Correlation analysis of production and reproduction traits in twin living under identical and different conditions
2012
Bezdicek, J., Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Riha, J., Vyzkumny ustav pro chov skotu, Vikyrovice (Czech Republic)
The study was focused on the correlation of production and reproduction traits in holstein twins living under identical and different conditions. Only cows with complete pedigree were included into the research (HlOO). Evaluated traits in the field of reproduction were service period (period between first calving till getting pregnant), calving interval (period between first and second calving) and age at first calving. Production traits included milk yield at first lactation (kg of milk % of fat, % of protein, kg of fat and kg of protein). The number of studied twin living on identical farms was 830 pairs. The number of studied twin living on different farms was 104 pairs. In sibling pairs, living under different conditions, was found in all production and reproduction traits higher differences. These differences were not statistically significantly higher than in full sibling pairs living under identical conditions. It was found also higher variability in siblings living under different conditions. Higher correlations and coefficient of determination were found generally in full twin in all milk yield traits and also in age at first calving. On the other hand in case of other reproduction traits (service period and calving interval) the correlations were low. The results of a canonical correlational analysis show that 74.24 % is created by explicable variability in observed groups of twin. Out of than 69,83 % is a variability explicable by production traits. This conclusions confirm an important influence of environmental effects in production an reproduction traits.
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