|
|
|
|
|
| Su, Guosheng; Kjaer, Jørgen B.; Sørensen, Poul. |
| Variance components and selection response for feather pecking behaviour were studied by analysing the data from a divergent selection experiment. An investigation show that a Box-Cox transformation with power =-0.2 made the data be approximately normally distributed and fit best by the given model. Variance components and selection response were estimated using Bayesian analysis with Gibbs sampling technique. The total variation was rather large for the two traits in both low feather pecking line (LP) and high feather pecking line (HP). The standard deviation was about three times as large as the mean in the observed scale, and about the same value as the mean in the transformed scale. Based on the mean of marginal posterior distribution, in the Box-Cox... |
| Tipo: Journal paper |
Palavras-chave: Breeding and genetics. |
| Ano: 2005 |
URL: http://orgprints.org/6570/1/6570.pdf |
| |
|
|
| Sørensen, Poul; Danell, Brigitte; Brenøe, Ulrik; Tuiskula-Haavisto, Maria. |
| The poultry breeding is world wide concentrated in few and large breeding companies and none of them are situated in Nordic countries. Regarding egg laying stock the hybrids offered by these companies are primarily developed in order to produce in cage systems and although they are high producing stock they has some short comings when kept in free range systems in terms of inadequate behaviour, mislaying of eggs and sometimes high mortality. The question of using cages for keeping hens has been a matter of much concern for many people and an animal welfare approaches has lead to regulations in individual countries as well as at the EEC level. In Sweden use of conventional cages was forbidden from 2002 and the EEC has given rules which declare that it... |
| Tipo: Report |
Palavras-chave: Breeding and genetics. |
| Ano: 2004 |
URL: http://orgprints.org/7196/1/7196.rtf |
| |
|
|
| Sørensen, Poul. |
| Regarding access to breeding material for laying hens to organic egg production the following can be concluded: The breeding material available is genetically adapted to the cage systems. This cage adapted material has a shortcoming regarding behaviour in larger flocks that manifest in: too high tendency to feather pecking and cannibalism, and, independent of flock size, also to many mislaid eggs. Experiments has shown that feather pecking, cannibalism and nesting behaviour can be improved by selection. A search for alternative breeds/hybrids has not yet given the ideal "Organic hen". There seem to be a possibility for adaptation of laying bird to diets with lower crude protein that makes a production possible based on "home grown" crops even in Northern... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Poultry; Breeding and genetics. |
| Ano: 2001 |
URL: http://orgprints.org/9/1/GENETIC_ADAPTATION_TO__ORGANIC.doc |
| |
|
|
| Sørensen, Poul. |
| Økologisk ægproduktion begyndte for ca. 6 år siden, og har siden da været gennem ganske mange problemer. Dødeligheden over de sidste 6 år har været 3-7% højere i den økologiske produktion end hos konventionelt fritgående høner. Selv om de to produktionssystemer ligner hinanden, er der forskelle, der kan være med til at forklare den højere dødelighed: 1. Det er ikke tilladt at næbtrimme økologiske høner 2. I den økologiske produktion er der store restriktioner på forebyggende sygdomsbehandling og 3 gange længere tilbageholdelses tid efter sygdom 3. Det er vanskeligere at sammensætte en balanceret fodring i den økologiske produktion. Det er almindelig accepteret, at de høneafstamninger, der idag er på markedet beregnet til høj ægproduktion i... |
| Tipo: Newspaper or magazine article |
Palavras-chave: Animal husbandry; Breeding and genetics. |
| Ano: 2001 |
URL: http://orgprints.org/7191/1/7191.rtf |
| |
|
|
| Su, Guosheng; Kjaer, Jørgen B.; Sørensen, Poul. |
| The correlated changes in egg production, egg quality, and feed efficiency due to selection for or against feather pecking (FP) were investigated by analyzing the data from an experiment including two divergent selection lines and a control line. The experiment was conducted with hens at the age of 42 to 46 weeks (hatch 1) and 39 to 43 weeks (hatch 2) in the fifth generation of selection. Number of FP bouts per hour in low FP line (LP) was significantly lower than that in high FP line (HP) (0.38 vs. 2.01), and total plumage score in line LP was significantly better than that in line HP (16.9 vs. 11.6). During the four weeks, egg number and egg mass in line LP were significantly higher than those in line HP (24.4 vs. 18.3, and 1223 g vs. 1132 g). On the... |
| Tipo: Journal paper |
Palavras-chave: Health and welfare; Breeding and genetics. |
| Ano: 2006 |
URL: http://orgprints.org/7195/1/7195.pdf |
| |
|
| |
|
|
| Kjaer, Jørgen B.; Sørensen, Poul; Su, Guosheng. |
| A selection experiment was initiated in 1996 in which selection for (HP line) and against (LP line) feather pecking was performed. The foundation stock was a White Leghorn layer strain established in 1970 and maintained since then as a random bred control line at the Institute. Six hatches were produced over three generations. At the age of 68 wk (gen. 0, 1996), 35 wk (gen. 1, 1997), 30 wk (gen. 2, 1998), and 27 wk (gen. 3, 1999) female birds were transferred to observation pens and their feather pecking behaviour was recorded. In each generation, 30 females and 8 males were selected from approx. 200 females and 60 males. Selection criteria was breeding value estimated by animal model on the trait ‘number of bouts of feather pecking per bird per hour’.... |
| Tipo: Journal paper |
Palavras-chave: Breeding and genetics. |
| Ano: 2001 |
URL: http://orgprints.org/1565/1/Final_edition.pdf |
| |
|
| |
|
|
|
