Left displacement of the abomasum: relationship to age and medical history.

The present study shows that 5 years is the numerically most frequently observed age at onset of left displacement of the abomasum (LDA) in dairy cows, and that the risk of LDA actually increases with age (Fig. 1 and 2). A high prevalence (70-75%) of other or concurrent disorders among LDA cows is observed (Tables I and II). The apparent excess risk among LDA cows of getting other diseases throughout their lives, including retained placenta (RP), disappeared when adjustments were made for age (Tables III and IV) and it is concluded that LDA cows have a higher incidence of other disorders mainly because they tend to be older cows. A negative influence of RP and LDA on reproductive performance was finally observed (Table V).