PhD thesis
Untersuchung der Eignung alternativer Putenherkünfte für ein ökologisches Haltungssystem



Publication Details
Authors:
Olschewsky, A.
Publication year:
2019

Abstract

The proportion of organic turkeys in Germany is with less than 2 % of the total number of turkeys comparatively low. However, the sector is attracting particular attention due to the use of fast growing conventional birds and sometimes high prevalences of various performance- and husbandry-related diseases. Little information is available on the extent of these problems when using alternative, slower-growing turkeys. 

The present study therefore examined the results of slower growing turkey genetics under commercial organic conditions in terms of behaviour, health, meat quality and performance. Hockenhull Black (robust with reduced performance potential) and Hockenhull Large Bronze (suitable for free-range husbandry with a similar performance as Kelly BBB) were compared with the reference line Kelly BBB, which is already used more frequently as a slower growing turkey. Rearing and fattening of about 2 x 50 male turkeys per hybrid line in three batches (a total of 844 animals) were scientifically monitored on a biodynamic farm in a mobile stable from 2015 to 2018 by the following investigations: Continuous documentation of mortality and causes of losses; recording of the use of certain functional housing areas by direct and video observation with Instantaneous Scan Sampling, scoring of plumage and skin condition as an indicator for feather pecking, cannibalism and social interactions, and assessment of walking ability, leg position and footpad condition in the 7th, 16th and 25th week of life. After parts of each group were slaughtered in the 17th, 20th and 25th week of life, footpad dermatitis, breast blister and breast buttons as well as injuries or scratches were assessed on the carcasses. In addition, live and carcass weights, weights of valuable cuts, pH values, drip losses and blood points were recorded at these times. Daily weight gain and feed conversion were also calculated. The data were analyzed for effects of "genetics" and "week of life" and their interaction with linear or generalized linear mixed models and effect sizes were calculated. Some of the data were evaluated with nonparametric methods due to a small sample size or lacking normal distribution. 

Only few significant differences with mainly small effect sizes between the different genetics were found. Exceptions were a significantly poorer leg health of Hockenhull Bronze, increased occurrence of breast blisters in Kelly BBB turkeys and a high amount of footpad dermatitis in Hockenhull Black birds. However, the latter were characterized by low mortality, fewer malpositions of the legs and a reduced injury rate. Overall, the prevalence of animal welfare problems was predominantly lower than in comparative studies. It can therefore be concluded that both alternative genetics as well as the reference genetic can be reared and fattened under organic conditions with 100 % organic feeding and good management in such a way that an acceptable to good status in terms of behaviour, health and meat quality is achievable at comparatively high performances.


Last updated on 2019-30-09 at 09:33