4Heuer C, et al. Postpartum body condition score and results from the frist test day milk as predictors of disease, fertility, yield and culling incommercial dairy herds [J]. Dairy Sei, 1999,82(2) : 295 -304.
5Miller H V, et al. Endometritis of dairy cattle[J]. Diagnosis treatment and fertility Boy Pract, 1989, (15) : 1323.
