caa a22 4500 388060298 CHVBK 20180307125118.0 cr unu---uuuuu 161130e199812 xx s 000 0 eng 10.1017/S1357729800033075 doi S1357729800033075 pii (NATIONALLICENCE)cambridge-10.1017/S1357729800033075 Effect of intermittent light regimens on the performance of intact male turkeys [Elektronische Daten] An 8-h photoperiod, compared with 12-, 16- or 23-h photoperiods, has been shown to reduce the incidence of injurious pecking and leg problems in intact male turkeys but to result in lower body weights, slower sexual development and less efficient food conversion. The effect of 8 h of illumination given as a solid photoperiod, as eight 1-h periods equally spread through the 24 h or concentrated into a 12-h part of the day on the performance of BUT 8 intact male turkeys was investigated. Fragmentation of the daily illumination increased body weight, improved food conversion efficiency but did not significantly affect food intake. Increased sexual displaying and significantly better food conversion between 16 and 20 weeks by the two intermittently illuminated groups strongly suggested that both regimens were interpreted as stimulatory daylengths. Generally, losses due to mortality and culling were higher in both fragmented groups, while injurious pecking was higher in 8(1L: ID) birds before 5 weeks and in birds given a 12-h ‘subjective day' after 5 weeks than in 8-h controls. Culling due to leg problems was significantly higher in birds on the 8(1L:2D) regimen but the incidence of leg imperfections was minimal (< 0·037) in all groups. Both intermittent groups but the 8(1L: 2D) in particular, showed a reduced response to hand movement across the eyes compared with 8-h controls. The controls ate proportionately more food during their 16-h dark period than did the intermittent group during their 12-h ‘subjective night', though both groups increased their ‘nocturnal' feeding with age. Copyright © British Society of Animal Science 1998 behaviour nationallicence light regime nationallicence performance nationallicence photoperiod nationallicence turkeys nationallicence Lewis P. D. Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS18 7DU Perry G. C. Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS18 7DU Sherwin C. M. Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS18 7DU Animal Science Cambridge University Press 67/3(1998-12), 627-636 1357-7298 67:3<627 1998 67 ASC https://doi.org/10.1017/S1357729800033075 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1357729800033075 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lewis P. D. Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS18 7DU NATIONALLICENCE 700 1- Perry G. C. Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS18 7DU NATIONALLICENCE 700 1- Sherwin C. M. Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS18 7DU NATIONALLICENCE 773 0- Animal Science Cambridge University Press 67/3(1998-12), 627-636 1357-7298 67:3<627 1998 67 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge