Gene Technology and Milk Production

Maruša Debeljak¹, Simona Sušnik¹, Tamara Miloševič-Berlič¹, Juan F. Medrano² and Peter Dovč¹*

¹Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, SI-1230 Domžale, Slovenia
²Department of Animal Science, University of California, Davis, CA 95616-8521, USA 

Article history:
Received January 19, 2000
Accepted May 2, 2000

Key words:
DNA technology, milk composition, regulation of gene expression, growth hormone, QTL (quantitative trait loci)

Summary:
The introduction of gene technology to the practice of animal breeding has opened new venues as we enter the 21st century. Using DNA based genotyping the new genetic variants of milk protein genes were identified and basic regulatory mechanisms of the lactoprotein gene expression were discovered. Genomic and cDNA sequences for all major lactoprotein genes were deposited in the GenBank and comprehensive analysis of these data revealed the molecular basis of some quantitative effects which have been reported to be associated with particular genetic variants. In addition, comprehensive analysis of the animal genome enabled chromosomal localization of candidate regions bearing quantitative trait loci with effects on milk traits. The possibility to assess maternal and paternal inheritance of desired lactoprotein alleles can be utilised for efficient selection of desired haplotypes. Beside the possibility to change the milk composition through selection of favourable lactoprotein alleles, there is also the chance to manipulate milk composition via metabolic pathways, which regulate fat and carbohydrate synthesis. Reduction of the amount of saturated fatty acids and lactose in bovine milk are two interesting tasks for the future in order to adapt bovine milk to the requirements of modern human nutrition and to make bovine milk acceptable for special groups of consumers. Finally, the availability of recombinant growth hormone induced new technologies of milk production based on prolonged lactation with high persistence of milk yield. 

*Corresponding author:          This email address is being protected from spambots. You need JavaScript enabled to view it.
                                              ++386 (0)1 7241 005