Performance of laying hens as affected by split time and split composition dietary regimens using ground and unground cereals

Abstract

1. A factorial experiment was conducted to study the effects on the performance of White Leghorn× Australorp laying hens of diets based on unground cereal grains, small morning and large afternoon meals, and morning and afternoon meals of different composition.

2. From 10 to 21 weeks of age the pullets' food intake was restricted, using either a diet in which the wheat fraction (600 g/kg) was unground or a fully ground diet of similar composition.

3. In the laying period the birds received either a diet (U) in which the limestone was granulated and most of the cereal fraction (wheat and oats or wheat and sorghum) was unground or a fully ground diet (G) of similar composition.

4. Both laying diets were offered ad libitum (A), with 25% issued in the morning and 75% in the late afternoon (T) or as a protein concentrate (250 g/kg of total diet) in the morning and cereal/limestone fraction (750 g/kg) in the late afternoon (C).

5. Rearing and laying performance were unaffected by rearing diet.

6. Laying diet U resulted in a 5.2% increase in food intake and a 0.9 g increase in average egg weight compared with diet G. From 21 to 56 weeks of age, when the cereal/limestone fraction of the diet included oats (240 g/kg of total diet), diet U resulted in fewer (4.8/bird) eggs and a lower financial margin than diet G. From 56 to 80 weeks of age, when oats were replaced by sorghum, this trend was reversed (—3.5 eggs).

7. Birds on diet C produced fewer (16.9) eggs of lower (1.5 g) average weight than birds on diet A, ate less (1.39 kg) food and had a lower financial margin. Diet T gave similar results to diet A, although from 56 to 80 weeks of age the birds of treatment GT produced fewer (8.7) eggs than those of treatment GA.

8. It is concluded that the split composition treatment used in this experiment reduced egg production and financial return, the split time treatment showed no advantage but, under conditions which permitted little or no dietary self‐selection, a diet consisting of unground wheat, unground sorghum, limestone grit and protein concentrate resulted in a higher egg number, egg mass and financial return than a fully ground diet.