Some reproductive indexes of thirty dairy herds in the Po valley

Abstract

The need of increasing the daily milk yield often has negative backup on herd fertility (Westwood et al., 2002). Culling because of reproductive failure is a cost in dairy breeding. The reproductive efficiency is often expressed as days open (DOPN) or calving interval. However, these indexes are a function of the pregnancy rate (PR) which is calculated as the heat detection rate (HDR) times the conception rate (CR) (Ferguson, 1991). Thus, the herd reproductive performance is affected by HDR and CR (Maatje et al., 1997; Nir, 1996, Ferguson, 1996). This work was conducted to estimate reproductive efficiency of cows from thirty herds of the Po valley.........

Keywords

• cow, fertility indexes, odds ratio