Relationships between the incidence of health disorders and the reproduction traits of Holstein cows in the Czech Republic

The objective of this study was to evaluate the relationships between several health disorders: milk fever (MF; hypocalcaemia and parturient paresis), retained placenta (RP; retained foetal membranes), metritis (ME; endometritis and pyometra), ovarian cysts (OC; follicular and luteal cysts), clinical mastitis (CM), and lameness (LS; foot and leg problems) as affecting the reproductive performance of dairy cows. The dataset of 1 432 Holstein cows calving between January 2000 and April 2004 from 4 commercial dairy herds was analyzed by the linear regression model which included the effects of herd-year-season of calving, parity, FCM yield level, incidences of studied fertility and health disorders, and regression on the first calving age within parity. It was proved that fertility disorders relating to parturition, such as RP and ME, had a significant influence (P < 0.01 to P < 0.0001) on the evaluated reproduction parameters, i.e. days from calving to the first AI service (DAI), open days (OD), and the number of inseminations needed for conception (NAI). A significant effect (P < 0.0001) of OC on all reproduction parameters was also found. Mastitis and lameness occurring during lactation had significant effects on OD and NAI (P < 0.05 to P < 0.0001). The milk fever occurrence was related significantly only to a longer period to the 1st AI (P < 0.01). In general, cows with health disorders are inseminated later and they conceived later after their previous calving compared to healthy cows, and need more inseminations for conception.