The heritability of milk yield and fat percentage in the Friesian cattle in the province of Friesland

S.A.F. El-Shimy

Research output: Thesisinternal PhD, WU


The heritability of milk yield and fat percentage was calculated of herd-registered cattle in Friesland. The estimates were based on daughter-dam comparisons. Comparisons covered the first three lactations. The average heritability estimates of milk yield within sires, and according to the different kinds of soil, were 35.50 and 37.38 %, with daughter-dam regression and dam-daughter correlation, respectively. Under the same conditions the figures for fat percentage were 76.52 and 81.58 %, respectively.

When the effect of different soils was ignored, average heritability estimates for milk were 36.58 and 38.60 %, respectively. The corresponding figures for fat percentage were 76.40 and 81.60 %, respectively.

If the figures were not calculated on within-sire basis, the average heritability for milk yield was 39.60 and 40.60 %; whereas for fat percentage the estimates were 84.44 and 83.52 %, as calculated from daughter-dam regression, and damdaughter correlation, respectively.

The most reliable estimates of heritability were by the within-sire daughterdam regression calculated for each of the different soil types.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
  • de Jong, W., Promotor, External person
Award date23 Mar 1956
Place of Publication's-Gravenhage
Publication statusPublished - 1956
Externally publishedYes


  • genetics
  • heritability
  • genetic variation
  • cattle
  • raw milk
  • dairy breeds
  • productivity
  • profitability
  • animal husbandry
  • animal products
  • chemical composition
  • ingredients
  • netherlands
  • friesland

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