Piena produktivitāte un kvalitāte atkarībā no govju vecuma. | Milk productivity and quality depending on cow age
2016
Cielava, L., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture | Jonkus, D., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture
The aim of our study was to determine to what extent cow age affects milk yield, composition and quality. For our study we used Latvian data Centre (LDC) data of 246 Holstein Black and White (HM) and 595 Latvian Brown (LB) breed cows which concluded at least 9 lactations and were culled until year 2014. We included data about cow milk productivity (milk yield, kg), composition (milk fat and protein content, %) and quality (somatic cell count, thousands mLE-1) in the data base. To analyse lactation as a significant factor, we used Bonferroni test. In our study we found that cow milk productivity has a tendency to increase until 7th lactation for HM breed cows, but analysed LB breed cows kept increasing their productivity until the 9th lactation. Milk protein and fat content was higher for LB breed cows, but they showed lower milk yield in all their productive life. Milk protein content was the lowest in the 1st lactation and it showed a significant increase until 4th lactation, however, milk protein content slowly decreased later. Milk fat content stays relatively stable until the 5th lactation, but there is a significant decrease until 9th lactation. Somatic cell count was significantly lower until the 4th lactation, and after there is a significant increase in each lactation. In 9th lactation somatic cell count exceeds quality milk requirements.
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