Orientation of the Egg at Laying - Is the Pointed or the Blunt End First?
DOI:
https://doi.org/10.3923/ijps.2014.316.318Keywords:
Domestic duck, domestic goose, double yolked egg, egg laying, egg orientationAbstract
While the avian egg is formed in the oviduct, it acquires its shell membranes and shape in the isthmus and the calcified shell in the shell gland/uterus. However, in domestic species not all eggs are laid pointed end first, which led to the suggestion that egg rotation can occur in the oviduct prior to laying producing the blunt end first. However, not all studies were in agreement as to which end the pointed or the blunt-comes out first. Here, opportunistic observation of laying behaviour in domestic geese and ducks was carried out. 89.47% of the single yolked (SY) goose eggs were laid pointed end first. Goose age and dimensions did not influence the orientation of the egg, though the 12 blunt end first eggs were heavier and wider. 85.52% of the SY duck eggs were laid pointed end first. However, in double yolked (DY) duck eggs evidence was presented showing that the yolks closer to the airspace (blunt end) tend to be heavier (Salamon and Kent, 2013a) and had higher levels of fertilization (Salamon and Kent, in press) consistent with the yolk at the blunt end of the egg being ovulated first and suggests that the blunt end of these large eggs was caudal in the oviduct during egg formation. Questions remain to be answered.
References
artelmez, G.W., 1918. The relation of the embryo to the principal axis of symmetry in the bird's egg. Biol. Bull., 35: 319-361.
Bradfield, J.R.G., 1951. Radiographic studies on the formation of the hen's egg shell. J. Exp. Biol., 28: 125-140.
Curtis, M.R., 1916. Studies on the physiology of reproduction in the domestic fowl, XVI. Double eggs. Biol. Bull., 31: 181-212.
Kent, J.P. and K.J. Murphy, 2003. Synchronized egg laying in flocks of domestic geese (Anser anser). Applied Anim. Behav. Sci., 82: 219-228.
Lewin, V., 1963. Reproduction and development of young in a population of California quail. Condor, 65: 249-278.
Olsen, M.W. and T.C. Byerly, 1932. Orientation of the hen's egg in the uterus and during laying. Poult. Sci., 11: 266-271.
Romanoff, A.L. and A.J. Romanoff, 1949. The Avian Egg. John Wiley and Sons Inc., New York.
Romanov, M.N., 1999. Goose production efficiency as influenced by genotype, nutrition and production systems. World's Poult. Sci. J., 55: 281-294.
Salamon, A. and J.P. Kent, 2013. Double and single yolked duck eggs: Their contents and dimensions compared and the mechanical stimulation hypothesis for albumen secretion is supported. Int. J. Poult. Sci., 12: 254-260.
Salamon, A. and J.P. Kent, 2013. Egg weight declines to baseline levels over the laying season in domestic geese (Anser anser domesticus). Int. J. Poult. Sci., 12: 509-516.
Salamon, A. and J.P. Kent, 2014. Yolk size and ovulation order determine fertility within double yolked duck (Anas platyrhynchos domesticus) eggs. Reprod. Fert. Dev., (In Press).
Wood-Gush, D.G.M. and A.B. Gilbert, 1969. Observations on the laying behaviour of hens in battery cages. Br. Poult. Sci., 10: 29-36.
Downloads
Published
Issue
Section
License
Copyright (c) 2014 Asian Network for Scientific Information
This work is licensed under a Creative Commons Attribution 4.0 International License.
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
