TY  - JOUR
T1  - Genetic and Phenotypic Trends of Selected Production Traits in Black and White Dairy Cattle Populations of Poland
AU - Varisella, E. AU - Dymarski, I. AU - Sobek, Z. AU - Nienartowicz-Zdrojewska, A. AU - Rozanska-Zawieja, J. 
JO  - Journal of Animal and Veterinary Advances
VL  - 12
IS  - 23
SP  - 1681
EP  - 1689
PY  - 2013
DA  - 2001/08/19
SN  - 1680-5593
DO  - javaa.2013.1681.1689
UR  - https://makhillpublications.co/view-article.php?doi=javaa.2013.1681.1689
KW  - production traits
KW  -genetic trend
KW  -
KW  -Dairy cattle
KW  -milk
KW  -protein
AB  - Monitoring genetic trends for production and functional traits is an important element of breeding work. In the present study, researchers analyse genetic and phenotypic trends for some production traits in Polish Black and White dairy cattle population. In the analysis the information on 6454 cows born to 709 sires was used and the time span studied was 1905-2006. For all of the analysed traits, i.e., milk, butterfat and protein yields (kg) and percentage composition of milk (%) in subsequent lactations, the observed genetic trends were positive during the entire analysed period (over 100 years). The linear increase of genetic trend was not equal for each of the traits as selection intensity had been changing and more acurate evaluation methods were introduced to identify superior animals as parents for the next generation.
ER  -