Brown egg layers fed low density diets perform better in barn than in cages.

Abstract

26A Brown egg layers fed low density diets perform better in barn than in cages Y.L. Henuk and J.G. Dingle School of Animal Studies, University of Queensland, Gatton Qld 4345 ylh@sas.uq.edu.au Barn hens typically consume 120_135 g/d, 8_20% more than caged hens which consume approximately 100_120 g/d (Lu and Dingle 1999). The additional feed intake might be due to an increased requirement for energy and so this 7_week experiment compared the responses by cage_ and barn_layers to a standard diet with their responses to a less nutrient_dense diet. The 288 ISA Brown layers aged 40 weeks that were used had been reared on litter and were placed at 22 weeks of age in cages, or in a barn system with tube feeders, nest boxes and a perch. They were fed a commercial laying ration. At 39 weeks of age, the birds in each system were randomly divided into two groups, and four replicates of 18 hens in each group received: (i) the control diet (T1) that contained (g/100g) 66.54 maize meal, 7.21 lucerne meal, 7.01 cottonseed meal, 0.64 rapeseed meal, 7.0 fish meal, 3.11 sunflower oil, 8.25 limestone, and 0.24 salt, and was formulated to contain 15.0% CP, 12.0 MJ ME/kg, 3.25% Ca, and 0.25% available P; or (ii) the less nutrient dense diet (T2) which consisted of the T1 diet and maize meal in the proportions 88:12. The T2 diet was $10/t cheaper than T1. Overall, the feed intakes were at the low end of the usual ranges so that the daily protein intakes of the cage birds were below the recommended 16.5 g/d for brown egg layers (NRC 1994). The feed intakes of barn birds were significantly greater than those of cage birds, possibly because of greater physical activity. They had significantly higher intakes of protein and ME than the cage birds; their egg production, egg weight, and yolk colour were also significantly greater, but not optimum. In general, there were no significant differences within each system between the T1 and T2 diets which could both be termed low density. The trial showed that barn birds performed better than cage birds when fed low density diets. Lu, C.C. and Dingle, J.G. (1999). Comparison of the performance of laying hens in cage, barn or free range systems. In: Proceedings of the Queensland Poultry Science Symposium, 8(6), 1_6 (ed. J.G. Dingle), University of Queensland, Gatton, Qld. National Research Council. (1994). Nutrient Requirements of Poultry. 9th Revised Edition. National Academy Press, Washington, D.C., USA. Table 1 Feed intakes and egg production by hens in cages or bar n given diets T1 and T2. Cages T1 Feed intake (g/bird/d) Protein intake (g/bird/d) ME intake (MJ/bird/d) Egg production (%) Egg weight (g) Feed conversion ratio (g/g) Egg specific gravity (g/cc) Haugh units Yolk colour (Roche Fan) 100. 8 b Barn T2 99.1 14.1 b b c SEM T2 123.5a 17.6 a a T1 122.9 18.4 a a b 1.56 0.30 0.24 2.01 0.60 0.06 0.0008 0.02 0.03 15.1b 1.17d 61.3b 64.0 b 1.29 59.1 64.3 b b 1.47 73.4 66.9 a a 1.60 68.8 67.1 a a 2.59 1.0880 86.7 10.8 b 2.64 1.0892 86.8 10.7 b 2.54 1.0899 86.8 11.1 a 2.71 1.0893 86.8 11.2 a Within rows means with different superscripts differ significantly (P<0.05) Recent Advances in Animal Nutrition in Australia, Volume 13 (2001)