ABSTRACT

An experiment in a completely Randomized design with six replicates was used to study: 'the responses of old layers

(Lohmann breed) of 128 weeks of age which have been in lay for 106 weeks (2 years) to moult induction using a combination of feed withdrawal, water withdrawal and light restriction for 14 days; the effect of period. (morning hours and afternoon hours) on the economic pararneiers of the resultant eggs postnioulting; and the effect of storage under room temperatures and conditions on the eggs laid in the morning hours and the eggs laid in the afternoon hours. rrle birds were distributed into 7 pens, each containing 15 birds. One of the pens served as the control. Egg collection lasted for 6 weeks with each week as a replicate. The study was conducted at Michael Okpara University of Agriculture, Umudike, Ahia State, Nigeria between November, 2001 and May, 2002. Attributes studied were: egg production responses due to moult induction, mortality due to moult induction, ovary weight, oviduct weight, liver weight, egg weight, egg length, egg width, egg shape index, egg specific gravity, yolk weight, yolk diameter, yolk height, yolk index, albumen weight, albumen height, shell weight, shell thickness, shell percentage, albumen percentage, yolk percentage, moisture loss at storage and Haugh Unit. The results show that in absolute values morning eggs were higher than afternoon eggs and showed significant difference (P<0.05) in egg weight (60+0.4 and 57.3+0.78g, respectively) egg length(5 .85 + 0.02 and 5.7+0.016cm, respectively) egg width (4.39+0.008 and 4.3+0.015cm, respectively) egg shape index (0.75+0.01 and 0.76+0.008, respectively), and I-laugh unit (92.17+2.6 and 88.25 +2.04, respectively); and that storage affected the egg weights (59.5+2.11 and 53.6+1.86g, respectively), haugh units (83.37+ 1.47 and 85.3 +2.66, respectively), albumen height (0.73 +0.02 and 0.67 +0.03cm, respectively and egg yolk index (0.313+0.03 and 0.29+0.005, respectively). There were no significant differences (P >0.05) between the egg parameters of morning and afternoon eggs during storage with the exception of albumen and egg weights. The results show that forced moulting can be used by Nigerian farmers under Nigerian climates to rejuvenate and recycle their spent layers to lay.