engleski

The effect of recording season on the estimated prevalence risk of mastitis in first parity Simmental cows

The aim of this study was to determine the variability of daily lactose content and somatic cell count (SCC), as an indicator of mastitis risk, depending on the season and based on milk recording data. The statistical analysis used data on test-day records of the first parity Simmental cows, collected during the five-year period, during regular milk recording. All independent variables (days in milk - DIM ; daily milk yield - DMY ; age at the first calving - AC and milk recording season - MRS) included in the statistical model statistically highly significant effect (p <0.001) affected the analysed traits (daily lactose content and logarithmic SCC (logSCC)). The highest daily lactose content was recorded during the spring season (4.590%), and the lowest (4.513%) in the autumn months. In contrast, the log values of somatic cell count were the lowest in spring (16, 017), and highest in autumn (16, 180). The research results indicate that the variability of daily lactose content and SCC, as well as prevalence risk of mastitis in Simmental first parity cows depends of daily milk production, stage of lactation, age at first calving, and season of milk recording. Therefore, those effects should be taken into account in the statistical model for the estimation of the mastitis prevalence risk in dairy cows based on milk recording data.

mastitis ; lactose ; milk recording ; seasons ; indirect estimation

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