Analysis in a time series of milk-yield production

Abstract

Monitoring of milk yield is used as a tool for the operative management of individual cows as well as management at the herd level. Nevertheless, sometimes a general knowledge of the significance of a particular problem is not sufficient for appropriate managerial decisions and a need arises to weigh up the impact of particular disorder on a particular herd. Than it is necessary to evaluate animal data from a longer period, different lactation order etc. The aim of the introduced research is to present methods for comparing the milk yield of cows in different epochs. The data from selected Holstein dairy herds in the Czech Republic from an 8-year period was used as a model. Several statistical hypotheses (zero trend, absence of seasonal variation) were being tested. The results indicated a requirement to consider the relationship between labour date and milk production. Our statistical analysis enabled us to draw up a table of milk-yield indices showing the average changes in 305-day yield values among lactations and years.