| Abstrakt: |
Background: The productivity and profitability of dairy cattle depend largely on reproductive performance. Thus, this study was intended to evaluate the reproductive performance of Jersey cattle raised under semi-intensive management system. Methods: A retrospective analysis consisted of data collected for the last 33 years was conducted. The fixed effects fitted were birth period, calving period, service period, birth season, calving season, service season, parity and genetic group. The general linear model procedure of SAS was used for the statistical analysis of data. Result: The overall least-square means for age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and the number of services per conception (NSPC) were 22.93±0.22 months, 32.95±0.22 months, 494.16±3.68 days, 221.09±3.73 days and 1.99±0.03, respectively. Year, season and parity had a significant effect on most of the investigated reproductive traits. Imported Jersey cows had an extended CI and DO than farm-bred cows. Besides, the inconsistency of management and variability of climatic variables across year and season seems to have a considerable influence on the reproductive efficiency of cows. Therefore, the improvement in the level of management and selection of parents based on their breeding value would be improve the reproductive performance of Jersey cows. [ABSTRACT FROM AUTHOR] |
