Clinical disorders in Holstein cows: Incidence and associations among lactational risk factors

A retrospective study of possible associations among lactational incidence risks of clinical health disorders in the current lactation in dairy cows f rom selected Holstein herds in Lower Saxony (Germany) was carried out on th e basis of data obtained from herd health and production management pro gra mme. The associations were studied using the chi (2) test. Data on 2197 lac tations of 1074 cows originated from 10 commercial herds participating for 2 to 5 years (from 1990 to 1996) in the programme. The herds had 48 dairy c ows on average, milk yield of 8137 kg and mean parity of 2.9. We tested eig ht clinically identifiable health disorder complexes reaching the following lactational incidence risks: parturient paresis (7.0%), retained placenta (8.9%), displaced abomasum. (1.1 %), metritis (23.6%), clinical ketosis (1. 7%), clinical mastitis (21.6%), ovarian cysts (11.7%) and claw diseases (19 .5%). Dairy cows suffering from parturient paresis were at 1.4 (1.1 - 1.7) and 1.7 (1.3 - 2.2) significantly (P less than or equal to 0.05) greater ri sk of suffering from metritis and clinical mastitis, respectively, in the c urrent lactation. Retained placenta was significantly (P less than or equal to 0.05) associated with 3.0 (2.6 - 3.5) times higher lactational incidenc e risk of metritis, which was a significant (P less than or equal to 0.05) risk factor for ovarian cysts (odds ratio 1.4; 95% confidence interval 1.1 - 1.8). These associations provide further support to the notion that healt h problems in dairy cows tend to occur as a complex, especially in the post partum period.