Twinning in dairy cows is looked upon as undesirable, due to management issues and resulting health problems. Continued increases in milk production over the last two decades in dairy herds has been associated with an increase in twinning rate (Wiltbank et al. 2000). The lactation number and level of milk production of the cow appear to be positively associated with increased ovulation rate and twinning (Wiltbank et al. 2000). Unfortunately, twinning is difficult to control by selection due to its association with milk yield and its low heritability (Komisarek and Dorynek, 2002). The aim of this study was to assess the effect of bearing twins on the health and performance of dairy cows.