EPIDEMIOLOGIC-STUDY OF SEVERAL CLINICAL-DISEASES, REPRODUCTIVE-PERFORMANCE AND CULLING IN PRIMIPAROUS SWEDISH CATTLE

An epidemiological study of stillbirth, dystocia, retained placenta, metritis, cystic ovaries and silent heat and their effect on the risk of culling and reproductive performance is presented. Data consisted of 69 832 Swedish Red and White (SRB) and 39 178 Swedish Friesian (SLB) first lactation records. Logistic regression and path analysis were used to estimate the effects of age, season and herd production level on the risk of diseases, interrelationships between diseases and the effect of diseases on the risk of culling. The least squares procedure was used to estimate the effects of diseases on reproductive performance. The general pattern of interrelationships between diseases was similar for the two breeds but a stronger link between dystocia, stillbirth, retained placenta and metritis was found for the SRB breed than for the SLB breed (odds ratios connecting diseases were about two times larger in SRB breed). The dominant disease with respect to culling was cystic ovaries which increased the risk of culling about three times. All other diseases (except ketosis) increased the risk of culling about 1.5 times. Most diseases had a negative effect on reproductive performance. The largest effects were associated with retained placenta, metritis, cystic ovaries and silent heat which increased days open by approximately 7, 20, 40 and 40 days respectively. © 1990.