Genetische Analyse des Legemusters in der Bodenhaltung im Hinblick auf neue Leistungsprüfungskriterien für die Legehennenzucht

Abstract. Title of the paper: Genetic analysis of the laying pattern in floor management
in terms of new performance parameters for breeding In order to facilitate a specific selection of laying hens which are suitable for alternative housing systems, it will be of advantage if the individual hens were tested in their later husbandry environment. Therefore, a new technology has been developed, the »Weihenstephan Funnel Nest Box«, which enables the automatic recording of these essential performance and nesting behaviour parameters of the individual hens in a group housing system. The exact oviposition times of 263 laying hens of Lohmann Silver line were recorded and used to analyse the laying pattern. Some results which were already pointed out in literature were thus confirmed, other brought new cognitions in terms of the oviposition pattern and about the pause following a laying sequence. A positive genetic correlation between the length of a laying sequence and the subsequent pause durations (r_g=+0.49) confirmed the tendency to longer breaks following an increasing laying sequence. The duration of a break was, however, not such an essential criteria for the productivity of a hen. More important in this context was the number of pauses which rises constantly with the number of laying sequences over the whole observation period. When the hens laid in shorter sequences, it was observed that the proportion of sequences grew, which was reflected as smaller number of registered eggs per hen (r_g =−0.73). The logical conclusion was the highly positive correlation between the length of a laying sequence and the number of registered eggs (r_g =+0.82). Closely associated with the length of a laying sequence, as well as the laying performance, was the parameter time interval between two laid eggs. The time interval between two laid eggs was significant shortened from the first to the third egg within one laying sequence and eventually reached for more than 24 h for most of the hens. The phenotypic and genetic correlation between the time interval and the laying performance was negative (r_p =−0.46 and r_g =−0.46). The heritability for the time interval was estimated at h²=0.17 which was similar to the heritability for number of eggs (h²=0.20). Slightly higher heritabilities were estimated for the indirect parameter of the time interval, the oviposition time of the third to the fifth egg in a laying sequence (h²=0.25, h²=0.34 and h²=0.29). Valuations in this range would be in regard of new performance testing parameter competitive to the parameter number of eggs and therefore, be tested in further investigations.