A universal index of uterine discharge symptoms from calving to 6 weeks postpartum

In this paper, a new uterine discharge index (D-index) was created and tested. It was based on a principal component analysis (PCA) of clinical findings of classical uterine discharge symptoms and rectal temperature during the postpartum period of dairy cattle. The PCA analysis revealed how uterine discharge features relate to each other and how they cluster together possibly representing different degrees of uterine inflammation. The D-index was the result of the multivariate PCA-analysis, and the D-index gives a continuous value between 0 and 10. It was demonstrated that the same scale, i.e. the D-index, can be used without any adjustment from 1 to 6 weeks post-calving. It is valid for any type of uterine discharge without defining the type of infection or differentiating between infection and contamination. The D-index was tested using the uterine involution data. Uterine involution was significantly delayed in the high-D-index group of cows. Similarly, in the test with all cows, involution was progressively delayed and the rate of involution of the pregnant horn was slowed down with the increase of the D-index values. It is concluded that the D-index can be a new practical, universal, tool for improved management of dairy cows in the postpartum period under commercial conditions.