Comparison between Laying Hen Performance in the Cage System and the Deep Litter System on a Diet Free from Animal Protein

Voslafiova E. , Z. Hanzalek, V. Veaerek, E. Strakova, P. Such : Comparison between Laying Hen Performance in the Cage System and the Deep Litter System on a Diet Free from Animal Protein. Acta Vet. Brno 2006, 75: 219-225. Battery cage systems for housing laying hens are being replaced by alternative systems including the deep litter system. At the same time, the substitution of meat and bone meal by vegetable matter in poultry feed mixtures is sought in the nutrition of laying hens. In the experiment, we compared the performance of laying hens of the ISA BROWN hybrid in both the cage system and the deep litter system, on a diet with the meat and bone meal content replaced by vegetable feeds (based on lupin). In the first group, 36 laying hens were kept in the deep litter system; in the second group, 36 laying hens were kept in cages. Over the period of nine months, the number of eggs laid, their weight, shell quality, the clinical state of the laying hens and incidence of their mortality were monitored daily. We found that in the cage system a higher number of eggs was obtained; a lower mean egg weight (p 0.05), and the number of laying hens which died was lower (p < 0.05) in comparison with the deep litter system. The results of the experiment demonstrate that, with the substitution of meat and bone meal by vegetable matter in the feed mixtures for laying hens, there are differences between the performance of laying hens from the deep litter system as compared to the laying hens from the cage system. The deep litter system better meets the requirements for the welfare of laying hens; however, it provides a lower yield. Rearing technology, vegetable feeds, number of eggs, egg weight, cracked eggs, mortality The traditional battery cage systems for the rearing of laying hens are being replaced by alternative systems to promote and increase laying hen welfare. Savory (2004) states that Council Directive 1999/74/EC laying down minimum standards for the protection of laying hens abolishes battery cage systems within the European Union from 2012. This Directive responds to public opinion requirements concerning the welfare of laying hens. However, scientific knowledge, in evaluating the battery cage system for laying hen rearing particularly in regard to production indicators, is not so unequivocal. This is due to the fact that the alternative systems often include higher risks to both the production and the health of laying hens. This is especially applicable to non-cage systems. The main issues requiring control in larger group floor housing are: parasitic disorders; the outbreak and spread of cannibalistic pecking; increased feed intake; misplaced eggs; the catching of spent hens; and air quality (Tauson 2005). Duncan (2001) cites the advantages of the battery cage system. He regards as positive the low incidence of disease, the low incidence of social friction, and the absence of problems resulting from litter. As disadvantages, he cites: the lack of physical space for laying hens; the lack of space for daily activities and nesting; the absence of opportunities for dust-bathing; the higher incidence of foot lesions. ACTA VET. BRNO 2006, 75: 219–225 Address for correspondence: Ing. Eva Voslafiova, Ph.D. University of Veterinary and Pharmaceutical Sciences Brno Department of Public Veterinary Medicine and Toxicology Palackeho 1 3, 612 42 Brno, Czech Republic Phone: 00420 541 562 773 E-mail: voslarovae@vfu.cz http://www.vfu.cz/acta-vet/actavet.htm Petermann (2003) found an increased incidence of mortality in alternative housing systems. De Boer and Cornel issen (2002) consider the battery cage system, particularly from the perspective of production and some health indicators, to be more beneficial than the aviary systems. Changes relating to the diet of laying hens are being promoted in the present practice of rearing laying hens. The animal protein in poultry feed, provided by meat and bone meal, is being replaced by vegetable protein from selected vegetable products. Such et al. (2002) and Mala et al. (2004) described the replacement of animal protein by vegetable protein based on lupin in broilers. Hadorn et al. (2000) focused on the replacement of animal protein in the diet of laying hens. The yield of laying hens, particularly in the number of eggs, can also be influenced by the incidence of mortality in laying hens. Petermann (2003) claims that the incidence of mortality in the deep litter systems, is high. Alternative systems, despite their benefit for welfare, thus encounter problems which remain unresolved. Taylor and Hurnik (1996) compared the long-term performance of laying hens in the battery cage systems and aviary systems. They did not detect any evidential differences in egg weight, in the total daily egg production per hen, in the production of egg mass per hen per month and in the number of cracked eggs. Vits et al. (2005) analysed the effect of furnished cages and two different small group systems on the production traits and egg quality traits of laying hens. The authors reported that the housing system and group size influenced egg production per hen, egg weight and the number of cracked eggs. Tauson et al. (1999) studied the number of cracked eggs in the battery cage system and the aviary system. They discovered that the number of cracked eggs was lower in the aviary system in comparison with the battery cage system. Abrahamsson and Tauson (1998) monitored the incidence of mortality in the rearing of laying hens. In the aviary system, they discovered a significant variation from 4.0 to 20.9% and explained this as the consequence of unpredictable cases of cannibalism. Sommer and Vasicek (2000) cite mortality in free-range poultry flocks at the level of 0 to 32%. Tauson et al. (1999) monitored the incidence of mortality in laying hens kept in cages and in laying hens kept in the aviary system. In laying hens in the aviary system, they detected mortality at the level of 21 to 27%, caused mainly in result of bacterial infections due to the pecking at naked skin by more aggressive laying hens. In the battery cage system, the mortality level did not exceed 7%. Similarly, Weitzenburger et al. (2005) reported that the incidence of mortality was greater in floor-reared laying hens than in the laying hens reared in conventional cages. The aim of our study was to compare the performance of laying hens of ISA BROWN hybrid in both the cage and deep litter systems, on a diet with the meat and bone meal content replaced by vegetable feeds (based on lupin). Materials and Methods A comparison was made between the egg yields of laying hens kept in two rearing technologies: the deep litter system and the cage system, on the same level of nutrition without animal protein. 72 ISA BROWN hybrid laying hens were divided into two groups at the age of 16 weeks. The first group of 36 laying hens was kept in the deep litter system; the second group was kept in conventional cages for laying hens. The microclimate and lighting conditions for rearing followed the technological standard for the rearing of this hybrid. Feed mixtures N1 and N2, in which animal protein was replaced by vegetable protein based on lupin, were supplied ad libitum using automatic feeders. The composition of the feed mixtures N1 and N2 is provided in Table 1. Water was supplied ad libitum using automatic drinkers. The experimental investigation, along with the collection of eggs, commenced at the 19th/20th week. The laying hens were observed for nine months (from 20 to 56 weeks of age). The number of eggs laid and their weight was monitored during this period on a daily basis. From the data collected, the mean egg weight, the mean number of eggs laid per hen per day, and the mean egg-mass production per hen per day were calculated monthly and then for the 220