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Library Catalogue

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    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.

Record number 104571
Title De invloed van erfelijkheid en milieu op de samenstelling van de melk bij Friese koeien en de praktische mogelijkheid van selectie op het eiwitgehalte
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door Rommert Douwe Politiek
Author(s) Politiek, R.D.
Publisher Drachten : Folkertsma
Publication year 1957
Description 174 p ill
Notes Proefschrift Wageningen
Tutors Jong, Prof. Ir. W. de
Graduation date 1957-03-15
Dissertation no. 218
Author abstract show abstract
The milk composition of individual cows was studied especially as to protein content. In total 729 cows were tested including 238 dam-daughter pairs, 6 large progeny groups of bulls used in artificial insemination and 20 small progeny groups of bulls in natural service. Milk production, and fat, protein, casein, lactose and solids-not-fat were estimated during lactation.

Environmental influences on milk production and composition were studied, e.g. lactation curve, month of calving, age of cow, duration of lactation. The average percentages fat and protein of individual cows were only slightly influenced and generally in the same direction by environmental factors.

The variation in protein percentage (σ= 0.17) was smaller than that of fat = 0.27) but this variation was still enough to permit successful selection on percentage protein.

The protein percentage was positive correlated with fat content (r = +0.54). The percentage fat and protein were both largely determined by genetic factors (h 2= about 0.7). Taking account of the purpose for which milk was used, e.g. cheese production, especially protein was an economically important component of milk.

Protein analysis on a large scale was cheap. For the Netherlands, and for Friesland in particular, it was definitely warranted to base payment for milk on percentages fat and protein and to select both on fat and protein.

Online full textINTERNET
On paper FORUM ; STACKS ; NN08202,218
Keyword(s) (cab) animal products / chemical composition / ingredients / raw milk / cattle / genetics / heritability / genetic variation / animal breeding
Categories Cattle
Publication type PhD thesis
Language Dutch; Flemish
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