Wat is duurzaam fokken? Grenzen aan selectie

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1 Wat is duurzaam fokken? Grenzen aan selectie Prof. em. E. Decuypere 6 november 2013 Motivation in the past: increased animal production and productivity New signal: cheap and safe food but not at any cost concern/threatening by the public: nature of food; food safety? are the new (bio)technologies applicable to man? animal welfare? predominance of economics? 1

2 After World War II production efficiency of production stock or herd size, farm dimension specialisation, mechanisation 2

3 Reaction on industrialisation, specialisation and mechanisation From animal-machine Animals as living and sensible beings Utilitarian approach of animal welfare Pathocentrism: animal liberation (1975, P. Singer) Zoocentrism (T. Regan) condemnation / rejection of animal husbandry or any instrumental use of animals in its most extreme form Sustainable animal production = livestock farming with care Principles: Health and safety of animals and man: one health Customised care: ensuring robustness, dignity and integrity No nuisance from environmental and societal perspective Credible performance (from socio-economic perspective) Implementation of concrete measures is a challenge; should be in relation to the different types of animal husbandry practiced in developed and developing countries (from Scholten et al.; NJAS 2013) 3

4 What is careful livestock farming? Ethical concept Layered meaning theory of moral circles Chance or opportunity to reach caring, sustainable farming (Nijland et al. NJAS, 2013) Layers of increasing inclusivity of care on basis of social and temporal dimensions. 4

5 Selection limits for growth and feed efficiency? Reached because of: Exhaustion of genetic variability quantitative nor molecular genetics give indication Unwanted correlated responses associated with continued selection for production efficiency EXAMPLE: unidirectional selection in broiler production Unwanted responses from selection EXAMPLE: Broilers Feed consumption: 95% slaughter population 5% breeder population In prolific species poultry, the majo consumed by the generation (95% breeder populatio Therefore, unwa responses are m occur in poultry a in broiler product the unidirectiona Strong unidirectional selection: More unwanted responses in broiler production 5

6 Energy intake per unit meat output (MJ/kg) 11 Extreme growth Reproductive efficiency Incompatibility growth/reproduction more pronounced in Species with high prolificacy Multiparous mammalian farm animals Therefore: Focus selection goals: Slaughter generation Growth Feed conversion Carcass quality Breeder generation Reproduction parameters 6

7 Further improvements cause dilemmas 3 dilemmas for broiler meat production (apparent since 1980) 1 fast growth and feed conversion VS. changes in lean/fat tissue ratio 2 ponderal and energetic efficiency of growth and feed conversion ration (FCR) VS. metabolic disorders 3 fast growth and extreme lean tissue growth VS. reproductive effectiveness of the breeder Dilemma 2: weight vs leg problems in broilers apparently simple and direct link between selection for increased weight at young age leg problems (tibia dyschondroplasia, twisted legs, ) BUT not so directly mechanistically evident: next slide 14 7

8 Dilemma 2: weight vs leg problems in broilers Tibia Dyschondroplasia (TD) and body weight in ad lib fed broilers selected for 4 generations for feed conversion efficiency: for growth upon ad lib feeding: for growth upon restricted feeding: FC-line GL-line GR-line TD score sex Frequency of Dyschondropplasia (TD, %) Body Weight (g) FC GL GR FC GL GR No TD Light TD M Severe TD No TD Light TD F Severe TD D1/2: Link weight leg problems? Selected Sexe Twisted legs (%) Appearance of Dyschondroplasia (%) Body weight against twisted legs against twisted legs + for body weight M for body weight against twisted legs against twisted legs + for body weight F for body weight

9 D3:Fast and lean growth vs reproduction Domestic poultry: negative relationship between body weight and reproductive efficiency Selection for growth rate in broiler chickens reduction of the reproductive capacity of parent stocks Parent of meat-type poultry genetic potential of fast, efficient growth + reproduction Maximize egg and chick production quantitative feed restriction optimum degree and timing still to be elucidated 17 A double broiler breeder paradox Reproductive efficiency BBP Health and metabolic disturbances welfare Productivity, resource efficiency Animal welfare, and integrity 9

10 Robustness Selective breeding in terms of production + traits related to health and welfare improve robustness Robustness = production potential resilience to external stresses physiological ability to maintain or re-establish homeostatic state or balance Robustness Should be integrated in the breeding goal Should not be achieved by violation of the integrity ~ telos of an animal Notion of integrity is a requirement of robustness (Star et al., 2008) 10

11 Uit De gouden kooi: over het ontstaan van het huisdier van A. GAUTIER 11

12 Veranderende houding in de mens-dier relatie Verlichting en rationalisme Wetenschap & Technologie Industriële revolutie en stagnatie van de landbouw Vanaf 1880: impact Amerikaans graan crisis in de landbouw, de veeteelt terug belangrijk Voor en vooral nà WO-II: mechanisatie schaalvergroting specialisatie intensificatie en instrumentalisatie van dieren Veranderende houding in de mens-dier relatie Dubbeldoeldieren verdwijnen (specialisatie) Minder grondgebonden veehouderij Kennis- en kapitaalsintensief Aan het oog onttrokken, Band met individuele dieren verdwijnt Kloof tussen producent en consument van dierproducten 12

13 Verscheiden mens-dier relaties Onderscheiding obv bv diergeneeskundige kosten die men bereid is te dragen voor een dier Indeling en definitie van : nutsdieren (landbouwhuisdier, proefdier, werkdieren) gezelschapsdieren hulpdieren hobbydieren schadelijke dieren exotische dieren wilde en jachtdieren Muskus rat Paard Schaap Konijn Merkwaardige gelijkenis met de bestiaria van de Middeleeuwen! Conclusie Er is een ambigue houding t.o.v. de verschillende gedomesticeerde dieren, ook m.b.t. eugenetica. all animals are equal but some are more equal than others (G. Orwell, Animal Farm) Ofwel instrumenteel gebruik van dieren binnen de grenzen van hun welzijn en/of integriteit m.a.w. speciesisme is niet moreel verwerpelijk Ofwel kunnen zij NIET ten bate van de mens worden gebruikt, en dit voor alle huisdieren inclusief proefdieren, gezelschapsdieren, (en niet opportunistisch enkel voor nutsdieren) m.a.w. is speciesisme verwerpelijk 13

14 Bedankt voor uw aandacht! 14