  
W.D. BERRY ◽  
J. BRAKE
1997 ◽  
Vol 76 (2) ◽  
pp. 236-243 ◽  
Author(s):  
ED Peebles ◽  
EH Miller ◽  
CR Boyle ◽  
JD Brake ◽  
MA Latour ◽  
...  

1972 ◽  
Vol 51 (1) ◽  
pp. 313-320 ◽  
Author(s):  
J.A. Asmar ◽  
P.L. Pellett ◽  
Nur Hariri ◽  
M.D. Hariri

1951 ◽  
Vol 2 (4) ◽  
pp. 494
Author(s):  
F Skaller ◽  
GW Grigg

Evidence has been presented in the literature on the mode of inheritance of shank colour in various breeds of chickens, but little has hitherto been known about the same aspect in an Australian breed, the Black Australorp. Observations on the incidence of shank colour in different types of crosses between yellow-shanked White Leghorns and black-shanked Australorps are reported in this paper. According to the observations made by other workers on White Leghorn and other breeds, a hypothesis is advanced regarding the genes involved in determining shank colour in the White Leghorn and Australorp. A genetical analysis of the observations made by the authors on 847 single crosses, 71 backcrosses, and 31 zig-zag crosses is presented and shows close statistical agreement with the hypothesis. A genetical formula, including four autosomal and two sex-linked genes, is suggested which would explain the mode of inheritance of shank colour in White Leghorns and Australorps.


1989 ◽  
Vol 69 (3) ◽  
pp. 757-764 ◽  
Author(s):  
S. LEESON ◽  
L. J. CASTON ◽  
J. D. SUMMERS

Three experiments were undertaken to investigate the coccidiostat, nicarbazin, on reproductive performance of layers. In trial 1, levels of 0, 5, 10, 20, 40, 80, 125, and 200 ppm nicarbazin were fed to White leghorn laying hens for 5 wk. By the 2nd week of nicarbazin treatment, egg production was significantly reduced in birds fed 125 and 200 ppm (P < 0.05). Similarly, increasing levels of nicarbazin resulted in decreasing egg weights (P < 0.01) and feed intake was significantly decreased. However, by the 2nd week post-nicarbazin treatment, egg production, egg weight, and feed intake had returned to normal. Nicarbazin had no effect on egg shell deformation or body weight. Nicarbazin had a marked effect on hatchability; levels of 125 and 200 ppm reduced hatchability significantly (P < 0.01) as well as producing an increased incidence of malpositions and malformations. When nicarbazin was withdrawn from the diet, hatchability returned to pretreatment values although malpositions and malformations were still in evidence. Experiments 2 and 3 were designed to study the effect of nicarbazin on production of brown-shelled eggs. In the 2nd experiment 0, 5, 10, 20, and 40 ppm of dietary nicarbazin resulted in significant loss of shell color at 20 and 40 ppm, whereas in exp. 3 with levels of 0, 80, 125, and 200 ppm, brown eggs lost virtually all their color. It is concluded that the adult White Leghorn bird can tolerate up to 125 ppm nicarbazin without significant (P < 0.01) loss of reproductive performance although lower levels show a trend for reduced production. Hatchability is depressed with nicarbazin levels in excess of 80 ppm, while trace levels will produce a visual loss of color in brown-shelled eggs. Key words: Layer, coccidiostat, reproductive performance


2008 ◽  
Vol 45 (1) ◽  
pp. 31-38 ◽  
Author(s):  
James Tyus II ◽  
Samuel N. Nahashon ◽  
Nathaniel Adefope ◽  
Darren Wright

Sign in / Sign up

Export Citation Format

Share Document