Tibiale dyschondroplasie

In maart 2000 is een EU-onderzoek gestart om meer kennis te verkrijgen over bewegingsstoornissen bij vleeskalkoenen. Praktijkonderzoek Veehouderij zal zich in het onderzoek richten op tibiale dyschondroplasie (TD). Verschillende factoren worden onderzocht, zoals de effecten van omgevingstemperatuur, kalkoenmerk, sekse, lichtschema, voerbeperking en 1,25- dihydroxycholecalciferol (vitamine D). In dit artikel worden de resultaten weergegeven van de eerste proef. Van omgevingstemperatuur en kalkoenmerk wordt verondersteld dat deze de groei van de dieren beonvloeden en daarmee een effect kunnen hebben op het ontstaan van TD

Insects for turkeys

In a trial with 14 pens with in each 20 turkey pullets (males, not treated) research has been conducted to the effect of feeding 12% insect larvae (Black Soldier Fly) on technical results and behaviour. The birds were kept until 5 weeks of age. The larvae fed groups ate less, had a higher growth rate, a better feed conversion ratio and a higher body weight at 5 weeks of age. Mortality was not different between the treatments. Compared to the controls the BSF larvae fed birds had less feather damage and less skin damage and performed less aggressive behaviour. Also they performed less foraging behaviour in the third and fifth week compared to the controls and a lower water intake. On the other hand at five weeks of age the BSF larvae fed birds had more footpad lesions than the controls, although litter quality did not differ between the treatments. In conclusion it can be stated that feeding insect larvae does give small advantages, but does not solve the problem of injurious pecking

Final report TransForum WP-046 : images of sustainable development of Dutch agriculture and green space

In the project “Images of sustainable development of Dutch agriculture and green space” three PhD candidates studied the topic of images in sustainable development. Frans Hermans focused on the topic of societal images and their role and influence in innovation projects. The title of his subproject was “Social learning for sustainability in dynamic agricultural innovation networks.” Joost Vervoort explored the topic of “visualisation”, that is, using and producing images for specific purposes, in the context of innovation projects and programmes, in a subproject called “Step into the system: interactive media strategies for the exchange of insights on social-ecological change.” Finally, Dirk van Apeldoorn took a complex adaptive systems approach to images. He modelled various agro-ecosystems to compare images of those systems with the behaviour of those systems. His subproject was called “Modeling resilience of agro-ecosystems.

Invloed van lichtschema, mate van bijstrooien en bezetting op de uitwendige kwaliteit van kalkoenen

In Maarheeze is in het kader van het kwaliteitsonderzoek een proef uitgevoerd waarin is gekeken naar het effect van lichtschema, bezetting en de mate van bijstrooien op de uitwendige kwaliteit

Omgevingsverrijking voor vleeskalkoenen = Environmental enrichment for turkeys

A desk study has been conducted to study the possible environmental enrichments in order to reduce injurious pecking behaviour in intact turkeys. Free hanging materials are attractive to turkeys and are technically and economically feasible. Perches and elevated platforms are less feasible

Vleeskalkoenen doen het goed op gedeeltelijk verhoogde strooiselvloer

De gedeeltelijk verhoogde strooiselvloer leidde in deze proef opnieuw tot goede technische resultaten en een behoorlijke ammoniakreductie. Het wel of niet frezen van het strooisel had geen invloed op de technische resultaten maar wel op de ammoniakreductie

Voerbeperking op jonge leeftijd bij slachtkuikens

In 1990 werd onderzoek verricht naar voerbeperking op jonge leeftijd bij slachtkuikens op het pluimveeteeltproefbedrijf Maarheeze. In de laatste opzet werd voerbeperking door middel van lichtbeperking beproefd

Rational Attention Allocation over the Business Cycle

The literature assessing whether mutual fund managers have skill typically regards skill as an immutable attribute of the manager or the fund. Yet, many measures of skill, such as returns, alphas, and measures of stock-picking and market-timing, appear to vary over the business cycle. Because time-varying ability seems far-fetched, these results call into question the existence of skill itself. This paper offers a rational explanation, arguing that skill is a general cognitive ability that can be applied to different tasks, such as picking stocks or market timing. Using tools from the rational inattention literature, we show that the relative value of these tasks varies cyclically. The model generates indirect predictions for the dispersion and returns of fund portfolios that distinguish this explanation from others and which are supported by the data. In turn, these findings offer useful evidence to support the notion of rational attention allocation