Union Catalogue of Agricultural Libraries in the Netherlands
The WUR Library Catalogue contains bibliographic data on books and periodicals held by the libraries of Wageningen University and Research Centre and some 15 associated libraries. Holding data are added to each record.
Subjects covered include Agrotechnology, Food and Food Production, Plant and Animal Sciences, Soil Science, Geo-information, Landscape and Spatial Planning, Water and Climate, Ecosystem Studies, Economics and Society.
The joint collections of the participating libraries cover a substantial part of the internationally available scientific literature in these disciplines.
As far as Dutch scientific literature in these fields is concerned, coverage can be considered near 100%, including much of the so-called "grey literature".
All titles are entered in their original language. Keywords are added to facilitate subject searching.
The database is updated every day and now contains over 830.000 records.
The effect of costs on the optimum breeding plan for selection for milk traits and the profitability of performance-test selection according to meat production were studied, including the consequences of beef crossing. Returns from breeding schemes were calculated from the expression of genetic superiority of selected parents (paths) in subsequent generations of offspring. Measuring the contribution of separate paths to returns was based on 'discounted expressions per cow'. The relative contribution of paths to returns and to annual genetic improvement differed, especially for path sire to breed daughter, showing a higher relative contribution to returns than to genetic improvement. A breeding plan with highest net returns (returns minus costs) was designated as optimum. Two types of breeding plans for selection for milk traits were compared: a system with semen storage during the waiting period and including slaughtering of bulls after production of a predetermined number of doses, and a system without semen storage. The first system proved to be economically advantageous. Optimum proportion selected, after performance testing, was between 1 in 2 and 1 in 4. Optimum weighing of milk and meat traits - the product of actual economic values and discounted expressions per cow - differed by path, and increasing proportion of beef crossing resulted in a shift of emphasis to milk traits. The conclusions remained unaltered if returns per cow from the expression of genetic superiority were calculated in subsequent years instead of generations, even though the generation approach gave systematic errors in discounted expressions.
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