Effect of restricting the energy intake of the laying hen, directly and by dilution of the diet, on egg production and the efficiency of energy utilisation.

Abstract

AbstractAn experiment is described in which the daily metabolisable energy (ME) intake of light and medium weight hybrid pullets fed a concentrated diet (ME = 3720 kcal/kg) was restricted directly on an individual hen basis (95, 85 and 75 g/day) and also by dilution of the diet using wood dust as the diluent (13.6, 22.7 and 31.8% wood dust). The concentrated diet and a high‐energy diet (ME = 2750 kcal/kg) were also fed ad libitum.Total egg weight and percentage egg production were not significantly different for hens fed the concentrated diet ad libitum, at the first two levels of restriction or at the lowest level of dilution.Both direct restriction and restriction by dilution of the diet resulted in greatly reduced liveweight gains.Direct restriction of the ME intake resulted in a marked improvement of ME conversion to egg product (Mcal/kg eggs).Dilution of the diet had a detrimental effect on the ME conversion.Calculations, based on calorimetric data, of the ME requirement for maintenance and production (eggs plus bodyweight gain) showed that direct restriction resulted in observed ME intakes which, although higher, were closer to the calculated ME requirements than did ad libitum feeding. Restriction of ME intake by dilution of the diet resulted in the actual ME intakes being much greater than the calculated requirements, the difference being 70 and 50% of the calculated ME requirements at the 31.8% level of dilution for the light and medium hybrids, respectively.The possible reasons for the difference between the calculated ME requirements based on calorimetric data and the observed ME intakes obtained in the practical laying trial are discussed.