The relationship between fertility and intermediate optimum type traits in Polish Holstein-Friesian cows

The purpose of this study was to find early indicators of cow fertility. Genetic correlations of two types of conformation evaluations, routine and modified, with reproduction traits were estimated. Data consisted of type evaluations and fertility measures of primiparous Holstein-Friesian cows born from 2005 to 2006. The number of records ranged between 4731 and 8041 depending on the trait. Type traits with intermediate optima were evaluated using routine and modified scales. In the modified system, the more desirable form of a trait received the higher score. A multi-trait animal model and Gibbs sampling were applied. Among modified type traits the highest genetic correlations were found between non-return rates for cows and rear legs side view (-0.36), between days open and rump angle (0.36), and between interval from calving to first insemination and rump angle (0.35). Genetic correlations of routine type traits with fertility measures were low for udder traits and rump angle (-0.08 to 0.10) and moderate for leg traits (-0.34 to 0.44) and body depth (-0.41 to 0.36). Modified scores for rear legs side view and rump angle, and routine scores for body depth and foot angle may be used as early indicators of cow fertility in Polish Holstein-Friesians.