Some factors affecting albumen quality with particular reference to Haugh unit score

Abstract

Excluding disease, the single most important factor affecting the albumen quality of the freshly laid egg is the age of the bird that laid it. With advancing flock age, Haugh unit scores decrease and the variability of the scores increases. An induced pause in egg production is beneficial in largely restoring albumen quality in aging hens. Both strain differences and strain/age interaction effects in Haugh unit scores of fresh eggs have often been observed, but these are normally small and have little practical significance. Albumen quality of the egg is not greatly influenced by bird nutrition. Environment and housing, even heat stress, appear to have almost no direct effect on the albumen quality of the egg at oviposition.When ambient temperatures are high, delays in egg collection and/or cooling increase the rate of Haugh unit score decline. The maintenance of albumen quality during egg storage is dependent on the eggs being cooled quickly following lay and subsequently being held at low temperatures, preferably down to, but not below, 0°C. Oiling of eggs within 24 h of lay is very effective in retarding deterioration of the albumen but does not replace the need for cool storage. Information on genetic effects on the albumen quality of stored eggs is equivocal, although there is general agreement that any effects are small and of little commercial significance. Of greater importance is the finding that within strains there can be great variation in Haugh unit scores and that strains laying white-shelled eggs are much less variable than those producing brown-shelled eggs.